domain: info shs

text:
Vincent Jaillot
email: vincent.jaillot@liris.cnrs.fr

Manon Istasse

Sylvie Servigne

Gilles Gesquière

Michel Rautenberg

Isabelle Lefort

Describing, Comparing and Analysing Digital Urban Heritage Tools: A Methodology Designed with a Multidisciplinary Approach

Keywords: Digital Heritage, Urban Cultural Heritage, Multidisciplinary, Analysis, Methodology, Citizen Participation

Urban cultural heritage is taking full advantage of digital technologies. This can be seen in the great number of digital tools for representing and interacting with cultural heritage (digital urban heritage tools) that are intended for the public or designed in the context of research programs and dedicated to a more limited public. These tools do not only display heritage, but also permit interaction with it, even allowing users to contribute with their own data (knowledge, memories, documents, questions, etc.). In this article, we present and apply a methodology for describing, analysing and comparing these tools. After observing the lack of such a methodology, we built DHAL (Digital urban Heritage tools AnaLysis). This methodology allows for qualitative and multidisciplinary analysis of digital urban heritage tools that combine at least two of the following aspects: digital representation of the city, multimedia data documenting the city and its heritage, and participatory functionalities for adding to the digital city. Firstly, we introduce the methodology and the process established for building it. We then show its application, usefulness and full potential in the context our project (Fab-Pat) by testing it on twelve tools. This implementation -one possible among others -allows the positioning of the Fab-Pat tool among similar tools and a detailed description of them. We conclude with a discussion of the methodology's advantages and potential avenues for future developments.

INTRODUCTION AND RESEARCH AIMS

Can urban cultural heritage become accessible to a wide audience through digital technologies? Today, this is the goal of many digital tools 1 for representing and interacting with cultural heritage. We call them digital urban heritage tools. They share existing knowledge in the form of apps or websites that are accessible to everyone or specific to an audience of specialists. In this way, they allow for understanding and perceiving the city, and, with a diachronic approach, its evolution over time. In some cases, participatory functionalities invite professionals and non-professionals to display what urban cultural heritage is for them, participating in creating new knowledge. These tools take various forms. Some are databases (e.g. Australian Heritage Database 2 ), while others offer types of interaction with data such as virtual tours (e.g. Avignon 3D - [START_REF] Berthelot | The Avignon bridge: a 3D reconstruction project integrating archaeological, historical and geomorphological issues[END_REF], and some include participatory functionalities (e.g. Transcribe Bentham -Causer and Wallace 2012, Monuments to the Dead in France and Belgium 3 ). Given this wide diversity, constructive critical analyses have to be conducted in order to describe and compare existing tools, to suggest avenues for improvement of the functionalities they already offer, or to create new ones. An increasing number of research on social media and crowdsourcing in the cultural heritage domain are already enrolled in this challenge [START_REF] Giaccardi | Heritage and social media: understanding heritage in a participatory culture[END_REF][START_REF] Carletti | Digital Humanities and Crowdsourcing: An Exploration[END_REF]). However, there is a lack of systematic methodological approach allowing to convey such analyses, especially qualitative ones. Then, how should we describe, compare and analyse digital urban heritage tools in a qualitative frame? Our research aim in this paper is to propose a scientific methodology that is:

• systematic, based on a structured group of terms allowing for a comparison that is as objective as possible; • qualitative, in order to highlight the advantages, disadvantages and avenues for improvement of the tools; • multidisciplinary and therefore multi-viewpoint, for proposing thorough analyses of these tools that involve several disciplines, for instance computer sciences and social sciences. Such a methodology moreover meets the scope of heritage studies. It is particularly relevant given the recent standard-setting documents issued by UNESCO (Convention for the Safeguarding of the Intangible Cultural Heritage in 2003, Recommendation on historic urban landscape in 2011) and by the Council of Europe (Malta Convention in 1992, Faro Convention in 2005). These documents put to the fore the inclusion and the participation of local populations and heritage communities, a better knowledge and management of heritage, or the innovation and use of digital tools designed for local contexts but reproducible anywhere in the aim of comparison. These digital tools are supposed to capture both tangible and intangible aspects of cultural heritage, and to go beyond the AHD 4 [START_REF] Smith | Uses of Heritage[END_REF]) by including any kind of cultural heritage, be it official or not. While several scholars have already studied the impacts of such international documents on specific elements of heritage 1 These tools are arrangements of heterogeneous components (technologies, objects, people, methods, practices, etc.) that involve norms and rely on the ability of people to act [START_REF] Marszolek | The National Socialist past and Reconstruction in Postwar German Broadcasting[END_REF][START_REF] Diaz-Bone | Discourses, Conventions, and Critique -Perspectives of the Institutional Approach of the Economics of Convention[END_REF] (Garduño Freeman 2018), there is no methodology allowing the description and comparison of tools, and hence their potential to meet the aims proposed in these documents. How do they articulate digital representation of cities, multimedia data and participatory functionalities? Do these tools really implement citizen participation? Although we do not address all these questions in this article, we propose a methodology that could help in answering them. We more particularly focus on tools that combine at least two of the three following aspects: digital representation of the city (e.g. maps, 3D modelling, etc.), multimedia data (textual data, audio stories, images, videos, etc.) documenting the city and its heritage, and participatory functionalities (comments, forums, submission of multimedia, etc.). These aspects are indeed present in many digital urban heritage tools. In addition, they match the recent standardsetting documents which combine urban heritage, cultural heritage documentation and citizen participation.

In this paper, we firstly examine the existing methods of analysing and comparing digital urban heritage tools. Then we present the process of constructing the methodology DHAL (Digital urban Heritage tools AnaLysis) (section 3.1) before discussing the methodology itself (section 3.2). After that, we propose an implementation of DHAL exemplified on twelve tools (section 4). In this section, we highlight the benefit of this methodology to conduct qualitative analyses on digital urban heritage tools. Finally, we discuss the methodology to point out its advantages and possible future avenues for improvement in section 5 and we finish with an overall conclusion in section 6.

STATE OF THE ART

Several methodologies allowing for the analysis and comparison of digital tools have been proposed in recent years. [START_REF] Alatalo | Two real-world case studies on 3D web applications for participatory urban planning[END_REF] compare 3D web applications for participatory urban planning. Their analysis is based on elements related to technological performance (rendering performance, bandwidth needs, etc.) but also on qualitative elements based on the user experience (ergonomics, response time, etc.). The U_CODE research project [START_REF] Münster | How to involve inhabitants in urban design planning by using digital tools? An overview on a state of the art, key challenges and promising approaches[END_REF] propose a searchable database to analyse thirty participatory urban planning projects conducted by local authorities. [START_REF] Farkas | Applicability of open-source web mapping libraries for building massive Web GIS clients[END_REF] focuses on web-mapping open-source software libraries for creating GIS web clients. He proposes a method of comparing and analysing these software libraries using metrics. [START_REF] Noordegraaf | Modeling Crowdsourcing for Cultural Heritage[END_REF] compare and evaluate crowdsourcing platforms developed by heritage institutions. [START_REF] Ginzarly | Mapping historical urban landscape values through social media[END_REF] analyse photos on Flickr to identify the way in which users (residents and tourists) perceive heritage at the city scale. These methods have the advantage of offering relevant approaches, criteria and indicators. However, they are focused on types of tools that are more specific than those we want to analyse: participatory urban planning [START_REF] Alatalo | Two real-world case studies on 3D web applications for participatory urban planning[END_REF][START_REF] Münster | How to involve inhabitants in urban design planning by using digital tools? An overview on a state of the art, key challenges and promising approaches[END_REF], web-mapping [START_REF] Farkas | Applicability of open-source web mapping libraries for building massive Web GIS clients[END_REF], crowdsourcing [START_REF] Carletti | Digital Humanities and Crowdsourcing: An Exploration[END_REF][START_REF] Noordegraaf | Modeling Crowdsourcing for Cultural Heritage[END_REF], digital tools for citizen heritage [START_REF] Lewi | Visitor, Contributor and Conversationalist: multiple digital identities of the heritage citizen[END_REF]), 3D reconstitution [START_REF] Münster | A Model Classification for 3D Reconstruction in the Context of Humanities Research[END_REF]) and urban landscapes [START_REF] Ginzarly | Mapping historical urban landscape values through social media[END_REF]. Moreover, these methods often stem from the questioning of a single discipline, whereas, following the recommendations of [START_REF] Münster | A Model Classification for 3D Reconstruction in the Context of Humanities Research[END_REF], a multidisciplinary approach is needed in order to offer a more comprehensive analysis. Finally, our goal is to propose a qualitative analysis, whereas most of these methods have the goal of rating tools in order to classify them or to create typologies based on comparing them. Several typologies have been proposed for analysing and classifying participatory digital tools. They reveal that certain indicators are interdependent, such as the choice of tasks and the type of moderation [START_REF] Lewi | Visitor, Contributor and Conversationalist: multiple digital identities of the heritage citizen[END_REF]. They also offer a categorisation according to specific entries. For example, the typology of participatory projects by cultural institutions developed by [START_REF] Oomen | Crowdsourcing in the cultural heritage domain: Opportunities and challenges[END_REF] contains four categories based on the tasks proposed to contributors (correcting, transcribing and contextualising; completing, collecting and categorising; crowdfunding; and cocuration). Taking the specific case of crowdsourcing, Ridge (2013) deepens these tasks and evaluate them in order to propose a more efficient citizen participation leading to data of better quality. The typology of [START_REF] Lewi | Visitor, Contributor and Conversationalist: multiple digital identities of the heritage citizen[END_REF] is composed of three categories (curated sites, content-hosting site and social networks) based on the contributors' involvement in the functioning of the tool. Wiggins andCrowston (2010, 2014) are the only ones who propose a very complete typology of citizen science projects -be they digital or not. However, the typologies are relative to a specific type of tools that are unconnected to digital heritage. This examination of existing methods shows that each of them can contribute to the collection of indicators that we want to establish. However, none of them is adequate by itself for attaining our objective of systematic, qualitative, and multidisciplinary analysis of urban digital heritage tools. In order to meet this need, we present a new methodology in the following sections: DHAL.

DHAL, A METHODOLOGY FOR DESCRIBING, ANALYSING AND COMPARING URBAN DIGITAL HERITAGE TOOLS

METHODOLOGY FOR CONSTRUCTING DHAL

DHAL is made up of a collection of indicators5 allowing for the detailed description of tools combining urban data, multimedia data and participatory functionalities (Figure 2). We have grouped these indicators into categories6 and sub-categories7 that we present in the following sub-section (Table 1). The construction of the indicators and their grouping stems from an iterative process depicted in Figure 1. Four stages compose this process: i. Formalising of indicators, ii. Tests on tools, iii. Comparison with standards and typologies, and iv. Comparison with field work. In order to refine the categories and indicators and to make this integrated approach more consistent and as complete as possible, we have iterated through these stages several times.

