Kevin Levillain
email: kevin.levillain@mines-paristech.fr

Dana Brakman Reiser

Blanche Segrestin

Günter K Stahl

Christian Voegtlin

Christian Voegtlin The

The Purpose-Driven Corporate Forms: Tackling Grand Societal Challenges with Innovations in Governance and Corporate Responsibility

published or not. The documents may come

The Purpose-Driven Corporate Forms: Tackling Grand Societal Challenges with Innovations in Governance and Corporate Responsibility I.

SYMPOSIUM PRESENTATION AND PURPOSE

Faced with urgent social, environmental and economic issues, and notably a number of "grand challenges" raised by the objective of building a sustainable future for the planet [START_REF] George | Understanding and tackling societal grand challenges through management research[END_REF][START_REF] Reid | Earth System Science for Global Sustainability: Grand Challenges[END_REF], companies' capacity for action, and especially for innovation, is more and more expected to contribute to public good (Stahl & Sully de Luque, 2014), and appears to be essential in providing new solutions [START_REF] Voegtlin | Responsible innovation and the innovation of responsibility: Governing sustainable development in a globalized world[END_REF]. This, however, raises the issue of creating the appropriate conditions for businesses to combine innovation and social responsibility, notably through innovative "responsible governance" mechanisms to protect and foster responsible innovation [START_REF] Filatotchev | Corporate governance, responsible managerial behavior, and corporate social responsibility: Organizational efficiency versus organizational legitimacy?[END_REF][START_REF] Scherer | Corporate Governance for Responsible Innovation: Approaches to Corporate Governance and Their Implications for Sustainable Development[END_REF]. Amongst original ideas experimented by businesses and legislation, one has started to draw attention from both practitioners and researchers: the "profit-with-purpose" or "purpose-driven" corporate form [START_REF] Birkinshaw | Combining purpose with profits[END_REF][START_REF] Hiller | The Benefit Corporation and Corporate Social Responsibility[END_REF][START_REF] Prior | Profit-with-Purpose Businesses -Subject paper of the Mission Alignment Working Group: Social Impact Investment Taskforce[END_REF].

This new corporate model introduces an explicit social purpose into the articles of incorporation of typical for-profit structures [START_REF] Clark | How Benefit Corporations are redefining the purpose of business corporations[END_REF]. First introduced in some of the United

States in Benefit Corporation statutes starting in 2011 [START_REF] Reiser | Benefit Corporations-A Sustainable Form of Organization?[END_REF][START_REF] Reiser | Social Enterprise Law: Trust, Public Benefit and Capital Markets[END_REF], this corporate model has now spawned numerous variations in the United States, such as the Flexible or Social Purpose Corporation [START_REF] Reiser | Next Big Thing: Flexible Purpose Corporations[END_REF] and the Public Benefit Corporation in Delaware [START_REF] Alexander | Pursuing Profit With Purpose[END_REF][START_REF] Kurland | Accountability and the public benefit corporation[END_REF], as well as in Europe with the Società Benefit in Italy and the Entreprise à Mission currently under examination by the Senate in France. Other countries (e.g. United Kingdom, Brazil, Australia, etc.) are currently considering introducing similar corporate forms (see for instance the report on "mission-led businesses" for the UK government2 ).

The proponents of these new corporate forms highlight the strong potential these new forms might have to renew corporate governance practices at a time where they are increasingly questioned for their suspected negative societal impacts [START_REF] Clark | White Paper : The need and rationale for the benefit corporation: whi it is the legal form that best addreses the needs of social entrepreneurs, investors and ultimately the public[END_REF][START_REF] Mac Cormac | New Corporate Forms : One Viable Solution to Advancing Environmental Sustainability[END_REF]. By engaging the shareholders' commitment on social and environmental purposes, Profit-with-Purpose corporations intend to add credibility and protection to responsible and sustainable initiatives, reinforcing the strength of CSR practices against a risk of precariousness [START_REF] Fleming | The end of corporate social responsibility: Crisis and critique[END_REF]. Numerous actors have already bet on the potential of those new organizations to structure new activities: dedicated investment funds, purposeoriented consultancy firms, impact measurement methods, public support, etc.

However, this model's originality and novelty imply that its effects are still understudied to date. And the first papers published in the management field reveal nascent debates over the appropriate level of accountability that these forms will provide [START_REF] Ebrahim | The governance of social enterprises: Mission drift and accountability challenges in hybrid organizations[END_REF][START_REF] Kurland | Accountability and the public benefit corporation[END_REF] as well as their necessity to tackle the current limitations of CSR approaches [START_REF] Levillain | Protecting long-term commitment: legal and organizational means[END_REF][START_REF] Mcmullen | Should We Require Every New Venture to Be a Hybrid Organization[END_REF][START_REF] Rawhouser | Benefit Corporation Legislation and the Emergence of a Social Hybrid Category[END_REF]. How are they changing the generally accepted hypotheses underlying Corporate Governance theory? What new challenges are they likely to face and will these challenges affect the sustainability of this rapidly spreading model?

The aim of the symposium is to bring together panelists with contrasting theoretical and methodological approaches to pave the way for research assessing the true potential, as well as the theoretical and managerial implications of the adoption of such new corporate forms. We have invited a specialist in social enterprise law to discuss the challenges these companies face in selecting their legal forms and defining and maintaining their missions. Experts in corporate governance and strategy, will reflect on whether these new forms invent innovative governance practices, and discuss how managerial discretion and accountability (for instance on the additional purpose) can be affected positively or negatively, especially in relation to innovative strategies. Finally, experts in leadership and corporate social responsibility will investigate how the definition of a purpose might drive stakeholder engagement and enable to achieve the balance between their stakeholders' wishes.

We will also keep time for an interaction between the panelists and the audience through a moderated Q&A session of at least 20 minutes.

II. INTEREST TO THE IM, SIM AND STR SPONSOR DIVISIONS

The emergence of new corporate forms dedicated to social and environmental impacts draws a new bridge between the Corporate Governance and Corporate Social Responsibility fields.

Whereas CSR usually refers to practices that extend beyond the legal obligations pertaining to companies, Profit-with-Purpose corporations attempt to create a voluntary commitment, i.e. an optional statute within corporate law for interested entrepreneurs that is creating strong legal impacts. In that sense, it therefore opens new avenues beyond existing regulation practices [START_REF] Gond | The government of self-regulation: On the comparative dynamics of corporate social responsibility[END_REF], which revisit the institutional setting in which companies embed their socially responsible practices [START_REF] Aguilera | An organizational approach to comparative corporate governance: Costs, contingencies, and complementarities[END_REF], and create new means for policy makers to foster responsible innovation and steer political implications of CSR [START_REF] Scherer | Managing for Political Corporate Social Responsibility: New Challenges and Directions for PCSR 2.0[END_REF]. However, some practitioners contend that such forms might on the contrary offer a new opportunity for unethical firms to use the label for greenwashing purposes. These issues are at the heart of the works and theoretical frameworks sponsored by the SIM division.

The proponents of these new forms claim that the model might attract large companies such as Google or Danone, or new tech companies such as Kickstarter, which ground some of their #12409

image to the public on a societal mission. The impact of such new governance mechanisms is however still unclear both on the economic performance and on the societal impacts. The existence of new corporate forms also directly impacts the strategic choices made by entrepreneurs regarding appropriate governance structure, firm attractivity to customers and workers, as well as discourse and interaction with investors [START_REF] Gehman | Hidden badge of honor: how contextual distinctiveness affects category promotion among certified B corporations[END_REF]. The study of the consequences of these innovations in governance and their relationship with corporate leadership and accountability is in direct connection with the expertise of the STR division.

Finally, as the purpose-driven corporation movement is gaining momentum at the international level, especially through the sponsoring of some associations and the growing interest of numerous governments, it raises the issue of competing legal frameworks for companies operating in several countries, and requires advanced examination of the consequences of defining a purpose for instance at the holding level for the various subsidiaries established under different regimes, and operating in different cultural environments [START_REF] Matten | Implicit" and "Explicit" CSR: A Conceptual Framework for a Comparative Understanding of Corporate Social Responsibility[END_REF], which might be of interest for the International Management division.

III. PANELISTS

IV. FORMAT

The format of the 90-minute panel symposium will be as follows:

- Of the various legal forms U.S. state legislatures have designed to house purpose-driven forprofit firms in the past decade, the benefit corporation is most widely adopted. It is now available in at least 30 jurisdictions. The Delaware public benefit corporation (or PBC) is also highly significant, due to its provenance. The breadth and depth of these adoptions demonstrates the appeal of these forms as legislative products. State legislatures across the country, including the unchallenged leader in corporate law -Delaware -have jumped onto this bandwagon with breathtaking speed.

