Maria Rita Manzini

Diego Pescarini

Negative Concord in North Italo-Romance: why neither Déprez nor Zeijlstra

Nobody sleeps'

Current analyses of NC provide no unified account of (1a) and (1b), which are therefore regarded as independent phenomena. Evidence from Northern Italian varieties, however, shows that there is a considerable amount of variation that cannot be adequately described by treating the two phenomena as separate. This provides both a descriptive and a theoretical challenge for existing theories.

 crucially compare the behavior of pas/pa under NC in Standard French and in French Creoles. The key parameter of Zeijlstra (2004, 2008, 2012) between Strict and Non-Strict NC is also illustrated by Romance languages (say Spanish/Italian vs. Romanian/French). Our first aim here is to show that North Italo-Romance data should not be neglected, since they in fact are problematic for both Déprez's and Zeijlstra's theories. 1 An anonymous reviewer points out that in colloquial French the preverbal negative marker ne can be omitted. Following Palasis 2013, we do not treat the omission of ne as an optional feature of French since ne is left out in certain registers, whereas it must always occur in Normed French, from which we exemplify.

 in addressing the cartographic analysis, reject the rigid adverbial hierarchies of the Cinque-Zanuttini analysis on the basis of additional and more detailed data (Manzini and Savoia 2011).

 Poletto (2012, 2018) refine the analysis of negative arguments and adverbs in a diachronic perspective introducing a distinction between negations restricted by a nominal content and pure functional negationsto which different positions are also associated in the sentential tree (argument position vs. edge position).

 provide data and discussion both for the parameter

Introduction

The debate on Negative Concord (NC) revolves around two mutual exclusion patterns: the incompatibility of preverbal negative-marked items and negation in non-strict NC languages such as Italian in (1a) and the incompatibility of adverbial negation and negative-items (nitems) in languages such as French in (1b).

(1) a. Nessuno (*non) dorme (It.) b. Personne ne dort (*pas) (Fr.) 1 concerning the possible combinations of sentential negation adverbs and negative arguments (Manzini and Savoia 2005, III: 258-285) and for the Strict/Non-Strict Concord parameter (Manzini and Savoia 2005, III: 313-320). [START_REF] Manzini | Grammatical Categories: Variation in Romance Languages[END_REF] explicitly propose that all visible n-morphology, including pas-type adverbial negators, are NPIs. They further envisage mutual exclusion between negative arguments and sentential negations as the result of locality constraint (specifically local anti-identity, akin to a morphosyntactic OCP). However their discussion does not contain an explicit comparison with mainstream theories, nor any mention of non-NC languages.

In short, it is fair to say that the literature on Italo-Romance in pursuing its own theoretical questions such as the proper categorization, internal structure and positioning of sentential negation has perhaps not paid as much attention to NC as the topic would have required. Nevertheless more recent literature has been quite explicit on the relevance of North Italian varieties to the NC debatesee notably [START_REF] Garzonio | Old Venetan and the typology of Negative Concord[END_REF]. The point we want to make here is that conversely, the literature on NC needs to take stock of a number of data of North Italo-Romance which in our view potentially undermine the various general approaches that have been proposed.

In this contribution, we first review the approach by Déprez and that of Zeijlstra in view of North Italian data. We conclude that both theories, as they now stand, present problematic aspects. We also briefly show that more recent alternatives to Zeijlstra's analyses within a general Agree-based view of NC fail to address the specific issues we pose, including approaches by [START_REF] Szabolcsi | Strict and non-strict negative concord in Hungarian: A unified analysis[END_REF], [START_REF] Garzonio | Old Venetan and the typology of Negative Concord[END_REF]. In the final section, we briefly reiterate the positions of NC already expressed by Manzini andSavoia (2011), Garzonio (2021).

2.

Déprez (2000,2011) vs. [START_REF] Zeijlstra | Sentential negation and Negative Concord[END_REF][START_REF] Zeijlstra | On the syntactic flexibility of formal features[END_REF][START_REF] Zeijlstra | There is only one way to Agree[END_REF] In this section, we outline the main tenets of both the Déprez and Zeijlstra analyses of NC. As we will see, from the point of view of the predicted variation, the two analyses are somewhat complementary: Déprez, studying French and French Creoles, mainly considers variation involving sentential negation adverbs (e.g. French pas). Vice versa, Zeijlstra crucially studies the Strict vs. Non-Strict NC parameterfocusing more on sentential negation clitics (or affixes).