FIGURE 1 -PROCESS OF CREATING DHAL

DHAL's construction in stages joins several sources. Firstly, it is based on the description and analysis of existing tools. Because of their diversity, they indeed implement many different methods and functionalities. Analysing them hence has a heuristic function for establishing indicators (e.g., richness of content presented in detail in section 4) in the objective of proposing a systematic analysis methodology. We selected and analysed fifty-four tools (presented in the appendix) that matched the three aspects of interest (digital representation of the city, multimedia data documenting the city and its heritage, and participatory functionalities). Most of the fifty-four tools have been developed in France. This choice has been made for several reasons. Firstly, our project takes place in France, and we wanted to compare our tool to other existing ones (cf. section 4). We indeed make the hypothesis that participative and heritage traditions vary from one country to another8 , and then influence the way to implement them in digital tools. However, thirteen of the fifty-four tools are foreign or international, which broadens the scope of our analysis and allows to compare the differences. In addition to have a heuristic function for establishing indicators, this step brought us to generalize and categorise the indicators (Figure 2). The indicators and categories that emerged with the analysis of existing tools have been seen in the context of existing standards and typologies. A large number of methods indeed rely on description norms and standards such as CIDOC-CRM [START_REF] Doerr | The CIDOC CRM -An Ontological Approach to Semantic Interoperability of Metadata[END_REF][START_REF] Araújo | Annotated documents and expanded CIDOC-CRM ontology in the automatic construction of a virtual museum[END_REF][START_REF] Messaoudi | An ontological model for the reality-based 3D annotation of heritage building conservation state[END_REF] and Dublin Core [START_REF] Weibel | The Dublin Core: a simple content description model for electronic resources[END_REF][START_REF] Kakali | Integrating Dublin Core metadata for cultural heritage collections using ontologies[END_REF][START_REF] John | Representation and Visualization of Urban Fabric through Historical Documents[END_REF]. In order to make the analysis of tools easier and to improve interoperability with tools and other analysis methodologies, we made the choice of relying on standards and typologies when possible. In this way, some of DHAL's indicators stem directly from CIDOC-CRM and Dublin Core or are equivalents found after the fact in these standards (see CIDOC and DC respectively in Figure 2). For instance, we have replaced "temporal dimension" of the urban data with time-span 9 from CIDOC-CRM and "proposed media" with relation10 from Dublin Core. Typologies of citizen science tools allowed us to add indicators such as contributors' interests and motivations, the timing of participation (when), and certain objectives of the tools. We also carried out a field work (interviews and workshops) among people and organizations involved in cultural heritage (public institutions, local cultural heritage associations and citizens) in Lyon, France. This field work lead to the addition of indicators relating to accessibility and visibility and to the ways of contributing content. Moreover, as the methodology was constructed in an academic setting, it seemed essential to us to focus on the thoughts on the tool, whether internal or external, particularly in order to improve it. Finally, the methodology has been built with a multidisciplinary approach, especially in computer science and social sciences. We indeed believe it is important to have a multidisciplinary approach in constructing such a methodology as the tools analysed stem from different disciplines and domain of expertise. Hence, certain indicators come from the field of social science, especially those that imply a qualitative investigation of what users do with the tool (e.g. required skills, modes of resistance11 ). Others, such as those related to the content and its mode of representation, come from computer sciences. In a similar fashion, some categories such as objectives and thoughts on the tool are more related to research issues in the social sciences, while others, such as content and navigation in content are more related to computer sciences. The confrontation of the disciplines led to refine and harmonize the indicators both at the vocabulary level (discussions on the distinction between information and content, multimedia and data, system and tool, etc.) and at the level of their usefulness (explaining the relevance of certain indicators that were not immediately clear for researchers in another discipline). Thus, in addition to being a methodology, DHAL has a heuristic function in the implementation of scientific plurality and illustrates the need to work conjointly across disciplines.

PRESENTATION OF THE METHODOLOGY

The methodology DHAL is made up of a collection of indicators that allows users to describe and compare digital urban heritage tools. These indicators stem from the phase of the methodology's construction presented in section 3.1. In order to facilitate understanding and use of DHAL, we have organized these indicators according to seven categories presented and described in Table 1. The proposed methodology DHAL (containing the categories, sub-categories and indicators) is presented in Figure 2 as a mind map. The mind map format offers both better readability and easier use of DHAL. For example, it allows to describe and analyse systems by navigating in the branches (i.e. the categories and sub-categories) and to omit the branches that correspond to an aspect not managed in the tool being analysed. In this way, in the case of a non-participatory tool, it is possible to remove the branch contributing content -i.e. the branch related to describing the participatory aspect of the tools.

Category of Indicators (7) Description

General Information

Describing the people involved, the activity period of the tool, the economic model, the type of heritage represented, the theme (urban, architectural, industrial, etc.), the target and actual audience or the impacts and consequences related to the tool.

Objectives

Describing the tool's objectives (promoting, collecting, informing, etc.)

Thoughts on the tool

Describing thoughts on the tool, whether they are academic or professional (internal or external) or participatory (how and at what stages of the project).

Content

Describing urban and multimedia data and any additional content, in terms of type, quantity, spatial and time-span, etc.

Navigation in content

Describing the modes of access to multimedia (presented as a list or as hotspots, organization, display modes) and navigation in data content (spatial, temporal, or thematic). This category also allows for describing possible additional functionalities, such as gamification.

Contributing content

Describing who participates, how (methods implemented for allowing and/or encouraging participation, appropriation of modes of participation by contributors, etc.), when (limited or unlimited duration of participation), and why (interests and motivations for participation).

Other indicators address the methods of moderation and indicate the presence of a policy charter for participation.

Visibility and accessibility

Describing the methods established to make the tool visible and accessible. The name of the tool, the indicators relating to media and the press, and the sharing functionalities (the participants sharing their actions) are mainly related to the tool's visibility while the other indicators are related to its accessibility. In the following section, we present a qualitative analysis of twelve tools using DHAL. In the interest of concision, we do not present the analysis according to all the indicators but have selected only some in each category.

IMPLEMENTATION OF DHAL

We have chosen to implement DHAL in the context of the Fab-Pat research project12 . This project brings together researchers in both social science and computer sciences along with specialists working in the museums, libraries or heritage offices of the city of Lyon (France). One of the objectives of this project is to propose a digital tool to allow heritage professionals and nonprofessionals to meet and discuss what Lyon's heritage is. In order to do this, we are developing a tool for representing digital cities in 3D, with a temporal dimension representing its evolution in time, and that can be enhanced with multimedia data documenting the city that can be added in a participatory way. DHAL is of use in the building process of this tool. It indeed allows to assess existing digital urban heritage tools in order to provide insights on functionalities and methods for representing cultural heritage and creating and sharing knowledge.

We selected twelve tools to illustrate the implementation of DHAL on this specific use case -the Fab-Pat research project. Our selection was guided by the needs of this project and its main questionshow to articulate urban and multimedia data, how does participation look like in similar tools? For instance, among the twelve tools, five have participatory functionalities. Four are virtual 3D tours that display multimedia objects using various modes of interaction. Six offer geolocation of cultural heritage. As a consequence, analyses arising from the implementation do not pretend to any exhaustiveness nor to reflect the diversity in digital urban tools. In addition, we remind that DHAL is adaptable to the needs and questions of its users. We then only propose one possible implementation on a specific use case, but any user is free to refine the indicators, or to choose other ranges than we did. Section 5 addresses some possible other implementations of DHAL.

The general information gives an overview of tools. The twelve tools are available for free. They have been created between 2003 and 2015. Some of the oldest have been improved through time and according to financing: they added participatory functionalities, they extended their spatial coverage, they developed versions for Smartphones, etc. Except those downloaded on Smartphones, they all need an Internet access to be used. In terms of types of heritage, most tools present some element of official heritage (AHD) and five present memorial or unofficial heritage. Out of these five tools, one (3 13 ) is interested only in unofficial heritage, one (9) only in official heritage and three (10,11,12) are interested in both official and unofficial heritage. It should be noted that the integration of participatory functionalities seems to go hand in hand with openness to less official heritage, either because the desire of the stakeholders is to bring this out, or because this is naturally what the contributors add. Within these types, tools generally present a main theme: urban and/or architectural heritage, and archival heritage. We noticed an absence of rural heritage. Finally, the twelve tools involve various actors. There is a wide range of stakeholders: associations, local authorities, private digital companies, public organisations, universities and research committees. These are those in charge of a tool. One has to notice that a partnership between a university and public organisations -as it is the case for the Fab-Pat project -is not at odd. These stakeholders may develop themselves their tool or they may rely on a service provider to develop their software (1,2,4,5,7,9,10,11). Among the four tools involving a university or a research (3,4,8,11), two called upon a service provider for software development (4,11), which implies that no computer science laboratory was involved -contrary to the Fab-Pat project -but that the tool involved only researchers in social sciences fields (which is confirmed by the list of partners). Finally, it should be noted (and verified in considering a larger number of tools) that no tool involving a collaboration between disciplines experienced failure. These stakeholders lastly depend on public funding (3,4,5,8,11).

A second category of indicators relates to the objectives -which may be numerous -of a tool. In Figure 3, the participatory tools are represented in light grey and the non-participatory tools are represented in black. Objectives indeed take an interesting turn when they are related to the participatory dimension. Collecting documents and information is clearly the purpose of participatory tools (3,6,11,12), but they are not limited to this, since they most often also have objectives of sharing (3,6,12), creating social connections (3,9,12), and mobilising users (3,6,12). Nonparticipatory tools encourage a different mediation of heritage (1,2,4,5,7,8) and opening and encouraging use of archives and heritage (1,2,7,8). Out of the four tools with a research objective (3,4,8,11), two are participatory (3,11) and two are not (4,8). The latter group mainly aims to compare 3D reconstructions to scientific knowledge. Finally, it is interesting to note (and to identify using DHAL) that a planned objective may not be attained and that an objective that was not initially planned may emerge as the tool is used. For example, a tool that had the objective of collecting and promoting data can lead to the creation of social connections even though this was not one of its initial goals (for instance 11). The content of the tools in terms of urban data can be of different types: 2D map (3,5,6,7,8,9,10,11,12), panoramic pictures (1,2,4), or 3D models (2,3,8). It is also interesting to note that some tools offer multiple modes of representation of urban data (3D models and 2D maps, for example) that can serve different uses. For instance, a 3D model for the reconstruction of a monument and a 2D map to specify its geolocation on a larger map. Correlating the type and coverage indicators shows that the tools offering a 3D model (2,8) have relatively limited coverage (limited to a monument) -while the Fab-Pat tool allows to manage digital 3D models of cities. This mode of representation is especially used for virtual tours of buildings that have been reconstructed in their prior condition. Finally, most tools limit the time-span of their digital urban model to a specific yearwhile the Fab-Pat tool intends to propose a wider time-span with digital modelling of specific states of parts of the city in the past. Time coverage of multimedia data is however wider, as these data are generally more accessible than 3D models for instance. Moreover, some tools (1,4,6,7,8,10,11) aim to collect these multimedia data related to the past -as it is the case for the Fab-Pat tool. The metadata associated with this multimedia vary. One tool (2) offers no metadata, seven (1,3,5,6,7,8,9) offer only three or four (name, date, description, creator), three (4,11,12) add more specific information (architectural movement, date of destruction, conflicts involved) and one (10) leaves the user free to add metadata. In the case of participatory tools, the metadata is generally linked to the mode of participation used. If the submission is open to every contribution, little metadata is required which generally implies that the data will be less structured. Finally, tool can be qualified using the richness of content indicator, which is composed of three categories:

• Basic (2,6,9): the content includes text, current photos, and little metadata. Content is presented as photo slideshows and hotspots providing information on points of interest. • Intermediary (1,3,4,5,7,11,12): in addition to the basic content, there are audio files, archival photos, maps, and a great deal of metadata. • Advanced (8,10): in addition to the intermediary content, there can be videos, audio-guides with geolocation information, or comic strips. The modes of representation can allow for temporal comparison (comparison of photos of the same area at different dates for instance). In the category navigation in content, access to multimedia mainly occurs through a presentation in the form of lists (1,3,4,5,6,8,10,11,12) or using geolocation on the tools' urban models (1,2,3,4,6,7,8,9,10,11). Three tools (4,6,7) offer organisation by theme or era. Thematic navigation of multimedia (e.g. access to medias through semantic information or through common themes) is very frequently present in the twelve tools. Seven of them (3,5,6,9,10,11,12) offer keyword search in the title and associated metadata, only two (4,5) contain direct relations between multimedia, and six (3,4,6,7,9,10) offer thematic grouping of multimedia (e.g. medias related to themes such as architecture, history, etc.). One tool offers adding tags defined by users, allowing navigation through the multimedia. Temporal navigation in data is rarely possible or is limited to a few dates (1,4,8,12). Only three tools do not propose spatial navigation. Other propose camera rotations (1,2,4), guided or semi-guided moves (1,3,10) and free moves (6,7,9). Most tools allow a geolocation search by clicking on geolocated points of interest. Both spatial and temporal navigation have to be improved -as intended in the Fab-Pat tool -by, for instance, implementing a continuous navigation in urban and multimedia data in space and in time. Finally, four tools (5,8,9,10) offer gamification mechanisms. For three of them (5,8,10), this takes place as games (quizzes, etc.) and for the remaining one (9), by mechanisms for participation compensation (change of status, etc.). These mechanisms are all used in participatory tools that have been successful. In terms of contributing content, seven tools are not participatory (1,2,4,5,6,7,8): only the administrators can add or modify content. In the five others (3,9,10,11,12), users can also contribute in various ways (Table 2): adding content, interaction with content, or interaction among users. tool and two (3,5) on a dedicated website. Most tools are accessible from many other sites via links (1,2,3,4,5,7,8,9,10,11). However, only half of them (4,7,9,10,11,12) are associated with other digital communication interface such as Facebook,Twitter,or Instagram. Moreover,nine (2,3,4,5,6,7,8,9,11) are accessible in only one language (French or English), while three (1,10,12) offer at least two (French, English, German, etc.). Finally, half of the tools (1,3,7,10,11,12) offer a tutorial to explain how to use them. This implementation of DHAL allows to relate the Fab-Pat tool to similar ones in terms of urban data, multimedia data, and participative functionalities. It then underlines specificities of the Fab-Pat tool. For instance, it states its innovative aspect by willing to articulate a 4D (3D and time) digital models of cities, multimedia data related to the past, and the participation of citizens for enhancing the digital model with these multimedia to share and build urban cultural heritage. Moreover, although its community of actors (stakeholders, software developers, funders) and its objectives are by no way new, it is based on an academic multidisciplinary approach going from social sciences to computer sciences, which is not always the case in the tools analysed. It also intends to propose a continuous navigation among urban and multimedia data through time at the scale of a neighbourhood, or a city. A combination of these aspects seems quite new in comparison with the tools analysed. It finally relies on various thoughts, descriptions and comparisons about what works or not in terms of citizen participation, which allows to propose the best participative functionalities. Consequently, this tool could perfectly meet the aims of international documents in terms of citizen participation, development of digital tools, or interest for unofficial heritage. Beyond its implementation for the Fab-Pat project, DHAL also turns out to be useful in a wider analysis of tools. It indeed shows that aspects not thought when creating a tool can be brought to the fore when using it. For instance, objectives of tools are generally extended depending on the appropriation of the users. Hence, the common computer science approach consisting in proposing adaptable tools based on adjustable software components makes perfect sense. In addition, it sometimes shows lacks regarding some functionalities. For instance, while thematic navigation in multimedia is often managed, spatial and temporal navigation are not always the first concern of administrators while it might enhance possibilities in sharing cultural heritage and knowledge. A possible explanation might be that data is missing or not always available to properly cover these aspects. One might also argue that managing spatial navigation in 3D with a diachronic dimension is still a hot topic of investigation in computer sciences and that it asks for a lot of resources to be implemented.

Discussion of DHAL

In addition to DHAL's usefulness for the Fab-Pat project, several advantages emerged during its construction and implementation. First of all, the variety of indicators allows for a thorough and specific view of the tools analysed. The use of DHAL thus leads to an overall view of the tools that is more significant than using typologies and other methods presented in section 2. Next, the analysis can be refined by relating indicators to each other as shown in section 4. For example, it is possible to gather elements regarding a tool's success by comparing indicators such as target audience and actual audience, by focusing on impacts and consequences (e.g. certification, prizes, number of downloads or views, etc.) and, in the case of participatory tools, by looking at the number of multimedia files contributed by users outside the circle of administrators. Finally, formalising the indicators of DHAL allows us to make timely discoveries regarding the functionalities of certain tools.

All these opportunities offered by using DHAL allow for a qualitative analysis of tools, which can help when studying them or when constructing new ones (as in the case of Fab-Pat). DHAL can also be used to conduct a quantitative analysis of tools. After having defined specific objectives, it is possible to assign a weight to the indicators. For example, the need to find a fun participatory tool can lead to grant more weight to the indicators gamification, mode of compensation, and interaction with content. This use of DHAL allows for rating tools in order to classify them, the highest-ranked being the one that meets the predefined needs the best overall. To go a bit further, it is also possible to make certain indicators (or categories) discriminating. An indicator (category) is discriminating if a tool with a score that is zero or that is below a certain threshold for this indicator (category) therefore receives an overall score of zero so that it is placed at the bottom of the classification. For example, if one of the needs is the participatory aspect, then the category contributing content can become discriminating. Thus, if a system has a score of zero for this category, its overall score will be zero. This kind of quantitative analysis can be useful in particular for classifying tools in order to select the one that is most appropriate to specific needs. A possible improvement concerns defining ranges for the values of indicators. These are indeed defined according to one's specific needs and on the basis of the characteristics of the tools analysed. For example, coverage of urban data includes in our case monument, area of a city, city, country, and world. However, this list can create problems. For example, how should we categorise a multi-scale tool that represents both monuments and a city? We made the choice of classifying the tool in the category of the largest area that it represents. This list could also be different for other types of tools, such as those related to rural areas with values such as municipal territory, natural countryside, etc. We hence let the user define its own ranges, based on the explanations and examples given in this article. However, providing some predefined ranges could be an enhancement for the future. In order to refine the indicators, it may also be relevant to detail those related to impacts and consequences (number of downloads, certifications, prizes, user notes) by relying on the metrics proposed by [START_REF] Farkas | Applicability of open-source web mapping libraries for building massive Web GIS clients[END_REF]. We could also detail those related to interaction among users: while we have mentioned those that take place online, those that may take place offline or in another digital space are absent. This is also the case for interaction with content, which can consist in correcting, transcribing, localising, describing, etc. We did not carry out this subdivision due to our objective of general description of the tools. However, indicators may be refined depending on the type of tools analysed and on specific analysis needs. Hence, DHAL provides structured guidelines in the form of indicators and categories for analysing digital urban cultural heritage with a systematic, qualitative and multidisciplinary approach. Finally, the implementation of DHAL showed that some indicators might be difficult to fill out. For instance, it is necessary to know well the tools analysed in order to find information about target audience, actual audience, modes of resistance, and motivations and interests of contributors 14 . One might indeed need to conduct a qualitative investigation of users of the tools to fill out these indicators.

CONCLUSION

There is a growing number of digital tools for representing and interacting with cultural heritage. The methodology DHAL proposed in this paper contributes in filling a gap for comparing and analysing these tools. Its structuration according to categories and indicators originating from several sources and with multidisciplinary point of views allows for a systematic, qualitative and multidisciplinary approach. It focuses on tools articulating at least one of these aspects: digital representation of cities, multimedia data documenting heritage and participatory functionalities to add multimedia data. This methodology and its multiple uses then fits recommendations made in international standard-setting documents produced by UNESCO or the Council of Europe, and might be useful to implement better citizen participation, better knowledge, and better management of heritage, be it official or not. We presented one of its possible uses by implementing it on twelve tools selected according to their relevance in the context of the Fab-Pat project. This implementation shows that it is useful for comparing a tool to other existing tools in order to gather information about methods and functionalities allowing for the representation and sharing of cultural heritage knowledge. In addition to allowing relevant qualitative analyses, DHAL also allows for implementing a multidisciplinary approach, both for its creation and for its usage. Finally, it underlines features of tools that are not always thought or that raise issues in computer and/or social sciences, in terms of participation or spatial, temporal and thematic navigation. We believe that these aspects should be further developed in the future in order to better articulate digital representation of cities, multimedia data and participatory functionalities. If tools could be further developed, so do DHAL. We proposed a version of DHAL with structured guidelines that any user of the methodology can adapt to his objectives. In that way, DHAL is a flexible methodology. Among other, it could be used for quantitative analyses, which we have sketched out in section 5. Finally, it might be interesting to propose an associated software easing the use of DHAL and allowing an automatic comparison of the tools once they have been analysed with DHAL. We then invite researchers in various disciplines, and practitioners, to use DHAL and to improve it according to their needs.

FIGURE 3 -

 3 FIGURE 3 -OBJECTIVES OF THE TOOLS. THE PARTICIPATORY TOOLS ARE REPRESENTED IN LIGHT GREY AND THE NON-PARTICIPATORY TOOLS ARE REPRESENTED IN BLACK

  This is the dominant discourse in the variety of discourses on heritage. Stemming from the Western world, it is a professional discourse that creates a hierarchy of values attributed to heritage, defines what heritage is according to standardized procedures (especially creating lists), and distinguishes good and bad heritage practices. UNESCO and ICOMOS, as well as many national institutions, express this discourse.

	).
	2 http://www.environment.gov.au/cgi-bin/ahdb/search.pl [Last accessed: 07/2019]
	3 https://monumentsmorts.univ-lille.fr/ [Last accessed: 07/2019]

4

TABLE 1 -

 1 INDICATOR CATEGORIES AND DESCRIPTIONS

FIGURE 2. REPRESENTATION OF THE METHODOLOGY DHAL AS A MIND MAP MADE UP OF 7 CATEGORIES (BRANCHES) AND INDICATORS (LEAVES). THE TERMS DC AND CIDOC MEAN THAT THE TERM USED FOR THE INDICATOR COMES FROM DUBLIN CORE OR CIDOC-CRM RESPECTIVELY

In italic in the following.

In bold in the following.

Underlined in the following.

Several scholars underline the difference between France and Great-Britain in terms of heritage[START_REF] Vecco | A definition of cultural heritage: From the tangible to the intangible[END_REF][START_REF] Rautenberg | Industrial heritage, regeneration of cities and public policies in the 1990s: elements of a French/British comparison[END_REF]) and citizen participation[START_REF] Huxley | Administrative Traditions and Citizen Participation in Public Policy: A Comparative Study of France, Germany, the UK and Norway[END_REF].

See definition of time-span page 26 of the current official version (6.2.3) of CIDOC-CRM, accessible here: http://www.cidoc-crm.org/sites/default/files/2018-05-16%23CIDOC%20CRM_v6.2.3_esIP%28XDP%29%28XM%29.pdf [Last accessed: 07/2019]

http://dublincore.org/specifications/dublin-core/dcmi-terms/2012-06-14/?v=elements#relation[Last accessed: 07/2019]

Resistance can take the form of not using the tool, misusing it, or not respecting standards and policy charters.

http://imu.universite-lyon.fr/bilan-2016/fabpat-sharing-the-shaping-of-heritage-approach-and-issuesconcerning-the-historical-urban-landscape-hul-2016/ [Last accessed: 07/2019]

 13 The twelve tools analyzed in this section are numbered in the table of the Appendix.

Concerning motivations, we refer readers to the extensive literature on the subject[START_REF] Coleman | Volunteered Geographic Information: The Nature and Motivation of Produsers[END_REF][START_REF] Arends | Analyzing user motivation in an art folksonomy[END_REF].

Acknowledgements

This work was supported by the LABEX IMU [ANR-10-LABX-0088] of Université de Lyon, within the program 'Investissements d'Avenir' [ANR-11-IDEX-0007] operated by the French National Research Agency (ANR). We would like to thank Benjamin Saurel for his initial work on this research.

Contributing content: how

Adding content creating a file or a collection 4 (3,10,11,12) adding multimedia documents 2 (3,11) Interaction with content modifying 1 (12) commenting 3 (3,9,10) rating 1 (10) sharing 1 (9)

Interaction among users comment tools 4 (3,9,10,12) discussion page 1 (12) TABLE 2 -WAYS OF CONTRIBUTING CONTENT Additions and interactions occur in following norms. First of all, the five participatory tools require the identification of the contributor by signing in (3,9,10,12) or providing an email address (11) when the contribution is made. The contributors only rarely benefit from compensation by a change in status (9). The form of contribution is most often guided -i.e. structured with required fields to fill out (title, description, localisation, etc.) while others are optional (date of construction or modification, architect, etc.). In the case of four tools (3,10,11,12), contributors can get help from a tutorial that explains how to contribute, and they must observe a policy charter (9,10,12) that regulates, for example, discussion in the comments section. Three tools also have visible moderation.

In the case of pre-moderation (11), any new content to be added must be validated by administrators before becoming public. It should be noted that the only tool that proposes only adding content, with no possibility of interaction, is also the only one that has pre-moderation. With post-moderation (9,10), content that is not compliant may be removed after having been made public if it is flagged by a user. Contributors participate only in the context of the use of the tools and not in its construction. However, they can take part in thoughts on the tool, either by giving it a rating (10), or by making contributions to new versions (9,11). In this way, in terms of participatory thinking, elements (particularly blog posts) lead us to believe that discussions took place regarding the use of the tool and that modifications were made following these discussions. Professional or academic thoughts concerns only three tools (3,8,11) whose development is accompanied by either scientific papers or a blog managed by academics reporting on the project's progress.