Yet these forms have proved less appealing to purpose-driven firms themselves. The most optimistic estimates still count the number of entities adopting them at a few thousand. Perhaps the benefit corporation and Delaware PBC forms simply need time to take off, but I believe the slow uptake reveals a more serious problem -one requiring significant redesign.

For the growing universe of purpose-driven firms to opt into benefit corporation or Delaware PBC form, doing so will need to brand them as genuinely purpose-driven and reliably prioritizing social good. These forms today establish no prioritization between profit and purpose; they simply say "do both." This lack of prioritization means a lack of guidance for those leading and investing in these organizations and, perhaps even more importantly, it makes enforcement impossible. Without clarity about their objectives, entrepreneurs and investors cannot rely upon and enforce the commitments of their counterparts. Indeed, benefit corporations and Delaware PBCs leave social mission vulnerable to unilateral termination by shareholders, who have unfettered discretion to discard social mission at any time, without penalty. These forms have achieved an important expressive victory, but they represent only a first step towards creating a legal regime that helps purpose-driven firms to flourish.

Christian Voegtlin (Audencia Business School)

The world is changing at an unprecedented speed, driven especially by technological innovation and the resulting behavioral changes in consumption, communication, mobility, and social life in general. These changes contribute to the grand challenges our planet is facing, like climate change, the economic disequilibrium between rich and poor, or mass migration, and in their wake, political and civil society movements emerge that propagate new forms of nationalism, fundamentalism and protectionism. These processes endanger the sustainable future for people and planet [START_REF] George | Understanding and tackling societal grand challenges through management research[END_REF]. In our presentation, we will outline our idea of responsible innovation and discuss the potentials and limitations of various models of corporate governance with regard to making responsible innovation feasible so that it contributes to sustainable development and helps addressing grand societal challenges. To this end, we will introduce alternative forms of participative and reflexive governance that can help address the social and environmental challenges that society faces. The presentation will thereby offer examples of innovative corporate governance aspects that can facilitate responsible innovation and link the discussion to the emerging purpose-driven corporate forms.

During our presentation, we will introduce responsible innovation as a normative concept that can be defined on the basis of three norms: avoiding harm, doing good, and coordinating with others to foster sustainable development [START_REF] Voegtlin | Responsible innovation and the innovation of responsibility: Governing sustainable development in a globalized world[END_REF]. We will further argue that corporate governance can help facilitating such an idea of responsible innovation. Finally, we will propose participative and reflexive structures as useful mechanisms for corporate governance that contributes to responsible innovation. We consider the emerging purpose-driven organizational forms ideal for integrating elements of reflexivity and deliberation.

However, being driven by a social purpose can create tensions for the business firm; limited resources must be deployed in pursuit of multiple objectives and bottom lines, thus raising questions about the prioritization of stakeholder demands. We will provide examples of corporate governance elements based on deliberation and reflexivity that should be conducive to dealing with these tensions [START_REF] Dryzek | Discursive democracy: Politics, policy, and political science[END_REF][START_REF] Dryzek | Deliberation as catalyst for reflexive environmental governance[END_REF].

Purpose-Driven Companies and the Pursuit of a Social Mission:

The Role of Executive Leadership

Günter K. Stahl (Vienna University of Economics and Business, WU Vienna)

The growing economic, social and environmental problems faced around the world are accompanied by increased pressure for corporations to "contribute to the creation of economic and societal progress in a globally responsible and sustainable way" (EFMD, 2005: 3). As the growing number of public-private partnerships, the emergence of dedicated CSR departments in many companies and corporate engagement in initiatives such the UN Global Compact demonstrate, many companies have committed to addressing these larger societal challenges.

Some have gone even further and adopted "profit-with-purpose" business models (Levillain, Segrestin & Filatotchev, 2017) with the explicit goal of aligning their activities with stakeholder needs to create "shared value" [START_REF] Porter | Creating Shared Value[END_REF] and contribute to the "triple bottom line" [START_REF] Elkington | Cannibals with forks. The triple bottom line of 21st century[END_REF][START_REF] Savitz | The triple bottom line: how today's best-run companies are achieving economic, social, and environmental success-and how you can too[END_REF] of social, environmental and economic responsibility.

We argue that executive leadership -particularly the CEO's approach to responsible leadership [START_REF] Maak | Business Statesman or Shareholder Advocate? CEO Responsible Leadership Styles and the MicroFoundations of Political CSR[END_REF] -plays a critical role in helping profit-with-purpose companies to pursue their broader social mission, incorporate responsibility and sustainability principles into their day-to-day operations, and build cultures that support the necessary transformation of business models, governance structures, and managerial mindsets [START_REF] Brown | Ethical leadership: A review and future directions[END_REF][START_REF] Pearce | Introduction to the special issue: The leadership imperative for sustainability and corporate social responsibility[END_REF][START_REF] Puffer | Ethical turnarounds and transformational leadership: A global imperative for corporate social responsibility[END_REF]. Ultimately, activities such as formulating corporate social responsibility (CSR) and sustainability strategies, aligning the business models and internal processes with stakeholder needs, and engaging in "responsible innovation" [START_REF] Voegtlin | Responsible innovation and the innovation of responsibility: Governing sustainable development in a globalized world[END_REF] are the result of top management (team) decisions, and so are activities that are widely considered irresponsible, such as fraudulent practices, employment discrimination, and harmful environmental policies. As Waldman (2011, p. 81) noted: "firms #12409

do not make decisions pertaining to responsibility or CSR; leaders do". It is striking, then, that -apart from anecdotal evidence -relatively little is known about the role of executive leadership in helping profit-with-purpose companies achieve their broader social missions.

In this presentation we will introduce a framework of responsible leadership that builds on the distinction between two kinds of responsible leader behaviors (see Crilly et al., 2008;Stahl & Sully de Luque, 2014;Wettstein, 2010): activities aimed at avoiding harmful consequences for stakeholders, such as avoiding employment discrimination, minimizing environmental pollution, enforcing safety standards, etc. (i.e., "avoiding harm"); and activities aimed at enhancing societal welfare, such as supporting community development, broadening access to products, designing employee-friendly workplaces, etc. (i.e., "doing good"). A company or manager may engage in responsible behavior (or refrain from irresponsible behavior) for a variety of reasons, e.g., to reduce legal and reputational risks (e.g., avoid practices that are potentially harmful to the environment); support the company's business model and strategy (e.g., invest in "green" technologies); or act in accordance with the company's mission and core values (e.g., Johnson & Johnson's famous credo, which challenges managers and employees to be "responsible to the communities in which we live and work and to the world community as well"). Thus, managers' motivations for engaging in economically, socially, and environmentally responsible behavior can roughly be classified into three broad categories: compliance-based; instrumental/strategic; and normative or values-driven. While these motivations are not mutually exclusive and all companies have to be compliant with the laws and regulations of the countries where they operate, decisions regarding CSR engagement often follow either an instrumental logic, stressing financial benefits and competitive advantages resulting from investments in CSR, with the ultimate goal of maximizing shareholder value; or a values-based and mission-led approach, with the ultimate goal of social wealth creation (e.g., Sully de [START_REF] De Luque | Unrequited profit: How stakeholder and economic values relate to subordinates' perceptions of leadership and firm performance[END_REF]Waldman & Siegel, 2008;[START_REF] Voegtlin | Responsible leadership in global business: A new approach to leadership and its multi-level outcomes[END_REF]. Some

#12409

leaders have managed to reconcile the tension between social objectives and economic imperatives by embracing an "integrative responsible leadership" philosophy (Maak, Pless & Voegtlin, 2016: 470) that involves building long-term relationships with diverse constituencies, with the objective of generating social, environmental, and economic value for all stakeholders.

An example is Frank Riboud, Chairman of Danone, who leads the firm as "a business that creates economic value by creating social value" [START_REF] Kruglianskas | Sustainability as innovation strategy: How sustainability and innovation drive each other and company competitiveness at danone[END_REF].