Let us begin with the distinction between NC and non-NC languages. In non-NC languages two negative words within the sentential domain necessarily create a double logical negation reading, as in English (2a). In NC languages any combination of negative-marked words normally produces a single semantic negation reading, as in in Italian (2b). 2

(2) a. I didn't accomplish nothing. There are a limited number of ways to go about accounting for (2) and for the considerable number of parameters that characterize NC languages, concerning negativemarked words that can and cannot combine. One of these, associated especially with the work of [START_REF] Déprez | Parallel (a)symmetries and the internal structure of negative expression[END_REF][START_REF] Déprez | Atoms of negation: An outside-in micro-parametric approach to negative concord[END_REF], focusses on the nature of the negative-marked arguments, assuming that sentential negations (or at least sentential negation adverbs) are stable externalizations of the logical negation. The key NC languages for Déprez are French and Haitian Creole. As is well-known, French has a double sentential negation ne...pas, as in (3a) though ne can be 2 Since either nothing or anything are appropriate English translations for Italian niente and similar items in NC languages, we will adopt the convention of glossing niente as 'n-thing', nessuno as 'n-one' or 'n-body' and so on.

omitted in informal speech. Two negative items can easily combine as in (3d), however not even a single negative item can combine with pas, as in (3b-d).

(3) a. For [START_REF] Déprez | Parallel (a)symmetries and the internal structure of negative expression[END_REF][START_REF] Déprez | Atoms of negation: An outside-in micro-parametric approach to negative concord[END_REF], pa/pas is the logical negation operator in both French and in Haitian Creole while the negative-marked arguments in fact differ in the two languages, along the lines of (5) (Déprez 2011: 232) [START_REF] Zeijlstra | Sentential negation and Negative Concord[END_REF][START_REF] Zeijlstra | On the syntactic flexibility of formal features[END_REF]Zeijlstra ( , 2011)). The key parameter considered by Zeijlstra is that between Strict and Non-Strict NC languages. Following [START_REF] Zeijlstra | On the syntactic flexibility of formal features[END_REF] The account proposed by [START_REF] Zeijlstra | On the syntactic flexibility of formal features[END_REF] for the contrast in ( 6)-( 7) provides a good introduction to his general model and to some of the means he has at his disposal to account for variation. The basic idea of Zeijlstra is that NC is a purely syntactic phenomenon of agreement -and as such it is adequately modelled by [START_REF] Chomsky | Minimalist inquiries: The framework[END_REF][START_REF] Chomsky | Derivation by phase[END_REF]

[uNEG] [T' non[iNEG] ha [VP chiamato]]] b. [CP Op[iNEG] [TP nessuno[uNEG] [T' ha [VP chiamato]]]]
Strict NC languages like Czech are simply languages where the schema in (8b) is generalized. In Czech, the Neg clitic is [uNeg] exactly like all n-items, pointing to the presence of an abstract [iNeg] operator licensing all negative elements, along the lines of ( 9).

( As previously mentioned, the DN reading in (11) and, hence, the ungrammaticality of NC, receives a semantic explanation. The lack of NC between pas and other n-items does not follow from the agree mechanism, i.e. from the syntactic distribution of [iNEG] and [uNEG].

This is a rather unwelcome result for a theory that aims at a syntactic account of NC. French therefore provides us with a first glimpse into the issues that clitic…adverb discontinuous negations raise for the Agree theory of NCnamely, raising the need for more or less additional statements about observed variation.

Vice versa, the question arises how Déprez accounts for the Strict/Non-Strict NC facts.

In her terms [START_REF] Déprez | What is Strict Negative Concord?[END_REF]), Strict NC, as observed in Haitian Creole, is a result of the subject NPI reconstructing in the scope of the Neg operator (pa in Haitian Creole). Therefore, besides the parameter concerning the quantification or free variable status of NPIs/NCIs her system requires a second independent parameter concerning reconstruction.

On the other hand, no problem arises for elements like French ne "which acts as a doubling negative marker of the French NCI, but never has a negative import of its own, since it is unable to negate a simple declarative proposition", see for instance (12). Indeed, "the doubling negation marker has no semantic import and, consequently, is a mere morphological marker or an expletive negation that must be licensed essentially along the same lines as the NCI themselves" (Déprez 2017:104). But as we will see, in North Italian clitic…adverb negation systems, the negation is not necessarily inert as in French, raising doubts about the possibility of generalizing the simple treatment proposed for French. In other words, complex negation systems do not appear to be any easier to handle for Déperz than for Zejilstra.