Visibility and accessibility are based on certain characteristics, such as the name of the tool which may or may not facilitate its search engine optimisation. Eight tools have a text with a presentation of the tool or even of the project that they are part of. Six (4,6,7,10,11,12) are presented directly on the

Appendix: List of 54 tools analysed

The following table lists the tools used for constructing DHAL (section 3.1). The tools in bold are the twelve selected for implementation (section 4).


Rabab Boyaala

Marie Peng

Wun-Shan Tai

Rachid Touzani

Thierry Roisnel

Vincent Dorcet

Yun Chi

Véronique Guerchais

Henri Doucet

Jean-François Soulé

Exploiting the Reactivity of Fluorinated 2-Arylpyridines in Pd-Catalyzed C-H Bond Arylation for the Preparation of Bright Emitting Iridium(III) Complexes

Keywords:

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

The design and synthesis of cyclometalated iridium(III) complexes has focused much interest for their applications in electroluminescent devices due to their intriguing luminescent behavior, i.e., long-lived excited states, high luminescence efficiencies, and facile color's tuning by ligand design. 1 Typically, bis-cyclometalated ppy-based (ppyH 2phenylpyridine) neutral Ir(III) complexes of the type [Ir(C^N) 2 (L^X)] (where C^N and L^X are cyclometalated ligand and monoanionic ancillary) were employed as dopants in organic light-emitting diodes (OLEDs), 2 while their cationic congeners [Ir(N^C) 2 (N^N)]PF 6 (N^N is a di-imine ligand) were used in light-emitting electrochemical cells (LEECs). 3 A plethora of charge-neutral and cationic phosphorescent Ir-ppy based complexes displaying emission ranging from red to blue have been reported to date, their synthesis and photophysical properties being well-documented in the literature. 4 Numerous chemical modifications allowing the control of the emission energy have been reported. For instance, in the case of the neutral iridium(III)bis [(4,6-difluorophenyl)-pyridinato-N,C2']picolinate FIrpic, A (Figure 1), the most studied bis-cyclometalated iridium complex, 5 introduction of strong electron-withdrawing substituents such as perfluorocarbonyl, 6 benzoyl 7 or diphenylphosphoryl 8 groups (Figure 1, complexes B-D) onto the phenyl ring at the C5position allows to further blue-shift the emission, whereas CF 3 -Firpic 9 (F1, Figure 1) derivative incorporating an electron-withdrawing substituent at the 5-position of the pyridine ring of dF-ppy displays a bathochromic shift of the emission when compared to the parent unsubstituted complex. Adding electron-withdrawing or-donating substituents on the C^N ligand is a traditional way to modify the electronic structure of resulting complexes, and hence the color of the emission. On the contrary, the emission energy is not subject to change when adding sterically bulky aryl substituents at the 4-position of the pyridine ring of the C^N-ppy ligand, the attainment of a coplanar conformation between the two aromatics is inhibited leading to a disruption of the conjugation. 3h, 10 This ligand design has been applied for both charge-neutral and cationic bis-cyclometalated complexes, and the decrease of the intermolecular interactions, due to steric hindrance, has led to the most successful complexes with improved device performances. In a synthetic point of view, it is worth-mentioning that in all cases, aryl-appended pro-ligands of dFppyH, were prepared, prior to metal complexation, using classical Suzuki carbon-carbon cross-coupling reactions. To facilitate the access to a large variety of complexes with tunable photophysical properties, we have developed the late-stage modification of fluorinated 2-arylpyridines and 2-arylquinolines, which allowed us to build a library of nitrogen-based pro-ligands in only one-step. 11 Our approach was based on regiodivergent metal-catalyzed C-H bond arylations. We showed that in the presence of palladium catalysts, the C-H bond arylation occurred at the adjacent position of the fluorine atoms while using a ruthenium catalyst, the ortho-C-H bond of the pyridine or quinoline rings is the selective site of functionalization. Moreover, the corresponding cationic iridium(III) complexes [Ir(C^N) 2 (N^N)]PF 6 featuring these synthesized p-CF 3 -C 6 H 4appended C^N-ligands (see for instance, complex E, Figure 1) display an increased photoluminescence quantum yield, compared to the unsubstituted complex. 11 Interestingly, the emission band is not affected by this chemical modification, as already observed for the related series of iridium(III) complexes where the substitution is achieved at the 4-position of the pyridyl ring. 10e, 12 The color of the emission depends on the C^N ligand, i.e., the position and number of the fluorine atoms as well as the nature of the nitrogen-based (pyridine or quinoline) ligand. Complex E displays a bright luminescence in the green region (λ em = 525 nm) of the visible spectrum. The nature of the substituent of the incorporated aryl group on the photophysical properties was not investigated at this time, as well as the substitution on the pyridine ring. Only, the para-trifluoromethyl-substituted bromo derivative p-CF 3 -C 6 H 4 Br was used as the reagent, the first catalytic step of oxidative addition being facilitated, in order to establish the best catalytic conditions for both Pd and Ru catalytic systems. In order to further explore the scope of this reaction, we decided to investigate Pd-catalyzed C-H bond arylation 13 of dF-CF 3 ppy derivatives using various bromoaryl reagents. Fluorobenzene derivatives are generally very reactive substrates in Pd-catalyzed C-H bond arylation, 14 because fluorine atoms often enhance the reactivity of the adjacent C-H bonds owing to their electronic properties, leading in most cases to site selective reactions. 15 However, 2-(difluorophenyl)-5-(trifluoromethyl)pyridine (dF-CF 3 ppyH) derivatives are more challenging substrates in terms of regioselectivity as the presence of the electron-withdrawing 5trifluoromethyl substituent on the pyridine ring could also enhance the reactivity of the adjacent C-H bond, 16 which could lead to side reactions.

In this report, we extend our catalytic approach to prepare two families of Ir(III) complexes, neutral (F 9 ) and cationic species (G 17 ) (see Figure 1

5.

Herein, we report the synthesis, the X-ray crystal structures, and the solution-state photophysical properties of (i) a family of 2-picolinato complexes of the form [Ir(Ar-dF-CF 3 ppy) 2 (pic)] F and (ii) a series of positively-charged complexes [Ir(Ar-dF-CF 3 ppy) 2 (dmbpy)]PF 6 G having a 4,4'dimethyl-2,2'-bipyridine ancillary. This will allow us to evaluate the role of the added aryl substituent at the cyclometalated difluorinated phenyl ring of the C^N ligand on the photophysical properties by comparison with the unsubstituted analogues (F1 9 /F5 and G1/G5, Schemes 2 and 3) used as reference complexes. 14 We also show that the color of the emission can be fine-tuned by changing the position of the fluorine atoms in both series of complexes (F1-4 vs. F5-6 and G1-4 vs. G5-6, see Schemes 2 and 3), from blue to blue-green. Having synthesized the new pro-ligands 1-6 in pure form via Pd-catalyzed C-H bond arylation, we turned our attention to the preparation of charge-neutral iridium(III) complexes F, CF 3 -FIrpic congeners of F1 (Scheme 2). The cyclometalated iridium μ-chloro-bridged dimers [(C^N) 2 Ir(μ-Cl)] 2 were prepared using a classical procedure which consists of a treatment of IrCl 3 •3H 2 O with 1-6 in a mixture of 2-ethoxyethanol and water at 125 ºC for 24h. Then, the crude dimer was treated, without any purification, with 2-picolinic acid in the presence of sodium carbonate in 2-ethoxyethanol at 125 ºC over 24h to afford the nonarylated reference complexes F1 9 and F5 bearing a different difluoro phenyl substituted (4,6difluorophenyl and 3,5-difluorophenyl, respectively) cyclometalated ligand and the corresponding arylated complexes F2, F3, F4 and F6 featuring a biaryl unit. The novel complexes F2-F6 were characterized by 1 H-NMR, 13 C-NMR, and 19 F-NMR spectroscopy and high-resolution mass spectrometry (HRMS) (Synthesis details in SI).

RESULT AND DISCUSSION

Synthesis

Scheme 2. Preparation of Complexes F1-F6 with Pyridine-2-carboxylate as Ancillary Ligand

The second family of cationic iridium complexes [Ir(C^N) 2 (N^N)]PF 6 (G) was prepared using again the fluorinated 2-arylpyridine pro-ligands 1-6, 4,4'-dimethyl-2,2'-bipyridine being used as the diimine ancillary ligand following the reported two-step procedure (Scheme 3). 11 Complexes G1-G6 were isolated in 64-74% yields as yellow air-stable solids, and were characterized by NMR spectroscopy and high-resolution MALDI mass spectrometry. The complex G1, prepared from non-arylated 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine has been previously employed as a catalyst in photocatalytic water reduction, but there was no studies devoted to its luminescent properties. 18 Scheme 3. Preparation of Complexes G1-G6 with 4,4'-Dimethyl-2,2'-bipyridine as Ancillary Ligand.

X-ray Crystal Structures. Single crystals of F2, F5, F6, G3, and G5 suitable for X-ray analysis were grown by slow diffusion of hexane into a CH 2 Cl 2 solution of the respective complexes. The X-ray crystal structures of the neutral complexes F2, F5 and F6 and the cationic complexes G3 and G5 are depicted in Figure 2. Selected bond distances and bond angles as well as selected bite angles are tabulated in Table 1. All complexes, neutral and cationic, exhibited distorted octahedral geometries, with the two C^N ligands adopting a C,C-cis, and N,N-trans configuration, similar to that of the archetype complexes. 4a, 5e For neutral complexes, the oxygen atom of the picolinate ligand is located trans to the C-ligand, as found in the precursor complex F1. 9 The Ir-C and Ir-N bond distances in F2 are in the same range to those of the unsubstituted complex F1. The average Ir-N (2.052 Å) and Ir-C (2.019, Å) bond distances in the C^N ligands of F6 are longer that those observed for the 2- (4,6difluorophenyl)pyridinato derivatives F1 and F2. The aryl pendant is not coplanar with the C^N ligand, the torsion angles between the plane of the incorporated aryl group and that of cyclometalated phenyl ring of the two C^N ligands, are 64.30(4)° and 46.20(4)° and 68.20 [START_REF] Bünzli | Exceptionally Long-Lived Light-Emitting Electrochemical Cells: Multiple Intra-Cation π-Stacking Interactions in [Ir(C^N)2(N^N)][PF6] Emitters[END_REF]°/61.40 [START_REF] Ackermann | Transition-Metal-Catalyzed Direct Arylation of (Hetero)Arenes by C-H Bond Cleavage[END_REF]° for F2 and F6, respectively. For cationic complexes, the average Ir-Cppy (2.021 Å) and Ir-Nppy (2.053 Å) bond distances of G5 are elongated, with respect to those in complex G3. The added aryl group in G3 displays a similar twisted conformation observed for F series of complexes: the plane of the aryl ring relative to that of the Cconnected phenyl displays dihedral angles of 61.30(8)° and 53.00(9)°. Importantly, the distance between two iridium centers for adjacent complexes in the crystal packing varies slightly from 8.150 Å (F1) 9 to 9.044 Å (F2) while a more significant increase is observed going from F5 to F6, (9.917 Å to 14.157 Å). Notably, G3 exhibits the longer intermetallic distance of 15.034 Å, longer than that found for G5 (10.080 Å) showing the dramatic influence of the presence of the bulky p-C(O 2 Et)-C 6 H 4 group in this case. This distance is significantly greater than to the maximum values reported for the related 4-substituted pyridine cationic complexes which do not exceed 11 Å. 12 These results illustrate the impact of the location (phenyl vs. pyridyl rings of C^N-ligands) of the appended aryl group in the solid state.

Electrochemical studies.