In our presentation we will contrast the different approaches to CSR (instrumental, normative, integrative) and explore the interplay of CSR approach/motivation and leadership. We propose that a predominantly instrumental approach to CSR will be associated with transactional leadership, whereas a predominantly values-based, purpose-driven approach will be associated with transformational leadership [START_REF] Groves | Examining leader-follower congruence of social responsibility values in transformational leadership[END_REF][START_REF] Zhu | The effect of authentic transformational leadership on follower and group ethics[END_REF] and the integrative approach will combine elements of both transformational and transactional leadership. We further propose that misalignment between a company's CSR approach and executive leadership will be associated with various negative outcomes, such as lower employee commitment and stakeholder engagement (the purpose-driven/ transactional leadership combination) or perceptions of leader hypocrisy and mistrust in management (the instrumental/ transformational leadership combination), as illustrated by Table 1. In the latter case, leaders who use the firm's broader social mission instrumentally by engaging in CSR when their "real" motivation is maximizing shareholder value face the inherent risk that stakeholders will detect their "moral fakery" (Quinn & Jones, 1995: 29) and sanction the company's "moral deceit". We will conclude with a discussion of the leadership challenges facing senior executives of "profit-with-purpose" companies, showing that the leaders of these companies face a fundamental challenge with regard to leadership -building commitment on the company's broader social mission among the shareholders (which will happen only if there is a perception on their part that management acts as a custodian of their interests, i.e., runs the #12409

business with the primary purpose to maximize shareholder value) and garnering trust from stakeholders by credibly communicating the non-intrumental nature of the firm's social mission (which tends to show in situations in which shareholder and stakeholder interests conflict).

Resolving this tension requires authenticity and a careful balancing of shareholder and stakeholder interests (i.e., an "integrative responsible leadership" philosophy). This legal innovation raises a theoretical question: why is it necessary to change corporate law?

While some stakeholder theorists have called for a "legal version of the stakeholder model" [START_REF] Donaldson | The stakeholder theory of the corporation: concepts, evidence and implications[END_REF], most scholars have so far considered that the CSR practices and stakeholder management were compatible with existing legal frameworks. While the dominant Agency theory framework is more and more criticized for being deceptive to the nature of corporate law [START_REF] Lan | Rethinking agency theory: the view from law[END_REF][START_REF] Bower | The error at the heart of corporate leadership[END_REF], several scholars contend that corporate law is indeed fundamentally more consistent with a stakeholder approach than a shareholder approach [START_REF] Driver | The Inconvenient Truth About Corporate Governance: Some Thoughts On Vice-Chancellor Strine's Essay[END_REF]. For instance, the Team Production theory, suggesting a director primacy model instead of a shareholder primacy, holds that directors are not agents of the shareholders but represent the corporation as a legal entity, and that the core principles of corporate law have thus been conceived precisely to avoid conflict between the various constituencies [START_REF] Lan | Rethinking agency theory: the view from law[END_REF]. In this view, corporate law enables the pursuit of joint welfare and a fair allocation of results among team members [START_REF] Blair | A Team Production Theory of Corporate Law?[END_REF].

How, then, can we interpret the widespread adoption of Profit-with-Purpose Corporations within these theoretical frameworks? Does this legal innovation not lead us to revise some of the premises of our views of the corporation?

In this presentation, we critically re-assess the compatibility of corporate law with stakeholder management. We aim at reviewing first the legal and managerial issues that justify the need for a new legal framework, and second the theoretical implications of such legal innovations. As they make explicit the purpose of collective action, beyond the mere rights of stakeholders, profit-with-purpose make visible in law the mandate and the role of management. We will thus discuss how profit-with-purpose corporations invite us to question our conceptualization of corporation and the way corporate law is viewed by corporate governance theories.

  WELCOME AND BRIEF INTRODUCTION TO THE SYMPOSIUM THEME, PURPOSE AND FORMAT (5-8 minutes) by Kevin Levillain -DISCUSSION BY PANELISTS (45 minutes) -Each panelist will develop their specific theoretical, methodological and/or practical point of view regarding the emergence of purpose-driven companies (10 minutes each). -Q&A SESSION AND DISCUSSION WITH AUDIENCE (30 minutes) -Kevin Levillain will moderate the discussion -DEBRIEFING & CONCLUDING STATEMENTS FROM THE PANELISTS (5-8 minutes) -

  Center for Management Science, MINES ParisTech, PSL Research University)With the Profit-with-Purpose Corporations (PPCs), different corporate laws have introduced an innovation to support the development of responsible business and stakeholder management.These new corporate forms blend a voluntary basis (only interested entrepreneurs choose one of the new legal forms) with judicial commitment (the chosen purpose is introduced into corporate bylaws with clear legal consequences).

  Hatchuel (2012) to propose a new innovation-based theory of the firm, which calls for a renewal of corporate law and of corporate governance principles (several awards, among which best book award in management from the French Academy of Management (2013)). She coordinates the interdisciplinary research program at the College des Bernardins on Government of the firm, creation of the commons and she chairs the European Academy of Management, since 2016, the topic "Rethinking the form, governance & legal constitution of corporations: theoretical issues & social stakes".

1. Dana Brakman Reiser, Professor of Law at Brooklyn Law School, is an expert on law and finance for social enterprises. Her most comprehensive work on the subject is Social Enterprise Law: Trust, Public Benefit, and Capital Markets (Oxford University Press 2017) (with Professor Steven A. Dean). Her scholarship also has appeared in Boston College Law Review, Emory Law Journal, Indiana Law Journal, and Notre Dame Law Review, among others. 2. Blanche Segrestin, Professor of Management at MINES ParisTech, PSL Research University holds the chair « Theory of the firm. Models of governance & collective creation » since 2015. Her research connects the theory of the firm with the collective development of innovation capabilities. She published a book Refonder l'entreprise with A. 3. Günter K. Stahl, Günter K. Stahl is Professor of International Management at WU Vienna. His current research interests include the drivers of corporate responsibility, leadership in times of turbulence and crisis, and the changing nature of global work. He has held responsible positions within various academic associations (including the IM Division of the Academy of Management), is a Senior Editor of the Journal of World Business, and Academic Fellow of the Centre for International Human Resource Management, Judge Business School, University of Cambridge, as well as Senior Fellow of the Centre for Global Workforce Strategy, Simon Fraser University. 4. Christian Voegtlin, is Associate Professor in Corporate Social Responsibility at Audencia Business School. His current research interests are in responsible innovation, responsible leadership and corporate social responsibility. His research has appeared in outlets such as Academy of Management Perspectives, Business Ethics Quarterly, Journal of Management Studies, and the Journal of Business Ethics. The research on responsible innovation is currently funded through a project by the Swiss National Science Foundation. 5. Kevin Levillain (facilitator), is Assistant Professor at MINES ParisTech, PSL Research University. His research focuses on the development of innovative corporate governance practices in relation to emerging corporate forms such as the "Profit-with-purpose" companies and their potential to sustain firms' innovation capabilities. He published the book "Les Entreprises à Mission" in 2017 (Ed. Vuibert, Paris), which received two awards as best book in management research in France (FNEGE and Consult'In France).

"Advisory panel to mission-led business review: final report" 2016, available at https://www.gov.uk/government/publications/advisory-panel-to-mission-led-business-review-final-report.

The content of the presentation is based on research developed together with Andreas Georg Scherer, University of Zurich


Amélie Wannebroucq

Rita Meunier-Prest

Jean-Claude Chambron

Claire-Hélène Brachais

Jean-Moïse Suisse

Marcel Bouvet

Synthesis and characterization of fluorophthalocyanines bearing four 2-(2thienyl)ethoxy moieties: From the optimization of the fluorine substitution to chemosensing

come

Synthesis and characterization of fluorophthalocyanines bearing four 2-(2-thienyl)ethoxy moieties: from the optimization of the fluorine substitution to chemosensing

Graphical Abstract

Tuning of the electron-donating/withdrawing balance in phthalocyanine complexes.