(12) *Jean ne mange une pomme John NEG eats an apple 'John doesn't eat an apple'

Discontinuous negation and NC: new challenges

As is well-known from [START_REF] Zanuttini | Negation and Clausal Structure A Comparative Study of Romance Languages[END_REF] 6 Several varieties have a second sentential adverb often characterized as 'presuppositional' [START_REF] Zanuttini | Negation and Clausal Structure A Comparative Study of Romance Languages[END_REF])and that generally cooccurs with n-marked arguments. This is the case for Finale Emilia, where the relevant form is miŋga. In fact in a small subset of varieties where the (ordinary) sentential negation adverb cooccurs with other nitems (see section 4), the two adverbs (ordinary and presuppositional) can combine [START_REF] Manzini | I dialetti italiani e romanci[END_REF]. [START_REF] Dagnac | Concordance négative optionnelle: contrastes forts et faibles entre picard et québécois[END_REF] illustrate similar facts in Picard. Incidentally, the very limited extent to which North Italian data have entered the NC debate is attested by the fact that Tortora and Blanchette (2020), while commenting on the data of Picard, do not draw any parallel with North Italian. The whole matter is orthogonal to present concerns. Describing the language of Finale in ( 13)-( 15) in the terms of Déprez becomes very difficult.

On the one hand, exactly as in French ( 12) the clitic of Finale cannot negate by itself, see the examples in (13). Therefore it ought to be a mere morphological marker devoid of any role in the negation system of the language, as Déprez (2017) claims for French ne. Yet it is evident that in (15) the sentential negation clitic is mutually exclusive with the prenominal n-subjectthough it combines with any postnominal n-item, including the postverbal subject in (14d). This is the pattern that we expect from a Non-Strict NC language like Italian. But if so, the explanation presupposes that the clitic is the negation operator. This is in contradiction with the necessity for the adverb to be the logical operator, in order to predict its mutual exclusion with any n-item.

Perhaps more fundamentally, the data in ( 13)-( 15) are at odds with [START_REF] Déprez | Parallel (a)symmetries and the internal structure of negative expression[END_REF][START_REF] Déprez | Atoms of negation: An outside-in micro-parametric approach to negative concord[END_REF] hypothesis that NC (or the lack thereof) hinges on the distinction between NPIs and (strong) negative quantifiers. Recall that in her terms negative operators corresponding to sentential negations cooccur with NPIs (Haitian Creole), but are mutually exclusive with nitems bearing quantificational force, though the latter cooccur with one another due to quantifier absorption. North Italian clitic-adverb sentential negations point to the different conclusion that cooccurrence or mutual exclusion of sentential negations with n-items does not depend on the different semantics of the latter, but rather on the properties of the sentential negations themselves.

This then could lead us towards the analysis of [START_REF] Zeijlstra | Sentential negation and Negative Concord[END_REF] where NC parameters are imputed to the feature properties of sentential negations. In reality, it seems to us that Agree approaches are equally at pain to describe Finale-type languages even if one resort to a semantic explanation like Zeijlstra 2022 does for French. The non-strict NC pattern in (15) shows that neither the clitic nor the adverbial negator are ruled out because of semantic factors: if the former were a NPI (as Zeijlstra suggests for French), it would always co-occur with n-items, contra (15). Analogously, if the adverbial negator were semantically negative (as Zeijlstra suggests for French), it would never co-occur with the covert negative operator, contra (14).

Rather than trying to work out existing theories for this particular issue, in the next section we will present an independent case study which further undermines the accounts of both Déprez and Zeijlstra.

Simple verb vs. auxiliary-participle contexts

In section 3 we considered a variety where there is mutual exclusion between the sentential negation adverb and n-items. However, in other varieties sentential negation adverbs systematically cooccur with n-items. The evidence relevant for the present discussion has to do with a certain number of varieties where mutual exclusion of the sentential negation adverb and n-items is determined by the syntactic context. Specifically, mutual exclusion of the sentential negation adverb (n-adv) is found with simple inflected verbs only if the same restriction is observed in auxiliary-participle constructions (p < 0.00001), as shown in Table 2. Both the data and the analyses go back to Manzini andSavoia (2005, 2011), though here we make their relevance explicit for the Agree model of NC. hypothesis. Needless to say, we keep predicting mutual exclusion, contrary to fact. To be more precise, we may assume that auxiliary-participle sentence have a richer internal structure than simple verb structures. For instance, we may assume that auxiliaries really are lexical verbs selecting a reduced (participial) complementalong the lines of [START_REF] Kayne | Toward a modular theory of auxiliary selection[END_REF], Manzini andSavoia (2005, 2011). However even a participial structure endowed with some autonomous functional structure could not be associated with a C layer hosting a covert [iNeg] operator.8