The representative voltammograms of complexes F and G are depicted in Figures S1 andS2, respectively, and the corresponding numerical data are summarized in Table S1 andS2 of n-Bu 4 NPF 6 as the supporting electrolyte at a scan rate of 100 mV s -1 and using ferrocene/ferrocenium (Fc/Fc + ) as the internal reference). The oxidation waves of F1-F4 are in the range of +1.08 to + 1.25 V vs. Fc/Fc + , which can be attributed to the Ir(III)/(IV) redox couple with contributions from the C^N ligands. 10a Upon the addition of aryl groups to the 5position of the phenyl ring, the oxidation waves of F2-F4 are slightly catholically shifted, reflecting the moderately increased electron density due to the presence of appended aryl substituents. The irreversible reduction waves are very comparable to one another. The HOMO-LUMO gaps, calculated from these potentials are comparable to that previously found for F1. 9 Both complexes F5 and F6 exhibit a quasi-reversible single-electron oxidation wave, a notably less positive oxidation potential than the 4,6-difluoro-based complexes, illustrating the electronic effect of the 3,5-fluorine substitution of the C^N ligands on the anodic potential. The G series of Ir(III) metal complexes, which are cationic, display less obvious oxidation peak, due to the reduction of electron density at the metal center compared to the F series of charge-neutral metal complexes. A feature which has been observed for bis-tridentate Ir(III) complexes, going from the charge-neutral to the cationic forms upon methylation. 16) - [a] the dihedral angle between the pendant aryl ring and fluorinated ring in C^N ligands. em λmax / nm [b]  / % [b, c] obs / μs [b] rad / μs [b] F1 [d] 266 (4.18) [a] UV-Vis spectra was recorded in CH2Cl2 at a conc. of 10 -5 M at RT. [b] PL spectra, lifetime and quantum yields were recorded in degassed CH2Cl2 at a conc. of 10 -5 M at RT. [c] Coumarin 153 (C153) in EtOH (Q.Y. = 58% and λmax = 530 nm) was employed as quantum yields standard. [d] our studies, for a better comparison.

Electronic absorption and emission properties. The photophysical properties of complexes

F1-F6 are summarized in Table 2, and their UV-vis. absorption and emission spectra are illustrated in Figure 3. The electronic absorption spectrum (CH 2 Cl 2 ) of F1 is comparable to that of the Firpic 5e, 9 displaying an intense intraligand (IL) band in the far UV (266 nm), and a moderately intense band at lower-energy (312 nm) due to π-π* transition of the C^N ligands.

The weak low-energy bands at 398 and 443 nm are typically attributed to metal-to-ligand charge transfer and ligand-to-ligand charge transfer (MLCT/LLCT) transitions. The introduction of the electron-withdrawing CF 3 group on the pyridyl ring leads to a modest bathochromic shift of the lowest-energy absorption, with respect to FIrpic. The profiles of the absorption bands of complexes F2-F4 are also similar to each other, showing a broad and red-shifted intense band in the UV region (260-360 nm), due to the additional aryl group.

The spectrum of F5, where the substitution pattern of the fluorine atoms is modified, is slightly perturbed, bathochromic shifted compared to that of F1. The arylated complex F6, shows a comparable behavior to F2-F4, the weaker band at wavelength longer than 400 nm has greater molar extinction coefficients, a feature also observed for the parent complex F5.

Upon photo-excitation at λ exc = 370 nm, CH 2 Cl 2 solutions of the F1-F4 complexes display intense luminescence into the blue-green region. Upon going from the unsubstituted FIrpic (λ em = 468, 495sh nm) 5e to the 5-CF 3 -substituted derivative F1, the room temperature emission spectrum in dichloromethane exhibits two emission peak maxima at λ = 492 nm and 516 nm, similar in shape but red-shifted by 24 nm. The emission band of F2 (λ em = 3 nm) and those of F3 and F4 (λ em = 7 nm) is negligible shifted when compared to the parent F1.

As the precursor complex, their emission arises from a mixture of 3 MLCT and 3 LC (ligand centered) transitions, with lifetimes found in the region of 1.4 μs. 5e This negligible impact observed upon arylation at the 5-position of the 4,6-difluorophenyl ring on emission arises from the almost orthogonal conformation of the appended aryl groups observed by X-ray studies and also reported in previous studies. 10e Notably, arylation leads to a significant enhancement of the luminescence quantum yields in dilute solution, PLQY of F2, F3, and F4 are increased up to unity. The substituted 3,5-difluorophenylpyridinato-based complex F6 displays an emission band peaking at 544 nm, red-shifted by 7 nm compared to that of the precursor 2-(3,5-difluorophenyl)-5-(trifluoromethyl)pyridine complex F5, both complexes emit in the green region with a similar quantum yield. The same bathochromic shift of 45 nm found for F5 relative to F1 and F3 with respect to F6 is attributed to the reduced impact of the electronic effect of 3,5-disubstituted fluorine atoms. The increase of luminescence lifetimes up to 4.55 µs for F6 suggests a more pronounced 3 LC character, the quantum yields being significantly unaffected despite the observed red-shift. The improvement of QY in solution-state upon introduction of an aryl substituent in F2-F4 is intriguing. One possible explanation for this feature could be an increase of the radiative rate constant due to a higher degree of rigidity of these congested molecules, compared to the unsubstituted complex F1.

The bulkiness would inhibit the attainment of a coplanar conformation and lowers the extension the π-conjugation of the system since the emission wavelength and lifetimes are relatively unaffected in F2-F4. It may be noted that for complex F6 having a different fluorine substitution pattern, the quantum yield does not significantly drop off despite the decrease of the emission energy, probably due to the counteracting effect of the aryl functionalization which would be expected to have a similar positive impact on  as found for F2-F4. Moreover, our results demonstrate that the ligand modification gives rise to the enhancement of the luminescence efficiency whatever the location of the added aryl group either onto the phenyl ring or the pyridine ring of C^N ligand for the aryl-substituted pyridine ligand of FIrpic. 10a em λmax / nm [b]  / % [b, c] obs / μ) [b] rad / μs [b] G1 263 (5.14) The second series of cationic complexes G dissolve in CH 2 Cl 2 to give yellow orange solutions at 298 K. The electronic absorption spectra of G1 exhibit an intense absorption band at 260-360 nm and a moderately intense band at 360-450 nm with a λ max at ca. 400 nm in dichloromethane (Figure 4). The complexes G2-G4 exhibit similar absorption spectra but with the observation of intense and very broad high-energy absorption bands from 270 nm to 380 nm due to the presence of the additional aromatic groups. As reported in the spectroscopic studies on related iridium(III) complexes, 10e the high-energy absorption bands transitions. Their electronic absorption data have been summarized in Table 3. The absorption tail (∼450-500 nm) is found to show insignificant changes in the absorption profiles, these weaker absorption bands are assigned to spin-forbidden ( 3 MLCT/ 3 LC) transitions. As depicted in Figure 4, upon photo-excitation at λ exc = 370 nm, all Ir(III) complexes show bright luminescence in fluid solution (CH 2 Cl 2 ) at 298 K. The profiles of the emission bands are found to be insensitive to the nature of the appended aryl groups of C^N ligands and to the location of fluorine atoms. The complexes G1-G4 show a small difference in emission peak wavelengths from 468 (497sh) to 478 nm (505sh). The emission ranges from blue to green, the red-shifted emission being observed for G5 (502 nm) and G6 (519 nm), a shift arising from the 3,5-fluorine substitution pattern, a feature also found for the related neutral complexes F5-F6. As expected, the different electronic effect of the fluorine in F5-6 has an impact on the nature of the emissive excited state which gives rise to longer lifetimes (see Table 3). By comparison, note that the related complex [Ir(Phppy) 2 (bpy)]PF 6 , (where Phppy is 2-([1,1'-biphenyl]-3-yl)pyridine), bearing a phenyl group trans to the Ir-C C^N bond exhibits a yellow-orange emission with a  PL of 13% in CH 2 Cl 2 . 12. Clearly, the combined effect of fluorine positioning in phenyl ring and a 5-CF 3 -substitution of dF-ppy leads to a noteworthy improvement of PLQY values with respect to the parent complex [Ir(ppy) 2 (bpy)]PF 6 (bpy = 2,2'-bipyridine). Moreover, our study shows an exceptionally high quantum yield values (unitary) for G3 and G4, the steric bulk and/or electronic effect provided by the incorporated aryl group does not affect the luminescence efficiency which are similar to the parent complex G1. However, the positive impact, clearly seen in the F series, cannot be evidenced in the present case. Although G2 displays an apparently erratic  value (83%), compared to G1 and G3-4, it exhibits a bright luminescence, the  value being in the same range than that of its congeners. In the other hand, a slight decrease of  is found for G6, with respect to G5, a trend already observed upon going from F5 to F6, which could be attributed to the decrease of emission energy.

CONCLUSION

Our catalytic approach namely regioselective Pd-catalyzed C-H bond arylations applied to 2- 146.7 (q, J = 4.1 Hz), 141.0 (t, J = 9.4 Hz), 134.2 (q, J = 3.5 Hz), 125.9 (q, J = 33.3 Hz), 123.5 (q,J = 272.3 Hz),119.8,110.1 (d,J = 26.7 Hz) ). 19 F{ 1 H} NMR (376 MHz, CDCl 3 ) δ (ppm) -62.4 (s), -112.9 (s).

13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 166. 1,160.3 (dd,J = 7.4,249.7 Hz),157.4,146.8 (q, J = 4.0 Hz), 139.6 (t, J = 9.8 Hz), 134.3 (q, J = 3.5 Hz), 133.2, 130.5, 130.3, 129.5, 125.9 (q, J = 33.2 Hz), 123.5 (q, J = 271.5 Hz), 119.8, 118.9 (t, J = 18.6 Hz), 110.5 (d, J = 27.9

Hz), 61. 3.44; found: C 62.12, H 3.23, N 3.56. 1) (142 mg, 0.55 mmol, 2.2 eq.) were suspended in a mixture of 2ethoxyethanol/water (5 mL, 3/1). The mixture was heated and kept at 125 °C under stirring.

Iridium(III) bis[2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridinato-N,C

After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in the next step without further purification. This complex and picolinic acid (104 mg, 0.75 mmol, 6 eq.) were dissolved in 2-ethoxyethanol (8 mL), and Na 2 CO 3 (159 mg, 1.5 mmol, 6 eq.) was added. The solution was heated at 125 ºC for 24 h. The solution was allowed to cool to room temperature. After concentration, the residue was purified by flash chromatography on silica gel (CH 2 Cl 2 -EtOAc, 75:25) to afford the desired complex F1 (135 mg, 65%). Hz), 121.9 (q, J = 270.4 Hz), 114.9 (dd, J = 2. The mixture was heated and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in the next step without further purification. This complex and picolinic acid (104 mg, 0.75 mmol, 6 eq.) were dissolved in 2-ethoxyethanol (8 mL), and Na 2 CO 3 (159 mg, 1.5 mmol, 6 eq.) was added. The solution was heated at 125 ºC for 24 h. The solution was allowed to cool to room temperature. After concentration, the residue was purified by flash chromatography on silica gel (CH 2 Cl 2 -EtOAc, 75:25) to afford the desired complex F2 (176 mg, 68%). 1 H NMR (400 MHz, Hz). 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 172.0, 168.9 (d, J = 6.9 Hz), 167.7, 167.6 (d, J = 7.2 Hz), 160.9 (dd, J = 7.0, 261.6 Hz), 160.5 (dd, J = 6.8, 260.9 Hz), 158. 6 (dd,J = 7.6,263.5 Hz),158.5 (dd,J = 7.4,262.7 Hz),153.3 (d,J = 7.6 Hz),152.5 (d,J = 7.7 Hz),151.3,148.4,145.8 (q,J = 4.3 Hz),144.7 (q,J = 4.5 Hz),139.6,136.1,134.3 (d,J = 22.9 Hz),132.3,132.0 (d,J = 7.3 Hz),131.0 (d,J = 4.6 Hz),130.9,129.2 (d,J = 11.7 Hz),128.8,, 126.1 (q, J = 35.6 Hz), 125.7 (q, J = 36.0 Hz), 123.4 (d, J = 22.9 Hz), 122.9 (d, J = 21.3 Hz), 121.9 (q, J = 271.4 Hz), 121.8 (q, J = 271.