Introduction

The energy levels of highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) are responsible for the electronic and optical properties of molecular materials at the origin of their use in devices, such as organic light emitting diodes (OLED), organic field-effect transistors (OFET) or organic photovoltaic cells. Thus, it is of the utmost importance to be able to tune the energy of molecular orbitals. The nature of majority charge carriers in the channel of OFETs 1,2 and their charge transport properties 3,4 can be modified by the introduction of substituents. Tuning molecular orbitals energy is especially important in heterojunctions, in which the alignment of HOMO and LUMO determines the energy barrier at the interface between the materials, and by extension the current-voltage characteristics of the device. 5,6 More generally, the molecular orbitals energies affects the interfaces between molecular materials, and between molecular materials and electrodes. 7 Different substituents can be introduced to stabilize the orbitals, such as fluorine or carboxylate moieties, whereas alkoxy or amine groups shift up the energy levels of orbitals. In addition, the engineering of side chains allows for solution processing, [8][9][10] generally at room temperature, which is compatible with plastic substrates used in flexible electronics. 11,12 It is also require to develop printable and flexible sensors. 13 Research and innovation in the field of chemical sensors should deal at first with new sensing materials. Most of the sensing materials are metal oxides, which require high temperatures for operation (200 -400 °C) and even higher ones for their synthesis. On the contrary, molecular materials like polymers or macrocyclic compounds, such as porphyrin and phthalocyanine derivatives, can be deposited by solution processing, at room temperature. All the general aforementioned considerations on side chains engineering and on the tuning of orbital energy are especially relevant for these macrocyclic molecules. Thus, the introduction of alkyl or alkoxy chains on lanthanide phthalocyanines, such as the lutetium bisphthalocyanine LuPc2, and lanthanide porphyrins allowed for solution processing of OFETs 14 and chemical sensors. [15][16][17] Photophysical properties of phthalocyanines or phthalocyanine analogs also depend on the presence of electron-accepting or donating moieties. Previously, the introduction of fluorine atoms on the phthalocyanine ring led to n-type semiconductors useful to get n-type OFETs 18 and p-n heterojunctions, 19 which can be used as gas sensors. 20 A recent review on phthalocyanine-based OFETs shows the interests of phthalocyanine complexes in organic electronics. 21 Among other examples of chemical sensors, we can cite conductometric sensors based on thioalkyl-substituted LuPc2, deposited by a jet spray technique, to detect volatile organic compounds, 22 amphiphilic europium triple decker complexes deposited by quasi-Langmuir-Schaefer technique, for the detection of ozone, 16 or alkoxy lanthanide complexes deposited as Langmuir-Blodgett and Langmuir-Schaefer films used in voltammetric sensors. 23 In the present paper, we report on the synthesis of two new phthalocyanines bearing both electron-donating and electronwithdrawing substituents. While most molecular materials exhibit p-type conductivity, molecules bearing withdrawing substituents such as perfluorophthalocyanines can form n-type materials. However, it is of interest to have ambipolar materials, capable to exhibit both p-type and n-type conductivities, depending on the operating conditions. 24,25 This is the reason why we chose to introduce electrondonating substituents on a fluorinated phthalocyanine. In addition, we wanted to introduce some electrochemicallyactive moiety to open the door to other applications in electrochemistry. All these considerations led us to choose a thienyl-containing ethoxy group. This moiety was used by T. Nyokong on metallophthalocyanines, 26 for their electrocatalytic activity to determine L-cysteine concentrations in solution. The thienyl-containing ethoxy group was introduced by starting from 4-nitrophthalonitrile. The synthesis of fluorinated phthalocyanines bearing electrondonating moieties has been reported, but always by starting from a mixture of two phthalonitriles, one bearing the electron-donating substituent and the other being the tetrafluorophthalonitrile. [START_REF] Sharman | The Porphyrin Handbook[END_REF][START_REF] Kudrevich | [END_REF] Such a mixed condensation reaction leads to a mixture of molecules with five different chemical compositions, AnB4-n, with n = 0 to 4, if we call A and B the two substituted phthalonitrile molecules, the formula A2B2 corresponding to two regioisomers. 29 Herein we aim at introducing four electro-donating groups on a fluorinated phthalocyanine. Two possibilities are available. We could use the mixed condensation method, which starts from tetrafluorophthalonitrile (F4PN) and a phthalonitrile bearing the four electro-donating groups. Another approach would be to start from a monoalkoxy-trifluorophthalonitrile synthesized from F4PN. Using this method, the phthalocyanine formation is expected to lead to a mixture of four regioisomers of C4h , D2h , C2v and CS symmetry, close to the statistical ratio of 1:1:2:4, respectively, if their reactivity is identical to each other. [START_REF] Mckeown | The Porphyrin Handbook[END_REF] In this work, we will discuss at first the selective synthesis of these two precursors 1a and 4, and their full characterization by means of 19 F and 1 H NMR spectroscopies and thermal analysis, and, in the case of 1a, X-ray crystal structure analysis. The synthesis of the zinc phthalocyanine 5, obtained from 1a (Schemes 1 and 2), and of its analogue 6, obtained by reaction of 4 with F4PN (Scheme 3) will be reported next. Finally, the new phthalocyanines will be incorporated into a MSDI conductometric transducer, namely a Molecular Semiconductor -Doped Insulator heterojunction, together with the lutetium bisphthalocyanine LuPc2, and the first data on ammonia chemosensing will be presented. 16,[START_REF] Parra | [END_REF]32

Results and discussion

Syntheses

The 4-{2-(2-thienyl)ethoxy}-3,5,6-trifluorophthalo-nitrile (1a) was synthesized by reacting of 2-(2-thienyl)ethanol with tetrafluorophthalonitrile (F4PN) in the presence of sodium hydride NaH in dry tetrahydrofuran (THF). These conditions were chosen because the usual method, 33 that is to say the reaction of the alcohol in dimethylformamide (DMF), in the presence of potassium carbonate as a base, at 100 °C, over 24 h, was not efficient enough for the monosubstitution to occur. We only observed a partial conversion into 1a no matter the base we used, namely potassium carbonate 33 or even metallic sodium, 34 either at room temperature or at -10 °C. Having a selective reaction is crucial for this nucleophilic aromatic substitution since up to four substitutions can be formed. Using 19 F NMR spectrum analysis of the crude reaction mixture we determined the relative amount of the products obtained in the course of the synthesis of 1a run at room temperature to be as follows: unreacted F4PN (56%), 1a (26%), the by-products 1b (6%), 2a (4%), 2b (5%), 2d (1%), 3a (1%) and 3b (1%). It is noteworthy to mention that the by-product 2c is not visible on the spectrum, being masked by the signal of 1b (Fig. S1). The optimized conditions include the preparation of an alcoholate solution, with NaH as a base, at 0 °C and its very slow transfer by a cannula to a solution of F4PN cooled at -50 °C. In these conditions, the formation of the alcoholate is not quantitative and an excess of alcohol (1.3 eq.) and NaH (2 eq.) is necessary to get the target molecule in a very good yield, 93% after purification by chromatography. It is worth mentioning that raising the temperature and/or the rate of the addition of the alcoholate leads to a poorer selectivity despite the stoichiometry being the same. In such cases, the main byproduct is the phthalonitrile monosubstituted by the alkoxy chain in ortho position with regard to a cyano group (1b). Even with the excess of alcohol and NaH used in the optimized conditions, the disubstitution reaction was limited to 5%, and the corresponding products (2a-d, mainly 2a and 2b, Scheme 2) could be separated by chromatography. Also, after optimization, F4PN was fully converted, mainly into 1a (93%), with 2% of 1b and 5% of 2a-d, as identified by 19 F NMR of the crude reaction mixture.

The synthesis of 4 can be achieved by using classical conditions (K2CO3/DMF) for the nucleophilic substitution. 33,35 However, in the present study, traces of non-fully substituted intermediates complicated the isolation of the target compound. That was not the case when the conditions worked out for 1a (NaH/THF) were used. However, the experimental conditions are simpler than those of 1a, since the addition does not require the same level of control as for the selective monosubstitution, in particular regarding the addition rate. The yield after purification was 46%. Phthalocyanine 5 was obtained by heating 1a with zinc acetate in chloronaphthalene (Scheme 1), at 175 °C. This temperature was chosen after thermogravimetric analysis of 1a. After a few hours, the solution turned deep green. The mixture was held at this temperature for two more days. Compound 5 was precipitated by addition of cyclohexane and purified by washing with ethanol (yield = 77%). Compound 6 was obtained by reaction of 4 with F4PN in a molar ratio 1 to 3, with zinc acetate in chloronaphthalene, at 210°C (Scheme 3). The mixture was purified at first by silica gel column chromatography to separate the perfluorinated phthalocyanine (blue), then further purified on preparative silica gel plates. Compound 6 was obtained as a green product (yield = 0.6%). Both phthalocyanines were characterized by mass spectrometry.