Let us then try the opposite strategy. Looking at the data in (18), we may surmise that Cantoira is a language just like Fontane in ( 16) where the sentential negation adverb carries [uNeg]. But this hypothesis fares no better, since the impossibility of combining sentential negation and n-items in (17) remains unexplained. It is possible that there are other combinations of [uNeg] and [iNeg] that escape ushowever it seems to us that, as the theory now stands, data like ( 17)-( 18) inescapably give rise to some internal contradiction. The root of this contradiction is that in the asymmetric definition of Agree of [START_REF] Chomsky | Minimalist inquiries: The framework[END_REF][START_REF] Chomsky | Derivation by phase[END_REF], a

given element can only be a probe (uninterpretable) or a goal (interpretable). Suppose then we follow [START_REF] Zeijlstra | Sentential negation and Negative Concord[END_REF][START_REF] Zeijlstra | There is only one way to Agree[END_REF] in imputing NC to multiple Inverse Agree (several uninterpretable probes but a single interpretable goal). Any given element, say ɲiŋ in ( 17)-( 18), can either be a probe or a goalbut the theory of Agree is predicated on the idea that the two values cannot be switched around depending on the context of merger.

The problem is compounded by the observation that though the language of Cantoira clearly allows the systematic cooccurrence of the sentential negation adverb with VP-internal n-items, it blocks its cooccurrence with n-marked preverbal subjects even in compound tenses, as shown in (19b). By contrast, postverbal subject cooccur with the sentential negation adverb in compound tenses, as in (19a). The data in ( 19) fall under the Strict/Non-Strict NC parameter as defined in Zeijlstra's work and are not problematic for him in themselves. What is problematic is how they may be unified with the asymmetry between simple and compound tenses in ( 17)-( 18). In short, the Agree model of NC fails to predict North Italian varieties where NC depends on the context of insertion of the elements involved, making it impossible to assign them a fixed [uNeg] or [iNeg] feature. At the same time, the approach of Déprez does not have a better handle on these data than the Agree approach. On the contrary, in her framework, which is heavily dependent on the semantic interface value of n-items, there is even less reason to expect that syntactic locality of the kind described here would play any role.

Besides participial constructions, further variation with respect to NC depends on the relative position of negative adverbs and past participles. The following table show that NC is found more readily in varieties in which the adverbial negation precedes the participle (Table 3; p = .000033) or the adverb già 'already' (Table 4; p = .0448). Neither Zeijlstra nor Déprez's analyses can account for the data illustrated in Tables 34involving once again a correlation between positional and NC properties.

We are not the first to point out difficulties with the Agree approach, which by and large has become the standard approach to NC in minimalism. Indeed, some scholars present counterarguments based on the same general schema developed for North Italian in this section, namely that the same items can enter different NC patterns depending on their syntactic context of occurrence. For instance, [START_REF] Szabolcsi | Strict and non-strict negative concord in Hungarian: A unified analysis[END_REF] shows that the Hungarian negation nem cannot be characterized as [iNeg] or [uNeg] unambiguously since it may yield both Strict and Non-Strict NC depending on certain other syntactic factors.

Nevertheless, solutions proposed in the literature generally limit themselves to enriching Zeijlstra's approach. Thus, Szabolcsi, following Chierchia (2013), postulates both an abstract negation operator  and a NEG functional projection, which either hosts  or triggers itessentially encoding NC as a part of a functional hierarchy along cartographic lines.

Longobardi (2017) enriches the featural repertory of Zeijlstra postulating two features, namely

[NOT], i.e. the negative quantifier property, and [ANY], i.e. the NPI property, where the two positive values crucially combine in Romance n-items. In this way, he accounts for a considerable repertory of Romance facts, including basic patterns of Occitan and North Italo-Romance, but not for the contextual effects discussed in this section for Cantoira, as far as we can tell.

Though providing a systematic account of NC is beyond the scope of the present contribution, we conclude it by outlining some desiderata for such an account in the next section. In so doing we presuppose a conclusion that complex featural or cartographic systems of the type just briefly reviewed do not represent a viable prospect.