Iridium(III) bis[2-(4'-cyano-2,6-difluoro-[1,1'-biphenyl]-3-yl

Iridium(III) bis[2-((4'-(ethoxycarbonyl)-2,6-difluoro-[1,1'-biphenyl]

3-yl)-5-(trifluoromethyl)pyridinato-N,C 2' ]picolinate (F3): IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0 eq.)

and ethyl 2',6'-difluoro-3'-(5-(trifluoromethyl)pyridin-2-yl)-[1,1'-biphenyl]-4-carboxylate (3)
(224 mg, 0.55 mmol, 2.2 eq.) were suspended in a mixture of 2-ethoxyethanol/water (5 mL, 3/1). The mixture was heated and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the dime r[Ir(C^N) 2 Cl] 2 , which was directly engaged in the next step without further purification. This complex and picolinic acid (104 mg, 0.75 mmol, 6 eq.) were dissolved in 2-ethoxyethanol (8 mL), and Na 2 CO 3 (159 mg, 1.5 mmol, 6 eq.) was added. The solution was heated at 125 ºC for 24 h. The solution was allowed to cool to room temperature. After concentration, the residue was purified by flash chromatography on silica gel (CH 2 Cl 2 -EtOAc, 75:25) to afford the desired complex F3 (175 mg, 62%). 6,161.0 (dd,J = 7.4,258.5 Hz),160.5 (dd,J = 7.4,257.9 Hz),158.9 (dd,J = 7.4,261.8 Hz),158.5 (dd,J = 7.4,261.9 Hz), 154.5 (d,J = 7.6 Hz),152.7 (d,J = 7.8 Hz),151.4,149.4,145.5 (q,J = 4.5 Hz),145.2 (q,J = 4.1 Hz),139.8,136.7,134.4,130.5,130.5 (m),130.0,129.4,129.1 (m),128.3,127.7 (m),125.3 (d,J = 16.7 Hz),124.9 (d,J = 16.2 Hz),121.2 (d,J = 23.9 Hz),115.7 (d,J = 19.3 Hz),114.8 (d,J = 18.7 Hz),60.7,13.7 4,148.4,145.8 (q,J = 4.6 Hz),144.7 (q,J = 4.9 Hz),139.4,136.4 (d,J = 10.8 Hz),135.9,134.3 (d,J = 25.8 Hz),130.5,129.1 (d,J = 10.9 Hz),128.2 (d,J = 7.2 Hz),127.4 (m), 125.9 (q, J = 36.7 Hz), 125.5 (d,J = 35.8 Hz),123.3 (d,J = 3.9 Hz),122.8 (d,J = 21.3 Hz), 122.0 (q, J = 272.1 Hz), 121.9 (q, J = 272.1 Hz), 115.5 (d,J = 18.9 Hz) [START_REF] Yu | Effect of Substituents on Properties of Diphenylphosphoryl-Substituted bis-Cyclometalated Ir(III) Complexes with a Picolinic Acid as Ancillary Ligand[END_REF]171.4 (d,J = 4.3 Hz),170.9 (d,J = 3.0 Hz),169.1 (dd,J = 11.2,238.3 Hz),168.8 (dd,J = 11.2,245.1 Hz),159.9 (dd,J = 12.5,238.7 Hz),159.7 (dd,J = 12.1,238.5 Hz),151.6,149.2,139.7,129.5,128.4,125.1 (d,J = 8.9 Hz),124.8 (d,J = 9.1 Hz), 127.9, 124.1 (q, J = 272.1 Hz), 122.5 (q, J = 271.8 =Hz), 122. 4, 122.1, 120.6, 120.3, 109 155.6, 155.5, 153.3, 150,6, 146.5 (q, J = 4.7 Hz), 137.2 (q, J = 3.4 Hz), 129. 6, 127.1 -126.6 (m), 126.0, 125.4 (q, J = 34.6 Hz), 123.9 (d, J = 20.9 Hz), 122.2 (q, J = 271. 9 (dd,J = 6.8,259.6 Hz),158.8 (dd,J = 7.4,263.0 Hz),155.6,155.2 (d,J = 7.4 Hz),153.4,150.7,146.2 (q,J = 4.6 Hz),137.4 (m),134.2,132.2,131.3,129.7,127.6 (q,J = 5.5 Hz),126.0,125.7 (q,J = 34.6 Hz),124.3 (d,J = 22.1 Hz),122.12 (q,J = 271.8 Hz),118.2,115.0 (d,J = 17.8 Hz), 112.0 (m), 1.5 equiv.). The resulting solution was stirred at RT over 16 hours away from light. After concentration, the crude mixture was purified by silica column chromatography to afford the desired complex G5 (181 mg, 70%). 1 H NMR (400 MHz, Acetone-d 6 ) δ (ppm) 8.79 (s, 2H), 8.57 (d,J = 8.6 Hz,2H),8.37 (dd,J = 2.1,8.7 Hz,2H),8.14 (d,J = 5.7 Hz,2H),4H),7.65 (d,J = 5.6 Hz,2H),6.69 (td,J = 2.4,9.4 Hz,2H), 2.66 (s, 6H). 19 (dd, J = 11.2, 238.9 Hz), 160. 5 (dd,J = 12.3,240.1 Hz),155.9,153.4,150.3,146.7 (dd,J = 9.2,17.6 Hz), 146.4 (q, J = 4.9 Hz), 136.4 (q, J = 3.4 Hz), 129.9, 126.2, 125.6 (q, J = 34. 1,165.9,174.2 (dd,J = 7.0,246.7),157.6 (dd,J = 7.0,246.7),155.1,154.2,149.9,145.6 (d,J = 4.6 Hz),136.0 (q,J = 3.8 Hz),133.7,130.4,130.3,130.1 129.1,126.2,120.5,124.4 (d,J = 2.6 Hz), 124.0 (d, J = 3.5 Hz), 121.8 (q, J = 274.1 Hz), 120. 5,109.7 (dd,J = 3.7,24.0 Hz),61.1,21.4,14.1 Experimental details on cyclic voltammetry, X-ray; 1 H, 19 F and 13 C NMR spectra, (PDF)

Iridium(III) bis[2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridinato-N,C

Iridium(III) bis[2-(4'-cyano-2,6-difluoro-[1,1'-biphenyl]-3-yl

Corresponding Author *yunchi@cityu.edu.hk, *veronique.guerchais@univ-rennes1.fr; *henri.doucet@univ-rennes1.fr; *jean-francois.soule@univ-rennes1.fr

  Arylation for the Preparation of Bright Emitting Iridium(III) Complexes Rabab Boyaala, Marie Peng, Wun-Shan Tai, Rachid Touzani, Thierry Roisnel, Vincent Dorcet, Yun Chi, Véronique Guerchais, Henri Doucet, Jean-François Soulé To cite this version: Rabab Boyaala, Marie Peng, Wun-Shan Tai, Rachid Touzani, Thierry Roisnel, et al.. Exploiting the Reactivity of Fluorinated 2-Arylpyridines in Pd-Catalyzed C-H Bond Arylation for the Preparation of Bright Emitting Iridium(III) Complexes. Inorganic Chemistry, 2020, 59 (19), pp.13898-13911. 10.1021/acs.inorgchem.0c01528. hal-03040129

Figure 1 .

 1 Figure 1. Selected Examples of Cyclometalated Iridium Complexes with difluorinated 2arylpyridine as C^N Ligand and Structure of the Investigated Charge-Neutral and Cationic Iridium Complexes

  ) containing new aromatically substituted C^N ligands based on 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine (1) and 2-(3,5-difluorophenyl)-5-(trifluoromethyl)pyridine (5) (Scheme 1), by using regioselective Pd-catalyzed C-H bond arylations. Various aryl groups substituted at the para-position by an electron-withdrawing group (CN, CO 2 Et, C(O)Me) are readily incorporated, the regioselectivity being electronically controlled by the two fluorine atoms of pro-ligands 1 and

3 and 4 Scheme 1 .

 341 Scheme 1. Pd-Catalyzed C-H Bond Arylation of 2-(2,4-Difluorophenyl)-5-(trifluoromethyl)pyridine (1) and 2-(3,5-Difluorophenyl)-5-(trifluoromethyl)pyridine(5)

Figure 2 .

 2 Figure 2. . Solid State Structures of Complexes F2, F5, F6, G3 and G5. Hydrogen atoms, solvent and counter anion are omitted for clarity. Thermal ellipsoids are at the 50% probability level.

  (see SI). Complexes F show irreversible (complexes F1, F3 and F4) or quasi-irreversible (complexes F2, F5 and F6) oxidation waves in their cyclic voltammograms in CH 2 Cl 2 (0.1 M

Figure 3 .

 3 Figure 3. Absorption and emission spectra (recorded in CH 2 Cl 2 at 298 K, λ exc = 370 nm) of the studied charge-neutral Iridium(III) complexes F1-F6.

Figure 4 .

 4 Figure 4. Absorption and emission spectra (recorded in CH 2 Cl 2 at 298 K, λ exc = 370 nm) of the studied charge-neutral Iridium(III) complexes G1-G6

  are assigned as π →π* intraligand transitions of the C^N and N^N ligands, as well as lowerenergy absorption bands in the visible region are assigned as the admixture of intraligand [π→π*] transitions and metal-to-ligand charge transfer (MLCT) [dπ(Pt)→π*(dmbpy)]

( 2 ,

 2 photon-counting system. Both wavelength-dependent excitation and emission responses of the fluorimeter were calibrated. Spectral grade solvents (Merck) were used as received. To determine the photoluminescence quantum yield in solution, samples were degassed using at least three freeze-pump-thaw cycles. The solution quantum yields are calculated using the standard sample which has a known quantum yield. Cyclic voltammetry was conducted on a CHI621A Electrochemical Analyzer. Ag/Ag + (0.01 M AgNO 3 ) electrode was employed as reference electrode. The oxidation and reduction potentials were measured using a platinum working electrode with 0.1 M of NBu 4 PF 6 in CH 2 Cl 2 and a gold wire with 0.1 M of NBu 4 PF 6 in THF, respectively. The potentials were referenced externally to the ferrocenium/ferrocene (Fc + /Fc) couple.

  To a 15 mL oven dried Schlenk tube, 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine (1) (259 mg, 1.00 mmol), ethyl 4-bromobenzoate (343 mg, 1.5 mmol), PivOK (280 mg, 2 mmol), DMA (3 mL) and PdCl(C 3 H 5 )(dppb) (30 mg, 0.05 mmol, 5 mol%) were successively added. The reaction mixture was evacuated by vacuum-argon cycles (5 times) and stirred at 150 °C (oil bath temperature) for 48 hours. After cooling the reaction at room temperature and concentration, the crude mixture was purified by flash chromatography on silica gel (EtOAc-Heptane, 70:30) to afford the desired compound 3 (277 mg, 68%

  To a 15 mL oven dried Schlenk tube, 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine (1) (259 mg, 1.00 mmol), 4-bromoacetophenone (299 mg, 1.5 mmol), PivOK (280 mg, 2 mmol), DMA (3 mL) and PdCl(C 3 H 5 )(dppb) (30 mg, 0.05 mmol, 5 mol%) were successively added. The reaction mixture was evacuated by vacuum-argon cycles (5 times) and stirred at 150 °C (oil bath temperature) for 48 hours. After cooling the reaction at room temperature and concentration, the crude mixture was purified by flash chromatography on silica gel (EtOAc-Heptane, 70:30) to afford the desired compound 4 (230 mg, 61%

13 C{ 1

 131 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 197.6, 160.7 (dd, J = 6.7, 253.5 Hz), 157.7 (dd, J = 6.9, 254.0 Hz),155.8, 146.6 (q, J = 4.0 Hz), 136.9, 133.8 (q, J = 3.5 Hz), 133.7, 131.5 (dd, J = 4.4, 10.3 Hz), 130.7, 128.3, 125.3 (q, J = 33.2 Hz), 123.8 (d, J = 10.7 Hz), 123.5 (q, J = 271.8 Hz), 123.0 (dd, J = 4.0, 12.7 Hz), 118.0 (t, J = 19.6 Hz), 112.5 (dd, J = 3.8, 22.8 Hz), 26.7. Elemental analysis: calcd (%) for C 20 H 12 F 5 NO (277.31): C 63.67, H 3.21, N 3To a 15 mL oven dried Schlenk tube, 2-chloro-5-(trifluoromethyl)pyridine (1.81 g 10 mmol), (3,5-difluorophenyl)boronic acid (1.97 g, 12.5 mmol), K 2 CO 3 (2.76 g, 20 mmol), toluene (16 mL), MeOH (2 mL) water (2mL) and PdCl(C 3 H 5 )(dppb) (0.120 g, 0.2 mmol, 2 mol%) were successively added. The reaction mixture was evacuated by vacuum-argon cycles (5 times) and stirred at 110 °C (oil bath temperature) for 16 hours. After cooling the reaction at room temperature and concentration, the crude mixture was purified by flash chromatography on silica gel 80:20) to afford the desired compound 5(2.07 g, 80%).1 H NMR (400 MHz, CDCl 3 ) δ (ppm) 8.96 (s, 1 ), 8.03(d, J = 8.3 Hz, 1H), 7.81 (d, J = 8.3 Hz, 1H), 7.60 (d, J = 7.2 Hz, 2H), 6.93 (t, J = 8.7 Hz, 1H).19 F{ 1 H} NMR (376 MHz, CDCl 3 ) δ (ppm) -62.5 (S), -108.8 (S).13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 163.4 (dd, J = 12.7, 248.6 Hz), 157.7,