NMR analyses

The syntheses carried out to optimize the reaction conditions Fig. 1 1 H (bottom) and 19 F NMR (top) spectra of 1a in CDCl3, with the integration values; the identification of all H and F atoms is given. allowed us to isolate the trifluorophthalonitrile monosusbtituted in ortho position with regard to a cyano group (1b), and also the di-and tri-substituted species, existing respectively as four (2a-d) and two (3a-b) regioisomers (Scheme 2). All compounds were characterized by 19 F NMR spectroscopy, the chemical shifts and coupling constants allowing for a complete attribution of the signals. 19 F NMR revealed to be a particularly powerful analytical method to identify the different isomers. The data are displayed in Table 1. JF-F couplings on a benzene ring are well known. 36 JF-F ortho is very near 20 Hz whereas JF-F varies in a broad range for meta (-20 Hz to +20 Hz) and for para (+ 5 Hz to +20 Hz) positions. However, in the case of methoxy-fluorophthalonitrile derivatives 34 coupling constants were found to be ca. 20, 14 and 9 Hz for JF-F ortho, meta and para, respectively. These coupling constants are very close to those we observed for 1a. Three doublets of doublets (dd) were observed for both monosubstituted molecules. In compound 1a, they appear at -120.1, -127.6 and -137.8 ppm (Fig. 1), and for compound 1b at -129.1, -136.7 and -143.1 ppm. For disubstituted molecules, among the four isomers, two are symmetrical, 2a and 2d, each showing one singlet. The unsymmetrical disubstituted isomers, 2b and 2c, are identified by two doublets with the same coupling constants that match with meta (2b, JF-F 12.3 Hz) and ortho (2c, JF-F 20.1 Hz) coupling. Finally, each trisubstituted derivative is identified by one singlet, at -122.6 and -133.5 ppm for 3a and 3b, respectively. For all these molecules, the chemical shifts appear between -120.1 and -129.1 ppm for fluorine atoms in ortho of cyano groups, and between -131.9 and 143.1 ppm for fluorine atoms in para positions. A more accurate way to attribute these chemical shift ranges is to identify the two nearest neighboring moieties. Thus, the signals of fluorine atoms between one cyano group and one alkoxy group lie between -120.1 and -122.8 ppm, those between two alkoxy groups are located between -131.9 and -133.5 ppm and those between one alkoxy group and another Table 1 Chemical shifts (ppm) of the fluorine atoms in molecules 1-3 as determined by 19 F NMR in CDCl3 fluorine atom between -136.7 and -143.1 ppm.

In the 1 H NMR spectrum of 1a, the ethylene bridge appears as two triplets. One of them is a triplet of triplets that results from a coupling (1.6 Hz) with the two fluorine atoms in ortho position of the alkoxy chain. This coupling is not visible in the 19 F NMR spectrum by a lack of resolution. For the thienyl group, the H in ortho of the sulfur atom appears as a doublet of doublets, the H in ortho of the chain as a multiplet and the third H as a pseudo doublet of doublets. The multiplet at 6.84 ppm, assigned to Hc, matches to only two protons, the signal of the two other Hc protons being coincident with the multiplet assigned to Hd, centered at 6.93 ppm (Fig. S2).

In the 19 F and 1 H NMR spectra of phthalocyanine 5 (Fig. 2 This corresponds to shifts of +0.39 and +0.36 ppm, respectively, compared to 1a. The third signal, at 4.53 ppm, can also be attributed to Ha, but of other isomers, with a shift of -0.15 ppm. Thus, from such a small negative shift of the signal of Hb, it is possible to deduce that a fourth signal lies in the water peak that would correspond to the 4 missing protons. All these phenomena observed in 1 H NMR spectrum result from the presence of several isomers, of the ring current effect and of a possible aggregation of the phthalocyanine 5.

Recording the 1 H NMR spectrum of 6 was not possible because of its high tendency to aggregate.

Mass and Infra-Red Analyses

High resolution mass spectrometry of compound 1a was carried out by electrospray, in positive ionization mode. It displays a parent ion at m/z = 309.0297 that corresponds to [M+H] + . The mass spectrum of 4 obtained by MALDI-ToF exhibits a signal at 671.0654, assigned to [M+K] + .

Compound 5 was also identified by electrospray mass spectrometry, in the same conditions, with a parent ion at m/z = 1297.0381 that corresponds to the monoprotonated phthalocyanine [M+H] + (Fig. S3). The mass spectrum of 6 obtained by MALDI-ToF exhibits also a signal at 1297.0806, assigned to [M+H] + (Fig. S4).

The IR spectrum of 1a shows additional C-H aromatic (3108 and 3086 cm -1 ) and aliphatic vibrations (2978 and 2964 cm -1 ) compared to the starting material. Moreover, the CN vibration peak, at 2239 cm -1 and 2232 cm -1 for 1a and 4, respectively, was shifted by -7 and -14 cm -1 compared to the starting material, in accordance with the replacement of withdrawing substituents by electrodonating moieties on the aromatic ring.

Cyclic voltammetry

The cyclic voltammogram (CV) of complex 5 was registered in DMF containing 0.1 M Bu4NPF6 at various scan rates (Fig. 3). Two reduction steps can be identified at -0.84 V (Epred1, irreversible system) and -1.05 V (reversible system, E°red2 = (Epcred2+Epared2)/2) vs SCE, which can be attributed to the successive reductions of the phthalocyanine ring, corresponding to the redox couples Pc 2-/Pc 3-and Pc 3-/Pc 4-, respectively. One oxidation peak attributed to the first oxidation of the phthalocyanine ring appears at +0.97 V (Epox1). These data were obtained using a freshly polished working electrode. After few CVs, an additional cathodic peak appears at ca. -0.4 V vs SCE.

Besides, when we started from a solution at a higher concentration (4x10 -3 mol L -1 ), this cathodic peak also appeared at -0.4 V (Epcagg), whereas a new anodic peak, at -0.56 V (Epaagg), increased cycle after cycle. This is due to the adsorption of aggregates at the surface of the working electrode.

Even though electrochemical potentials are determined for molecules in electrolytic solutions, they can be used to estimate the energy values of the HOMOs and LUMOs frontier orbitals. These are known to be responsible for the electronic properties of the corresponding materials, in the solid state. A consensus exists to calculate them from the onset potential, which is defined as the potential at which the initial electron transfer from the HOMO, or to the LUMO, arises on the cyclic voltammogram, by the increase of the anodic or cathodic current, respectively [37][38][39][40] The energies of the HOMO and LUMO of 5 are -5.37 and -3.462 eV, respectively, and -5.44 and -3.97 eV respectively for Zn(F16Pc). 41 This explains that the energy barrier observed in MSDI heterojunctions are lower when using 5 rather than the perfluorinated phthalocyanine as sublayer.

Electronic Absorption Spectroscopy

The electronic absorption spectrum of 5 in chloronaphthalene (Fig. 4) exhibits two main absorption bands in the UV-visible region: The Soret band at 363 nm (log  = 4.37) and the Q band at 695 nm (log  = 4.85), as expected for a phthalocyanine derivative. Two smaller bands associated to vibrations can be found at 625 nm (log  = 4.14) and as a shoulder at 666 nm. The Q band of 5 undergoes a bathochromic shift (10 nm) compared to the perfluorinated zinc phthalocyanine. 42 In this solvent, the Beer-Lambert law is valid, at least up to 10 -5 mol L - 1 . This is not the case in dimethylformamide (max = 687 nm) where aggregation occurs above 2x10 -6 mol L -1 . As a result there is an increase of the band at 651 nm, which is attributed to H aggregates. 43,[START_REF] Snow | The Porphyrin Handbook[END_REF] The phthalocyanine 6 exhibits the same kind of spectrum (Fig. S5) as 5. In chloronaphthalene the Q band can be found at 697 nm and the Soret band at 378 nm. The only difference is the value of the full width at half maximum of the Q band that is larger in 6 than in 5, namely 37 nm against 27 nm, at a concentration of 8x10 -6 mol L -1 . It indicates that for 6 aggregation already started at this concentration. In CH2Cl2 the Q band appears at 688 nm and the Soret band at 351 nm (Fig. S5), but the spectrum shows the presence of aggregates.