Desiderata for a theory of NC and ways forward

Like other scholars already quoted, [START_REF] Garzonio | Old Venetan and the typology of Negative Concord[END_REF], working on contemporary and historical Venetan varieties, spots the problem that "negative indefinites, negative adverbs and the negation marker can have different feature specifications in the same language". He resolves the issue that besets Zeijlstra as to why a [uNeg] element would be at all needed if the logical negation [iNeg] is covertly instantiated by proposing that on the contrary, "the pre-T negation marker [is] a type of repair strategy element which satisfies the visibility condition of Op being specified as [uNeg]. This condition must be satisfied at the edge of TP in languages with preverbal negation, like those I am considering here, but the proposal could be extended to systems with postverbal negation, assuming that languages can vary according to the locus where the visibility of the negative Op must be satisfied (e.g. vP)". For Garzonio, Non-Strict Concord languages are languages where "a negative indefinite in a spec-head relation with the inflected verb is sufficient to make the disembodied negative Op visible". 9

The formalization provided, however, is not systematic enough to make point by point comparison with standard Agree models easily possible. While we leave this work for future research, in what follows we sketch general guidelines for it, based on the assumption that locality domains are crucial when discussing cooccurrence and mutual exclusion patterns. This means in particular that reference to phases is necessarythough as the previous discussion shows, phases are not prominent in theories of NC. 10 9 Similarly, for [START_REF] Manzini | Grammatical Categories: Variation in Romance Languages[END_REF], also quoted by Garzonio, argumental NPIs can "subsume" the sentential negation, specifically when they are in a local (i.e. head-Spec) configuration; if none is present, the sentential negation must be inserted (the 'repair' mentioned by Garzonio). In unpublished work, Homer (2013), [START_REF] Homer | Remarks on a Language with No Overt Negation[END_REF] hint at similar conclusions at least for Strict NC languages like Haitian Creole. 10 In the original definition of Agree by Chomsky (2000: 122) only Minimality ("closest c-command") is defined as a locality condition on Agree. The next step is to recognize that conditions requiring or excluding sentential apply at the phase level. Fontane in ( 16) is a language where a negative adverb is always merged in the v phase independently of the presence or absence of n-items. In Cantoira in ( 17)-( 18 To model the facts in (21) without adopting repairs (hence potential backtracking), we propose that variation results from the way in which languages satisfy essentially two requirements. One is a requirement that a [Neg] feature on the phase head enters Agree with a

[Neg] feature within its Search domain. This can be construed as standard minimalist Agree with the phase head being the probe and n-items its goal. If the phase contains no n-item, then 11 A reviewer points out that both adverbial and clitic negation are in the edge of the phase and therefore within the WorkSpace when the next phase head is merged. What is relevant for the classification in ( 20) is the fact that the adverb is merged as a modifier of the v head, namely <Adv, v> if modification is modelled by Pair Mergeand similarly the clitic is merged with the I head [START_REF] Manzini | The clitic string as a Pair Merge sequence[END_REF].

a suitable clausal negative marker is merged, i.e. a negative clitic and/or a negative adverbthe availability of either or both depending on external (viz. historical) factors.

The second parameter is an EPP-like requirement at the edge of each phase. Variation depends on how the EPP-like requirement is satisfied when the phase contains an n-item.

Fontane-type languages always require a dedicated clausal negation marker in the v phase. The same is true of Czech in the C-I phase, whereas in Non-Strict NC languages the presence of an n-item at the edge of the phase (e.g. Spec, IP) suffices.

Assuming the phasal organization of NC in ( 21), we can also account for the contrast between simple and compound tenses in ( 17)-( 18). Recall that we have already suggested in section 4 that part of the solution may reside in ideas by [START_REF] Kayne | Toward a modular theory of auxiliary selection[END_REF], Manzini andSavoia (2005, 2011) that auxiliary-participle structures contain two lexical verbs, namely the auxiliary and the participle, the latter perhaps reduced to a vP, along the lines of ( 22). Structures of this type have been proposed before notably for (a subset of) causative constructions (Burzio 1986, Folli and[START_REF] Folli | Causation, obligation, and argument structure: On the nature of little v[END_REF].

(

) [vP [VP have [vP [VP V-ed]]]] 22
In the Cantoira examples the contrast between the structures in (17) containing a simple verb (non cooccurrence of negative adverb and n-items) and the auxiliary-participle structures in (18) (cooccurrence of any n-item) can be accounted for in phasal terms, along the lines of (23). In order to correctly process the examples, recall that the final position of the finite verb or auxiliary is in I (hence to the left of the adverb). Crucially the sentential negation adverb ɲiŋ is impossible in (23a) because it is unnecessary, being in the same phase as an n-item; 12 this is not true in (23b). [vP v [AspP ɲiŋ [VP ont [vP v [VP tʃama ɲyŋ]]]] ↑phase 2 ↑phase 1

12 Non-necessity leading to impossibility is a typical economy effect. A reviewer further points out that "compositionality", i.e. in general semantic interpretation, certainly does not require negation to be marked in all phases (or here all v phases). In our view, the phasal organization is a hallmark of the purely syntactic nature of NC and of its parameters (as sketched above).