  To a 15 mL oven dried Schlenk tube, 2-(3,5-difluorophenyl)-5-(trifluoromethyl)pyridine (5) (259 mg, 1.00 mmol), ethyl 4-bromobenzoate (343 mg, 1.5 mmol), PivOK (280 mg, 2 mmol), DMA (3 mL) and PdCl(C 3 H 5 )(dppb) (30 mg, 0.05 mmol, 5 mol%) were successively added. The reaction mixture was evacuated by vacuum-argon cycles (5 times) and stirred at 150 °C (oil bath temperature) for 48 hours. After cooling the reaction at room temperature and concentration, the crude mixture was purified by flash chromatography on silica gel (EtOAc-Heptane, 70:30) to afford the desired compound 6 (293 mg, 72%). 1 H NMR (400 MHz, CDCl 3 ) δ (ppm) 8.97 (s, 1 ), 8.16 (d, J = 8.0 Hz, 2H), 8.03 (d, J = 8.4 Hz, 1H), 7.85 (d, J = 8.3 Hz, 1H), 7.75 (d, J = 8.4 Hz, 2H), 7.61 (d, J = 8.0 Hz, 2H), 4.43 (q, J = 7.2 Hz, 2H), 1.43 (t, J = 7.1 Hz, 3H

  F{1 H} NMR (376 MHz, CDCl 3 ) δ (ppm) -62.1, J = 12.3 Hz), J = 11.7 Hz), J = 11.9 Hz), J = 11.6 Hz).13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 172.1, 169.1 (d, J = 7.0 Hz), 167.7 (d, J = 6.9 Hz), 164.5 (dd, J = 12.9, 260.0 Hz), 164.1 (dd, J = 12.6, 259.3 Hz), 162.4 (dd, J = 10.5, 261.9 Hz), 162.2 (dd, J = 10.2, 262.0 Hz), 153.5(d, J = 7.2 Hz), 152.4 (d, J = 7.3 Hz), 151.4, 148.3, 145.6 (q, J = 4.3 Hz), 144.5 (q, J = 4.8 Hz),139.2, 135.8 -135.5 (m), 129.0(d, J = 3.6 Hz),, 125.5 (q, J = 34.9 Hz), 125.1 (q, J = 34.7 Hz), 123.0(d, J = 21.1 Hz), 122.5 (d, J = 19.9 Hz), 122.1 (q, J = 271.4

  difluoro-3'-(5-(trifluoromethyl)pyridin-2-yl)-[1,1'-biphenyl]-4-carbonitrile (2) (198 mg, 0.55 mmol, 2.2 eq.) were suspended in a mixture of 2-ethoxyethanol/water (5 mL, 3/1).

  (d, J = 9.2 Hz, 1H).19 F{ 1 H} NMR (376 MHz, CDCl 3 ) δ (ppm) -62.1 (s), -62.8 (s), -107.6 (d, J = 11.1 Hz), -108.4 (d, J = 10.9 Hz), -112.5(d, J = 11.1 Hz), J = 11.1

  ), 1.40 (t, J = 7.1 Hz, 3H), 1.39 (t, J = 7.1 Hz, 3H).19 F{ 1 H} NMR (376 MHz, Acetone-d 6 ) δ (ppm) -63.2 (d, J = 154.6 Hz), -110.0 (d, J = 12.1 Hz), -110.6 (d, J = 11.9 Hz), -113.7 (d, J = 12.1 Hz), -114.1 (d, J = 12.0 Hz). 13 C{ 1 H} NMR (100 MHz, Acetone-d 6 ) δ (ppm) 172.0, 168.6 (d, J = 7.1 Hz), 168.0 (d, J = 7.2 Hz), 165.

  F{ 1 H} NMR (376 MHz, Acetone-d 6 ) δ (ppm) -63.0, -63.5, -102.2 (d, J = 5.8 Hz), -103.9 (d, J = 5.8 Hz), -120.6 (d, J = 6.0 Hz), -120.7 (d, J = 5.8 Hz). 13 C{ 1 H} NMR (100 MHz, Acetone-d 6 ) δ (ppm) 171.

  IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0 eq.) and 2',6'-difluoro-3'-(5- (trifluoromethyl)pyridin-2-yl)-[1,1'-biphenyl]-4-carbonitrile (2) (180 mg, 0.5 mmol, 2 eq.) were suspended in a mixture of 2-ethoxyethanol/water (5 mL, 3/1). The mixture was heated and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in the next step without further purification. The crude mixture of [Ir(C^N) 2 Cl] 2 (1.0 equiv.) was dissolved in 5 mL of CH 2 Cl 2 before addition of 4,4'dimethyl-2,2'-bipyridine (69 mg, 0.375 mmol, 1.5 equiv.) and AgPF 6 (95 mg, 0.375 mmol, 1.5 equiv.). The resulting solution was stirred at RT over 16 hours away from light. After concentration, the crude mixture was purified by silica column chromatography to afford the desired complex G2 (217 mg, 70%).1 H NMR (400 MHz, Acetone-d 6 ) δ (ppm) 8.81 (s, 2 ), 8.69 (dd, J = 2.6, 8.8 Hz, 2H), 8.46 (dd, J = 2.2, 8.8 Hz, 2H), 8.22 (d, J = 5.7 Hz, 2H), 8.07 (d, J = 2.1 Hz, 2H), 7.93 (d, J = 8.3 Hz, 4H), 7.75 (d, J = 7.9 Hz, 4H), 7.63 (d, J = 5.8 Hz, 2H), 6.21 (d, J = 9.4 Hz, 2H), 2.65 (s, 6H). 19 F{ 1 H} NMR (376 MHz, Acetone-d 6 ) δ (ppm) -63.5, -72.6 (d, J = 707.4 Hz), -109.1 (d, J = 11.7 Hz), -112.8 (d, J = 11.9 Hz). 13 C{ 1 H} NMR (100 MHz, Acetone-d 6 ) δ (ppm) 167.7 (d, J = 7.2 Hz), 160.

  F{ 1 H} NMR (376 MHz, Acetone-d 6 ) δ (ppm) -63.4, -72.2 (d, J = 708.3 Hz), -102.5 (d, J = 7.6 Hz), -118.8 (d, J = 7.8 Hz). 13 C{ 1 H} NMR (100 MHz, Acetone-d 6 ) δ (ppm) 170.7 (d, J = 4.6 Hz), 168.4

  IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0 eq.) and ethyl 3',5'-difluoro-3'-(5- (trifluoromethyl)pyridin-2-yl)-[1,1'-biphenyl]-4-carboxylate (6) (203 mg, 0.5 mmol, 2 eq.) were suspended in a mixture of 2-ethoxyethanol/water (5 mL, 3/1). The mixture was heated and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in the next step without further purification. The crude mixture of [Ir(C^N) 2 Cl] 2 (1.0 equiv.) was dissolved in 5 mL of CH 2 Cl 2 before addition of 4,4'dimethyl-2,2'-bipyridine (69 mg, 0.375 mmol, 1.5 equiv.) and AgPF 6 (95 mg, 0.375 mmol, 1.5 equiv.). The resulting solution was stirred at RT over 16 hours away from light. After concentration, the crude mixture was purified by silica column chromatography to afford the desired complex G6 (213 mg, 64%).1 H NMR (400 MHz, CD 2 Cl 2 ) δ (ppm) 8.47 (s, 2 ), 8.06(d, J = 8.2 Hz, 8H), 8.02 (d, J = 5.6 Hz, 2H), 4H), 7.46 (d, J = 7.2 Hz, 6H), 4.38 (q, J = 7.1 Hz, 4H), 2.71 (s, 6H), 1.41 (t, J = 7.1 Hz, 6H).19 F{ 1 H} NMR (376 MHz, CD 2 Cl 2 ) δ (ppm) -63.3, -73.0 (d, J = 710.9 Hz), -106.4, -120.9. 13 C{ 1 H} NMR (100 MHz, CD 2 Cl 2 ) δ (ppm) 170.

  19

Table 1 .

 1 Selected Bond Lengths (Å) and Angles (deg) for Complexes F1, F2, F5, F6, G3 and G5 with Estimated Standard Deviations (es's) Given in Parentheses.

					)			Bite angle (º)
			Ir-C	Ir-N	Ir-Npic	Ir-O	C C^N -Ir-N C^N	Npic-Ir-O	 [a]
	F1	9	1.988(4) 2.007(4)	2.039(3) 2.047(3)	2.154(3)	2.149(3)	80.38(16) 80.84(16)	76.65(13)	-
	F2	1.999(3) 2.006(3)	2.034(2) 2.054(2)	2.135(2)	2.140(18)	80.67(10) 80.88(10)	77.51(8)	64.30(4)/ 46.20(4)
	F5	2.009(3) 2.027(3)	2.048(2) 2.038(2)	2.128(2)	2.136(2)	79.57(10) 80.21(11)	77.70(8)	-
	F6	2.011(7) 2.033(7)	2.053(6) 2.051(6)	2.126(6)	2.138(6)	80.50(3) 80.60(3)	77.40(2)	68.20(12) 61.40(13)
			Ir-C	Ir-NC^N	Ir-NN^N	C-Ir-N C^N	NN^N-Ir-NN^N		[a]
	G3		2.014(5) 2.019(5)	2.043(4) 2.048(4)	2.138(4) 2.153(4)	80.50(2) 80.11(19)	76.54(17)	61.30(8) 53.00(9)
	G5		2.020(5) 2.023(5)	2.051(5) 2.055(4)	2.118(4) 2.131(4)	80.40(2) 79.90(2)	77.34(

Table 2 .

 2 Essential photophysical data of the studied bis-cyclometalated Ir(III) complexes F1-F6

	abs λmax / nm (ε /10	4 M -1 cm	-1 )	[a]

Table 3 .

 3 Essential photophysical data of the studied bis-cyclometalated cationic Ir(III)

	complexes G1-G6
	abs λmax / nm (ε /10	4 M -1 cm	-1 )	[a]

  , 105.2(t, J = 25.5 Hz). Elemental analysis: calcd (%) for C 12 H 6 F 5N (259.18): C 55.61, H 2.33, N 5.40; found: C 55.68, H 2.49, N 5.68.