Thermal analysis 1a exhibits a fusion peak at 59 °C accompanied by a huge supercooling phenomenon. The DSC analysis shows that crystallization occurs at +22 °C during the cooling stage from the liquid phase, at 1 °C min -1 (Fig. S6). 4 exhibits a DSC thermogram with fusion (+23.2 °C) and crystallization (52.6 °C) temperatures rather close to those of 1a, with an important supercooling phenomenon as well. However, a major difference is that the crystallization phenomenon of 4 occurs during the heating stage, as shown in the second thermal cycle of Fig. S7. This means that the four thienylethoxy substituents prevent 4 from crystallizing easily.Both 1a and 4 have been analyzed also by TGA, at a heating rate of 5 °C min -1 , under nitrogen (Fig. S8). 1a shows only one weight loss step, higher than 99%, starting from 180 °C and finishing at 250 °C, whereas 4 exhibits a weight loss of ca. 50% between 260 °C and 320 °C. For the synthesis of phthalocyanines, due to the presence of fluorine atoms on the starting phthalonitrile, we cannot use the classical method that takes place in basic conditions in an alcohol as a solvent, usually nhexanol (boiling point 160 °C). High temperature conditions are needed. TGA allows us to know the highest reaction temperature compatible with the stability of the starting phthalonitrile. The TGA of 5 carried out at a heating rate of 2 °C min -1 showed two weight loss steps (Fig. S9). The first one (23%), from 200 to 330 °C, can be attributed to the loss of thienyl groups (calc. 26%), and the second one (68%), between 330 and 635 °C, can be attributed to the loss of all the macrocycle (calc. {-CH2CH2O}4F12Pc 69%). The residue (7%) mainly corresponds to the zinc atom (calc. 5%).

X-ray analysis of 1a

1a crystallizes in the monoclinic system (space group P21/c).

The thienyl substituent was found to be disordered over two positions (75%/25%) (Fig. 5). Within a molecule, the two rings make an angle of 59.45 intermolecular - interactions should also play a role in the packing of molecules in the solid state.

Electrical and sensing properties

Films of 5 and 6 were obtained by solvent cast, from 85 µL of DMF solutions, at concentrations of 3.3x10 -3 and 2.77x10 -3 mol L -1 , respectively, deposited dropwise on interdigitated electrodes (IDE). The substrates were heated at 60 °C in a closed desiccator in order to fully evaporate the solvent and increase the homogeneity of the films. Electrical measurements in ambient atmosphere showed that these films were too resistive to register I-V characteristics, at least up to +10 V, with the present IDEs. Only, an upper limit value for the conductivity can be guessed at. Their conductivity is lower than 5x10 -10  -1 .cm -1 , i.e. lower than for nonsubstituted phthalocyanine films in the same conditions. [START_REF] Bouvet | The Encyclopedia of Sensors[END_REF] However, it was possible to build MSDI heterojunctions, by vacuum evaporation of lutetium bisphthalocyanine, LuPc2, 50 nm in thickness, on films of 5 and 6. MSDIs are devices recently designed and patented by one of the authors. [START_REF] Parra | [END_REF][START_REF] Bouvet | [END_REF] The I-V characteristics obtained with the 5/LuPc2 and 6/LuPc2 MSDIs are symmetrical but not linear (Fig. S10 andS11), contrarily to what is observed for a LuPc2 resistor in the same potential range. [START_REF] Parra | [END_REF] The non-linearity is greater for the 6/LuPc2 MSDI, with a smaller current, ca. 0.6 A at 10 V, against 2.60 A at the same bias voltage for the 5/LuPc2 MSDI. This shows that the energy barrier between the molecular materials or the one between the sublayer and the electrodes is higher with 6 than with 5. This could be the result of a segregation between the fluorinated and nonfluorinated parts of the unsymmetrical phthalocyanine that would modify the interfaces with this sublayer. Under NH3, these MSDIs exhibit a current decrease (Fig. 6 and S12), as expected for a p-type MSDI heterojunction prepared from a p-type sublayer. [START_REF] Parra | [END_REF] This reveals that compounds 5 and 6 are capable of transporting majority charge carriers positive in nature, even though their density remains very low. This is not obvious when considering the presence of twelve fluorine atoms on the phthalocyanine ring.

It indicates that the four electron-donating alkoxy groups compensate, at least partly, the withdrawing effect of fluorine atoms. It is worth noting that, with a n-type sublayer, as found with perfluorinated phthalocyanines, NH3 induces a current increase resulting from the existence of energy barriers between the two molecular materials and between the electrodes and the sublayer. [START_REF] Bouvet | [END_REF] Measurements were carried out under controlled relative humidity (rh). At 30 % rh, the current reached 13 A under a polarization of 10 V for the 5/LuPc2 MSDI (Fig. 6). The response to NH3 depends on its concentration. For example, for the 5/LuPc2 MSDI, the response to 60 ppm NH3 was -0.5 A, which corresponds to a relative response, defined as (Ion-Ioff)/Ioff, of -3.8 %. This value is lower than the one obtained with a n-type MSDI device combining a perfluoro-phthalocyanine and LuPc2, about +25 % at 60 ppm, [START_REF] Bouvet | [END_REF] but very close to the one obtained with other p-type MSDIs, e.g. between -2 % and -4 % for Cu(tBu4Pc)/LuPc2 MSDIs prepared by different processes. 16 In the same conditions, in particular at a same relative humidity value, the 6/LuPc2 MSDI exhibits a response of -3.3 % at 60 ppm NH3 (Fig. S12), i.e. very close to the one of MSDIs prepared from 5. It is worth noting that the response to NH3 increases with the rh value, from -2.5 at 10 % rh up to 5.4 at 50 % rh.

Experimental Reagents and instrumentation

Chemicals. 2-Thienylethanol, sodium hydride (60% dispersion in mineral oil), MgSO4, Bu4NPF6, silica gel (technical grade, pore size 60 Å, 70-230 mesh, 63-220 µm), activated alumina (58 Å pore size) and chloronaphthalene (technical grade) were purchased from Sigma Aldrich and used as received. Tetrafluorophthalonitrile (F4PN) was purchased from Fluorochem Ltd and used as received. LuPc2 was synthesized according to a previously reported method. 48,49 Plates of silica gel 60 F254 (20x4 cm 2 ), 0.5 mm in thickness, with a concentrating zone, from Merck, were used for preparative liquid chromatography. Anhydrous zinc acetate was prepared from zinc nitrate and acetic anhydride and dried at 100 °C under primary vacuum. Tetrahydrofuran (THF, RPE) was distilled from Na and benzophenone, toluene (RE), dimethylformamide (DMF, RPE), CH2Cl2 (technical grade) and cyclohexane (RE, pure) were purchased from Carlo Erba. Absolute ethanol (analaR normapur) was purchased from VWR. Ammonia gas, 1000 ppm in synthetic air, was used from a standard cylinder, purchased from Air Liquide, France.

Characterization. Glass transition temperatures (Tg) and melting points (mp) were measured by differential scanning calorimetry (DSC Q1000 V9.9 Build 303). Experiments were performed under nitrogen, at a heating rate of 1 °C min -1 . Thermogravimetric analyses (TGA) were performed on a TA Instruments TGA Q500 thermoanalyzer using platinum pans, under flowing nitrogen gas. Weight loss percentages and onset temperatures were determined using the proprietary software TA Universal Analysis 2000. Elemental analyses were performed on an Analyzer CHNS/O Thermo Electron Flash EA 1112 Series. The UV-visible absorption spectra of solutions were obtained from a Varian UV-vis spectrophotometer Cary 50 using quartz cells and these of thin films were recorded using a Shimadzu UV-2600 Spectrometer with a bare floated glass substrate as a reference.

The infrared spectra were recorded on a Bruker Vector 22 using KBr pellets, in transmission mode. NMR spectra were recorded using a BRUKER 300 MHz Avance III Nanobay spectrometer. 1 H NMR spectra were calibrated with respect to TMS on the basis of the relative chemical shift of the residual non-deuterated solvent as an internal standard and 19 F NMR spectra were calibrated with respect to CFCl3. MS experiments were performed on a hybrid electrospray quadrupole time-of-flight mass spectrometer (Synapt G2 HDMS, Waters, Manchester, U.K.)) coupled to an automated chip-based nanoelectrospray device (Triversa Nanomate, Advion Biosciences, Ithaca, U.S.A.) operating in the positive ion mode. Denatured MS analysis was performed on the Synapt G2 HDMS instrument only, with external calibration using the multiply charged ions produced by 2 μM horse heart myoglobin solution diluted in water/acetonitrile/formic acid (50v/50v/1v), and classical interface tuning parameters of the mass spectrometer (Vc = 40 V, Pi = 2.1 mbar). MALDI-TOF mass spectra were obtained on a Bruker ProFLEX III spectrometer, using dithranol as a matrix. Single clear light colorless prism-shaped crystals of 1a were obtained by slow crystallization from a toluene solution. A suitable crystal (0.68 × 0.28 × 0.28 mm 3 ) was selected and mounted on a MITIGEN holder oil on a Bruker D8 VENTURE diffractometer. The crystal was kept at T = 100 K during data collection. Using Olex2, 50 the structure was solved with the ShelXT structure solution program, 51 using the Direct Methods solution method. The model was refined with version 2014/7 of ShelXL 52 using Least Squares minimization. All non-hydrogen atoms were refined anisotropically. Hydrogen atom positions were calculated geometrically and refined using the riding model. The thiophene substituant was found disordered over two positions (75%/25%) and some EADP constraints were employed to maintain a reasonable model.

Electrochemical

Measurements.

All electrochemical experiments were performed in DMF (dried by percolation on activated alumina) + Bu4NPF6 0.1 M, with a PGSTAT302 N (Metrohm) potentiostat connected to a PC and the data collected were analyzed using the Nova® 1.11 Software. Cyclic voltammetry (CV) was carried out by means of a threeelectrode configuration consisting of a Pt disk (1.6 mm in diameter, Bioanalytical Systems) as working electrode, a platinum wire as counter-electrode and an SCE electrode as reference separated from the solution by a glass chamber with a porous Vycor tip filled up with a saturated solution of Bu4NPF6 in DMF. Potentials were reported versus the saturated calomel electrode, SCE. The working Pt electrode was soaked for 10 min in KOH (2 M), polished with 0.1 µm alumina, etched for 10 min in concentrated sulfuric acid (2 M), sonicated first 10 min in water, then in absolute ethyl alcohol. The solutions were deoxygenated for 10 min with argon. A positive overpressure of argon was maintained above the electrolyte during the entire measurement performed at room temperature.

Device and electrical measurements. Electrical measurements were carried out with Indium Tin Oxide (ITO) interdigitated electrodes (IDE) separated by 75 m lithographied on a 1 x 1 cm² glass substrate. Thin films of phthalocyanines were prepared either by sublimation under secondary vacuum (ca. 10 -6 mbar) in a UNIVEX 250 thermal evaporator (Oerlikon, Germany), at a rate of 1 Å.s -1 , or by solvent cast technique from solutions in an organic solvent. Device and specific conditions were described previously. 53 Synthesis 4-{2-(2-Thienyl)ethoxy}-3,5,6-trifluorophthalonitrile (1a). A solution of 2-(2-thienyl)ethanol (1 mL, 9.75 mmol) and NaH (600 mg, 15 mmol) in THF (100 mL) was cooled at 0 °C under argon. The resulting 2-thienyl ethanolate solution was added dropwise by a cannula, in ca. 8h, in a solution of F4PN (1.5 g, 7.51 mmol) in THF (150 mL) at -50 °C. After complete addition, the reaction mixture was allowed to warm up to room temperature. Distilled water (10 mL) was added and the solution was concentrated under reduced pressure. After addition of water (100 mL) and CH2Cl2 (100 mL), the organic phase was separated and washed with water (3x100 mL), dried over MgSO4 and CH2Cl2 was evaporated off. The crude product was purified by chromatography on silica gel with toluene as eluent, to yield compound 1a as a colorless solid (2.14 g, 93%) after solvent evaporation. mp 55 °C, crystallization peak 22 °C (a 13.200 mg sample was heated from -20 °C to 70 °C, and cooled down to -20 °C, both at a rate of 1 °C min -1 ), dec. 200 °C (a 14.255 mg sample was heated from 30 °C to 650 °C at a rate of 5 °C min -1 (50 mL) was stirred at room temperature during 45 min under argon, then a solution of F4PN (0.747 g, 3.7 mmol) in THF (50 mL) was added under argon, by an addition flask. After 2 h, distilled water (2 mL) was added and the solution was concentrated under reduced pressure. After addition of water (100 mL), it was extracted with CHCl3 (100 mL). The organic phase was separated and washed with saturated water (3x100 mL), dried over MgSO4 and CHCl3 was evaporated off. The crude product was purified by chromatography on silica gel with CH2Cl2 / toluene (9:1) as eluent, to yield compound 4 as a colorless solid (1 g, 46 %) after solvent evaporation. mp 52.6 °C, crystallization peak 23.2 °C (a 10.700 mg sample was heated from -20 °C to 70 °C, and cooled down to -20 °C, both at a rate of 1 °C min -1 ), dec. 260 °C (a 8.029 mg sample was heated from 30 °C to 650 °C at a rate of 20 °C min -1 (5). 1a (315 mg, 1 mmol) and anhydrous zinc acetate (58 mg, 0.32 mmol) were stirred in 2 mL of chloronaphthalene. This mixture was heated at 175 °C under argon for 48 h. After cooling to room temperature, the crude product was precipitated with cyclohexane (8 mL), the supernatant was removed, and the procedure was repeated twice. The product was dried at 100 °C under reduced pressure for 2 h. The residue was washed with ethanol (2x20 mL), by stirring in an ultrasonic bath (30 min), and the product recovered by filtration through a millipore membrane (nylon, 10.0 µm, 25 mm). It was dried at 100 °C under reduced pressure for 2 h to yield a green solid (256 mg, 77% (6). F4PN (282 mg, 1.41 mmol), 4 (277 mg, 0.43 mmol) and anhydrous zinc acetate (255 mg, 1.38 mmol) were stirred in 2 mL of chloronaphthalene. This mixture was heated at 210 °C under argon for 48 h. After cooling to room temperature, the crude product was precipitated with cyclohexane (8 mL), the supernatant was removed, and the procedure was repeated twice. The crude product was purified by chromatography on silica gel with, successively THF / toluene (9:1) and ethyl acetate as eluents, allowing the elution of green and blue fractions, respectively. The green fraction was further purified on a preparative chromatography plate with CHCl3 as eluent. The product was dried at 100 °C under reduced pressure for 2 h to yield a green solid (3.6 mg, 0.6%). Elemental analysis: Found: C, 51.20; H, 2.42; N, 7.86. Calc for C56H28F12N8O4S4Zn: C, 51.8; H, 2.17

Conclusions

The reaction of tetrafluorophthalonitrile with 2-(2-thienyl)ethanol in the presence of a base allowed us to identify all the possible substituted derivatives, from mono-to tetraalkoxy phthalonitriles. The optimization of the reaction conditions and in particular the decrease of the reaction temperature and a very slow addition of the alcoholate solution, allowed us to obtain the monoalkoxy derivative 1a with a very good yield (93%). Its reaction with zinc acetate in chloronaphthalene, during two days, led to the formation of the tetraalkoxydodecafluorinated zinc phthalocyanine 5. The unsymmetrical analogue 6 was also synthesized by the mixed condensation of F4PN with the tetraalkoxyphthalonitrile 4. MSDI heterojunctions were prepared by coating these zinc phthalocyanines, used as poor conducting sublayers, with LuPc2 (50 nm) as a top layer. These MSDI devices exhibit symmetrical but nonlinear I-V characteristics, which brings to light the existence of an energy barrier at the interface between the materials. Chemosensing experiments under ammonia allowed us to demonstrate the positive nature of the majority charge carriers in 5 and 6. Work is currently in progress to modify the electron-donating/withdrawing balance in the phthalocyanine macrocycle in order to get an ambipolar material that is expected to exhibit original chemosensing properties.

  So, we need to synthesize the 4-{2-(2-thienyl)ethoxy}-3,5,6trifluorophthalo-nitrile (TF3PN, 1a) and the tetra-3,4,5,6-{2-(2thienyl)ethoxy}-phthalonitrile (T4PN, 4).

Scheme 1 Scheme 2 3

 123 Scheme 1 Synthesis of the phthalocyanine 5 (the isomer C4h is shown) and its precursor 1a

  The 1 H NMR spectrum of 4 exhibits 4 triplets in the region of the ethylene bridges (3-4.5 ppm), indicating that the four substituents are not equivalent: Those in ortho position relatively to the cyano groups are different from those in meta position. The spectrum is provided in the ESI (Fig.S2). The two triplets attributed to the CH2 connected to the O atoms appear at 4.15 and 4.26 ppm, i.e. at lower chemical shift compared to 1a, due to the absence of F atoms. This effect is smaller for the CH2 connected to the thienyl group, with two triplets at 3.08 and 3.28 ppm, vs. 3.36 in 1a. The signals assigned to the protons of thienyl moieties appear as three signals. The first one, centered at 7.16 ppm, assigned to He, appears as two pseudo triplets that actually result from the superimposition of two doublets of doublets slightly shifted from each other because of the lack of symmetry of the molecule. The coupling constants of He with Hd and Hc are 5.4 and 1.5 Hz, respectively.