  1 H NMR (400 MHz, CDCl 3 ) δ (ppm)9.02 (s, 1 ), 8.47 -8.36 (m, 3H), 8.12 -7.96 (m, 3H), 7.79 (d, J = 5.3 Hz, 1H), 7.54 (t, J = 6.6 Hz, 1H), 7.50 (s, 1H), 6.56 (t, J = 10.7 Hz, 1H), 6.46(t, J = 10.8 Hz, 1H), 5.82 (d, J = 8.3 Hz, 1H), 5.55 (d, J = 8.4 Hz, 1H).19

  7, 17.4 Hz), 114.6 (dd, J = 2.7, 17.7 Hz), 98.9(d, J = 27.3 Hz), 98.4 (d, J = 27.1 Hz). MALDI HRMS for C 30 H 15 N 3 F 10 193 Ir [M+H] + : found found 832.0062, calcd 832.066. Elemental analysis: calcd (%) for C 30 H 14 N 3 F 10 Ir (831.05): C 43.38, H 1.70, N 5.06; found: C 43.24, H 1.45, N 5.02

  The mixture was heated and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in the next step without further purification. This complex and picolinic acid (104 mg, 0.75 mmol, 6 eq.) were dissolved in 2-ethoxyethanol (8 mL), and Na 2 CO 3 (159 mg, 1.5 mmol, 6 eq.) was added. The solution was heated at 125 ºC for 24 h. The solution was allowed to cool to room temperature. After concentration, the residue was purified by flash chromatography on silica gel (CH 2 Cl 2 -

		. MALDI HRMS
	for C 48 H 31 N 3 O 6 F 10 193 Ir [M+H] + : found 1128.1677, calcd 1128.170. Elemental analysis: calcd
	(%) for C 48 H 30 N 3 O 6 F 10 Ir (1126.28): C 51.16, H 2.68, N 3.73; found: C 51.21, H 2.89, N 3.23.
	Iridium(III)	bis[2-(4'-acetyl-2,6-difluoro-[1,1'-biphenyl]-3-yl)-5-
	(trifluoromethyl)pyridinato-N,C 2' ]picolinate (F4): IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0 eq.)
	and 1-(2',6'-difluoro-3'-(5-(trifluoromethyl)pyridin-2-yl)-[1,1'-biphenyl]-4-yl)ethan-1-one (4)
	(153 mg, 0.55 mmol, 2.2 eq.) were suspended in a mixture of 2-ethoxyethanol/water (5 mL,
	3/1). EtOAc, 75:25) to afford the desired complex F4 (160 mg, 60%). 1 H NMR (400 MHz,
	CDCl 3 ) δ (ppm) 9.10 (s, 1 ), 8.55 -8.34 (m, 3H), 8.12 -7.94 (m, 7H), 7.94 (s, 1H), 7.65 -
	7.54 (m, 4H), 7.50 (d, J = 8.0 Hz, 2H), 6.06 (d, J = 9.2 Hz, 1H), 5.75 (d, J = 9.2 Hz, 1H),
	2.65 (s, 3H), 2.63 (s, 3H). 19 F{ 1 H} NMR (376 MHz, CDCl 3 ) δ (ppm) -62.2 (s), -62.8 (s), -
	107.2 (d, J = 11.4 Hz), -108.1 (d, J = 11.3 Hz), -112.2 (d, J = 11.7 Hz), -112.9 (d, J = 11.7
	Hz). 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 197.6, 197.5, 172.0, 169.1 (d, J = 7.0 Hz),
	167.8 (d, J = 6.7 Hz), 161.2 (dd, J = 7.1, 261.3 Hz), 160.8 (dd, J = 6.7, 260.6 Hz), 158.9 (dd,
	J = 10.0, 264.9 Hz), 158.8 (dd, J = 7.5, 262.6 Hz), 152.6 (d, J = 7.6 Hz), 151.7 (d, J = 7.4
	Hz), 151.

  , 115.1 (d, J = 19.1 Hz), 112.2 (t, J = 19.9 Hz), 111.7 (t, J = 19.7 Hz), 26.6. MALDI HRMS for C 46 H 27 N 3 O 4 F 10 193 Ir [M+H] + : found 1068.1466, calcd 1068.145. Elemental analysis: calcd (%) for C 46 H 26 N 3 O 4 F 10 Ir (1066.93): C 51.78, H 2.46, N 3.94 found: C 51.88, H 2.43, N 4.12.

	Iridium(III) bis[2-(3,5-difluorophenyl)-5-(trifluoromethyl)pyridinato-N,C 2' ]picolinate
	(F5): IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0 eq.) and 2-(3,5-difluorophenyl)-5-
	(trifluoromethyl)pyridine (5) (142 mg, 0.55 mmol, 2.2 eq.) were suspended in a mixture of 2-
	ethoxyethanol/water (5 mL, 3/1). The mixture was heated and kept at 125 °C under stirring.
	After 24 h, it was allowed to cool to room temperature and the solvent was removed under
	vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in
	the next step without further purification. This complex and picolinic acid (104 mg, 0.75
	mmol, 6 eq.) were dissolved in 2-ethoxyethanol (8 mL), and Na 2 CO 3 (159 mg, 1.5 mmol, 6
	eq.) was added. The solution was heated at 125 ºC for 24 h. The solution was allowed to cool
	to room temperature. After concentration, the residue was purified by flash chromatography
	on silica gel (CH 2 Cl 2 -EtOAc, 75:25) to afford the desired complex F5 (141 mg, 68%). 1 H
	NMR (400 MHz, Acetone-d 6 ) δ (ppm) 9.09 (s, 1 ), 8.49 (t, J = 7.8 Hz, 2H), 8.32 (d, J = 8.6
	Hz, 2H), 8.28 -8.19 (m, 2H), 8.00 (d, J = 5.3 Hz, 1H), 7.83 (dd, J = 2.5, 9.4 Hz, 1H), 7.79 -
	7.66 (m, 3H), 6.60 (td, J = 2.4, 9.3 Hz, 1H), 6.49 (td, J = 2.4, 9.5 Hz, 1H). 19

  The mixture was heated and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex, which was directly engaged in the next step without further purification. This complex and picolinic acid (104 mg, 0.75 mmol, 6 eq.) were dissolved in 2-ethoxyethanol (8 mL), and Na 2 CO 3 (159 mg, 1.5 mmol, 6 eq.) was added. The solution was heated at 125 ºC for 24 h. The solution was allowed to cool to room temperature. After concentration, the residue was purified by flash chromatography on silica gel (CH 2 Cl 2 -

	EtOAc, 75:25) to afford the desired complex F6 (186 mg, 66%). 1 H NMR (400 MHz,
	CDCl 3 ) δ (ppm) 9.11 (s, 1 ), 8.41 (d, J = 7.7 Hz, 1H), 8.10 -8.06 (m, 1H), 8.04 (d, J = 8.3
	Hz, 2H), 7.98 (d, J = 8.3 Hz, 3H), 7.95 -7.86 (m, 4H), 7.57 (t, J = 6.5 Hz, 1H), 7.51 -7.40
	(m, 5H), 7.33 (d, J = 8.0 Hz, 2H), 4.46 -4.31 (m, 4H), 1.39 (s, 6H). 19 F{ 1 H} NMR (376
	MHz, CDCl 3 ) δ (ppm) -62.2, -62.8, -107.3 (d, J = 7.0 Hz), -121.9 (d, J = 6.3 Hz), -122.3 (d, J
	= 6.9 Hz). 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ (ppm) 172.6, 170.1 (d, J = 4.3 Hz), 169.9 (d,
	J = 4.3 Hz), 166.2, 166.1, 165.5 (dd, J = 5.9, 240.5 Hz), 165.0 (dd, J = 5.9, 241.1 Hz), 157.1
	271.6 Hz), 122.0 (q, J = 271.6 Hz), 121.8, 121.4, 120.2 -119.9 (m), 119.8, 119.1, 108.8 (t, J
	= 23.7 Hz), 108.9 (t, J = 23.7 Hz), 61.1, 60.1, 14.3, 14.3. MALDI HRMS for
	C 48 H 31 N 3 O 6 F 10 193 Ir [M+H] + : found 1128.1677, calcd 1128.168. Elemental analysis: calcd (%)
	for C 48 H 30 N 3 O 6 F 10 Ir (1126.28): C 51.16, H 2.68, N 3.73; found: C 51.09, H 2.76, N 3.85.
		.1 (dd, J = 3.8, 22.2 Hz), 108.7 (dd, J = 3.8, 22.0 Hz),
	105.6 (dd, J = 24.9, 62.0 Hz), 105.6 (dd, J = 2.2, 24.8 Hz). MALDI HRMS for
	C 30 H 15 N 3 F 10 193 Ir [M+H] + : found 832.0062, calcd 832.066. Elemental analysis: calcd (%) for
	C 30 H 14 N 3 F 10 Ir (831.05): C 43.38, H 1.70, N 5.06; found: C 43.65, H 1.67, N 5.26
	Iridium(III)	bis[2-((4'-(ethoxycarbonyl)-3,5-difluoro-[1,1'-biphenyl]-4-yl)-5-

(trifluoromethyl)pyridinato-N,C 2' ]picolinate (F6): IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0 eq.) and ethyl

3',5'-difluoro-3'-(5-(trifluoromethyl)

pyridin-2-yl)-[1,1'-biphenyl]-4-carboxylate

(6)

(224 mg, 0.55 mmol, 2.2 eq.) were suspended in a mixture of 2-ethoxyethanol/water (5 mL, 3/1).

(dd, J = 6.6, 241.8 Hz), 156.7 (dd, J = 6.

5, 242.4 Hz), 151.5, 148.4, 129.3, 134.5, 134.0, 130.4 (d, J = 11.5 Hz), 130.0 (d, J = 30.7 Hz), 129.2, 129.1, 125.8 (d, J = 34.7 Hz), 125.4 (d, J = 34.4 Hz), 123.1, 133.8, 122.1 (q, J =

2' ]-4,4'-

  G1 (192 mg, 74%).1 H NMR (400 MHz, Acetone-d 6 ) δ (ppm)8.78 (s, 2 ), 8.63 (dd, J = 2.7, 8.8 Hz, 2H), 8.41 (d, J = 8.7 Hz, 2H), 8.11 (d, J = 5.6 Hz, 2H), 8.01 (s, 2H), 7.63 (d, J = 5.7 Hz, 2H),6.83 (ddd, J = 2.3, 9.3, 12.2 Hz, 2H), 5.97 (dd, J = 2.3, 8.5 Hz, 2H), 2.65 (s, 6H).19 F{ 1 H} NMR (376 MHz, Acetone-d6) δ (ppm) -63.4, J = 707.6 Hz), -

	104.8 (d, J = 11.9 Hz), -108.0 (d, J = 12.8 Hz). 13 C{ 1 H} NMR (100 MHz, Acetone-d 6 ) δ
	(ppm) 167.8 (d, J = 7.0 Hz), 164.6 (dd, J = 12.7, 258.5 Hz), 162.5 (dd, J = 13.2, 261.9 Hz),
	dimetyl-2,2'-bipyridine hexafluorophosphate (G1): IrCl 3 .6H 2 O (75 mg, 0.25 mmol, 1.0
	equiv.) and 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine (1) (129 mg, 0.5 mmol, 2 eq.)
	were suspended in a mixture of 2-ethoxyethanol/water (5 mL, 3/1). The mixture was heated
	and kept at 125 °C under stirring. After 24 h, it was allowed to cool to room temperature and
	the solvent was removed under vacuo to give the intermediate [Ir(C^N) 2 Cl] 2 dimer complex,
	which was directly engaged in the next step without further purification. The crude mixture
	of [Ir(C^N) 2 Cl] 2 (1.0 equiv.) was dissolved in 5 mL of CH 2 Cl 2 before addition of 4,4'-

dimethyl-2,2'-bipyridine (69 mg, 0.375 mmol, 1.5 equiv.) and AgPF 6 (95 mg, 0.375 mmol, 1.5 equiv.). The resulting solution was stirred at RT over 16 hours away from light. After concentration, the crude mixture was purified by silica column chromatography to afford the desired complex

3

  Hz), 124.7 (dd, J = 3.0, 36.4 Hz), 122.2 (q, J = 271.8 Hz), 121.1, 109.6 (dd, J = 3.8, 22.3 Hz), 106.5 (dd, J = 24.9, 32.3 Hz), 20.5. MALDI HRMS for C 36 H 22 N 4 F 10 193 Ir [M] + : found 893.1209, calcd 893.130. Elemental analysis: calcd (%) for C 36 H 22 N 4 F 16 PIr (1037.77): C 41.67, H 2.14, N 5.40; found: C 41.84, H 2.31, N 5.67.

  . MALDI HRMS for C 54 H 38 N 4 O 4 F 10 193 Ir [M] + : found 1189.2357, calcd 1189.239. Elemental analysis: calcd (%) for C 54 H 38 N 4 O 4 F 16 PIr (1334.09): C 48.62,H 2.87, N 4.20; found: C 48.45, H 2.90, N 4.21.

	ASSOCIATED CONTENT
	Crystallographic information file for F2 (CCDC 1964093) (CIF)
	Crystallographic information file for F5 (CCDC 1964103) (CIF)
	Crystallographic information file for F6 (CCDC 1964108) (CIF)
	Crystallographic information file for G3 (CCDC 1964137) (CIF)
	Crystallographic information file for G5 (CCDC 1964149) (CIF)

ACKNOWLEDGMENT

R.B. is grateful to "Université Mohamed Premier, Oujda, Morocco" for providing financial support. We thank CNRS (I.E.A. Hong Kong) and UR1 for providing financial support.