  ), broad signals result from the existence of different isomers and from a possible aggregation in DMSO, despite the polarity of this solvent. The 19 F NMR spectrum shows mainly three signals, at -133.2, -142.5 and -146.3 ppm that can be attributed to F1, F4, and F3, respectively. They are shifted by ca. 13 and 15 ppm for the fluorine atoms in ortho position with regard to the macrocycle, compared to the chemical shifts in the starting phthalonitrile 1a, and by only 9 ppm for the F atom farther from the cycle, as a result of the ring current effect. The broadest signals are attributed to F atoms in ortho positions of the pyrrole subunit (F1 and F4) since they are more influenced by the effect of the neighboring groups. On the contrary, the third signal (F3) is sharper than the others because it lies farther from the neighboring cycles, no matter the symmetry of the phthalocyanine isomer. The presence of other smaller and thinner signals, near the main signals

Fig. 2 1

 2 Fig. 2 1 H (bottom) and 19 F (top) NMR spectra of 5 in DMSO-d6.attributed to F1 and F4, is due to the existence of different isomers of the phthalocyanine, as mentioned in the introduction when we start from nonsymmetrical phthalonitriles. The 1 H NMR shows one multiplet for the thienyl moieties, between 7 and 7.5 ppm that integrates for 12 protons, whereas for the CH2 groups three broad signals are visible, at 3.72, 4.53 and 5.04 ppm, which integrate for 12 protons. The signals at 3.72 and 5.04 ppm that have the same shape and height, can be attributed to Hb and Ha, respectively.

  They are calculated from the redox potentials determined in solution versus SCE as reference electrode: 𝑬 𝑯𝑶𝑴𝑶 = -(𝑬 𝒐𝒙𝟏/𝑺𝑪𝑬 + 𝟒. 𝟒) 𝑬 𝑳𝑼𝑴𝑶 = -(𝑬 𝒓𝒆𝒅𝟏/𝑺𝑪𝑬 + 𝟒. 𝟒)

Fig. 3

 3 Fig.3CV of 5, on Pt disc electrode, in DMF containing 0.1 M Bu4NPF6 , at a scan rate of 0.1 V s -1 , at a concentration of 10 -3 mol L -1 (solid blue line) and at 4x10 -3 mol L -1 (aggregation, dashed red line).

Fig. 4

 4 Fig.4UV-visible absorption spectra of 5 in chloronaphthalene (solid red line) and in dimethylformamide (dotted blue line), both at 8x10 -6 mol L -1 . The inset shows the variation of the absorbance at the maximum wavelength as a function of the concentration, in chloronaphthalene.

  (5) ° relatively to each other. The thienyl ring of one molecule is almost parallel to the benzene ring of a neighboring molecule, with an angle of 10.15(6) ° between their mean planes. The intermolecular distances between neighboring molecules are more interesting. The distance between the centroid of the benzene ring, defined from atoms C7 to C12, and the centroid of the thienyl ring is Ct-Ct = 3.8148(2) Å. The distance between the centroid of the benzene ring and the mean plane of the thienyl ring is 3.408 Å, and the one between the centroid of the thienyl ring, defined from S1 and C1 to C4, and the mean plane of the benzene ring is 2.795 Å. The shortest intermolecular distance can be found between one C atom of the thienyl ring and one C atom of the benzene ring, C(4)-C(8) = 3.275 Å. It is significantly shorter than the sum of van der Waals radii (3.40 Å). Thus, the crystal packing is controlled by some - interactions between the thienyl (D) and phthalonitrile (A) rings (Fig.5). The carboncarbon distances are 3.275 -3.758 Å between the aromatic rings. The projection on the (b, c) plane showing these - interactions makes clearly visible the existence of chains parallel to the c-axis. Crystallographically speaking, these molecules correspond to each other by a glide plane perpendicular to [0, 1, 0] with glide component [0, 0, ½]. Eventhough the withdrawing effect of cyano groups disappears in the case of the phthalocyanine molecule, - interactions could be preserved between thienyl rings and the electron poor benzene rings due to the presence of the fluorine atoms. Even though we have not structural information on the thin films of phthalocyanines, these

Fig. 5 X

 5 Fig. 5 X-Ray crystal structure of 1a: ORTEP representation (30% probability level) (top) and projection on the (b,c) plane (bottom). The shortest intermolecular distances are indicated (in Å).

Fig. 6

 6 Fig. 6 Response of a 5/LuPc2 MSDI heterojunction to ammonia (NH3, 90, 60 and 30 ppm), at 30% relative humidity, during exposure/recovery cycles (1 min/4 min).

  1437 and 1380] (C-F), 1306, 1145 (C-O), 995, 700 (C=C). 1 H NMR (300 MHz, DMSO-d6): (ppm) 7.20 (12H, m, Hc-e), 5.04 (4 H, s, Ha), 4.53 (4 H, s, Ha), 3.72 (4 H, s, Hb). 19 F NMR (282.4 MHz, DMSO-d6) :(ppm) -133.2 (F1), -142.5 (F4), -146.3 (F3). m/z (HR-ESMS) 1297.0381 [M+H] + , calculated 1297.0294.

  ; N, 8.63. max(CH2Cl2)/nm 690, 650 (sh), 619 (sh) and 350. FTIR (KBr pellet):  (cm -1 ) 3115 and 3073 (Ar-H), 2924 and 2854 (Aliph. C-H), 1636 and 1521 (C=C), [1487, 1455 and 1418] (C-F), 1369, 1349, 1333, 1313, 1270, 1146 and 1127 (C-O), 1011, 955, 693 (C=C). m/z (MALDI-ToF) 1297.0806 [M+H] + , calculated 1297.0289. The blue fraction was identified as Zn(F16Pc). m/z (MALDI-ToF), 863.7301 [M] + , calculated 863,9282. Crystal structure determination of 1a. C14H7F3N2OS, Mw = 308.28, colorless prismatic crystal (0.68 x 0.28 x 0.28 mm 3 ) monoclinic, P 2 1 /c (No. 14), a = 10.9995(8) Å, b = 12.9029(8) Å, c = 10.0701(7) Å, β = 111.081(2) • , α = γ = 90 • , V= 1333.55(16) Å 3 , T = 100 K, Z = 4, Z' = 1, (Mo K α ) = 0.71073 Å, μ (Mo K α ) = 0.277, 19925 reflections measured, 3059 unique (R int = 0.0482) which were used in all calculations. The final R2 was 0.1323 (all data) and R1 was 0.0532 (I > 2σ(I)).

9,16,23-tetra-{2-(2-thienyl)ethoxy}-1,3,4,8,10,11,15,17, 18,22,24,25-dodecafluorophthalocyanine

  JHa-Hb 6.9 Hz, Ha ortho and meta (CN)), 3.28 and 3.09 (2 x 4 H, 2 t, JHb-Ha 6.4 Hz, Hb ortho and para (CN)). m/z (MALDI-ToF): 671.0654 [M+K] + , calculated 671.0569.

	). Elemental analysis: Found: C, 60.95; H, 4.42; N,
	4.42. Calc for C32H28F3N2O4S4 C, 60.74; H, 4.46; N, 4.43. FTIR
	(KBr pellet):  (cm -1 ) [3103, 3085 and 3071 (Ar-H)], [2953,
	2915, 2891 and 2856 (Aliph. C-H)], 2232 (CN), 1560 (C=C),
	[1468, 1455, 1443 and 1433 (C-F)], 1115, [1042, 1027 and 1014
	(C-O)], 851, 832, 697. 1 H NMR (300 MHz, CDCl3): δ (ppm) 7.15
	(4 H, td, He), 6.93 (4 H, m, Hd), 6.83 (4 H, m, Hc), 4.28 and 4.15
	(2 x 4 H, 2 t, Zinc 2,

Acknowledgements

The authors acknowledge the Agence Nationale de la Recherche for funding through the ANR projects CAP-BTX 2010 and OUTSMART 2015 and the MENESR for a PhD grant (A. W.). Financial support from the European Union and the Conseil Régional de Bourgogne through the FABER and the PARI SMT 08 and CDEA programs is gratefully acknowledged. We would like to thank the European Union for fundings (FEDER and short term missions through the COST action TD1105 EuNetAir). Dr Yohann Rousselin (ICMUB) is thanked for the Xray structure determination of 1a, and Jean-Marc Strub (Univ. Strasbourg) for electrospray high resolution mass spectrometry analyses.