The explanation of contrasts like (23) shows that the combination of negative elements in (20) with phase-based parameters in ( 21) is not a notational variant of previous accounts, but has some genuine explanatory potential. As one may expect, it also raises empirical issues of its own. One of them relates to Cantoira's data in (19). We tentatively propose that n-subjects move like operators through the phase edge, thus satisfying the negative EPP, see (24a).

Conversely, n-items that remain in situ (including inverted subjects) do not satisfy the EPP and, consequently, they co-occur with the adverbial clausal negation marker, see (24b). Languages with two negations are predicted to be a combination of the simpler languages considered. Take for instance French. This is of course a language where the negation of the v phase (pas) is only inserted in the absence of other n-items, rather like Cantoira in (21a). 13 At the same time the negation of the C phase (i.e. the ne clitic) is always insertedso that French is a Strict NC language in the C phase, rather like Czech in (21b). 14 At the present stage of our knowledge, we expect all logically possible combinations ought to be attested, though this needs to be checked.

Conclusions

13 Of course, unlike Cantoira, French does not lift the ban on pas in auxiliary-participle structures. We have reasons to believe that the relevant parameter may be independent of NC, and be connected rather to the structure of the participle. in Piedmontese varieties, unlike in French, participles can host functional material such as enclitics (Manzini andSavoia 2005, Pescarini 2021). This may point to a heavier functional structure, justifying the phase status attributed to them here. In the absence of this, we expect participial structure to behave like simple verb structures in French. 14 The well-known observation that that ne cannot negate by itself does not imply that ne is not a negative marker. Additionally, in normed French ne can negate certain predicates, e.g. (i) Il n'ose (pas) chanter en public. he not dares to sing in public (ii) Elle ne cesse (pas) de penser à la compétition.

She not ceases to think about competitors (iii) Il ne sait (pas) quand son frère reviendra.

He not knows when his brother will come back (iv) Lucie était exaspérée de ne (pas) pouvoir faire démarrer son ordinateur.

Lucie was exasperated to not be able to start her computer

  (I accomplished something) b. Non ho fatto niente. (It.) not I.have done n-thing 'I did nothing/I didn't do anything'

'

  They haven't eaten anything' Data like those in (13)-(14) are unremarkably similar to those of French. Nevertheless, the Finale Emilia variety differs from (Normed) French in that the presence of a preverbal n-marked subject forces the absence of the sentential negation clitic as well, as in (

  Before coming back briefly to the data in sections 3-4, let us consider a simpler parameter of Romance: some languages like Italian only have a clitic sentential negation non; other languages like Cantoira in (17)-(18) only have an adverbial sentence negation. Finally French combines the two possibilities. This hints at a phasal organization along the lines in and v phases: ne…pas (French)

(

  24) a. [CP ɲyŋ [IP e jøt [vP1 ɲyŋ (*ɲiŋ) jøt [vP2 miɲˈdʒa ɲyŋ]]]] b. [CP [IP e jøt [vP1 *(ɲiŋ) jøt [vP2 miɲˈdʒa ɲyŋ]]]]

  . Both French personne and Haitian Creole pèsonn originate from the reanalysis of the bare noun personne/pèsonn. Whereas the Haitian Creole pèsonn ends up occupying a low position in the DP, cf. (5a), French personne is forced to climb to D, as in (5b), since French forbids bare nouns. As a consequence, Haitian Creole pèsonn still behaves

			with two or more such elements. By contrast, in French
	NC amounts to quantifier absorption. For instance in (3d) the two Negative Concord Items
	(NCI) both contain a quantifier; these two are turned into a diadic quantifier binding two
	variables. Mutual exclusion with pas is then to be imputed to restrictions on resumptive
	quantification. Languages like English are easily accounted for as languages with
	quantificational negative items and no resumptive quantification.
	(5) a. [DP D	[NP pèsonn ]]	Haitian Creole
	b. [DP personne [NP N ]]	Contemporary French
	Before we consider how this model fares with respect to North Italian data, we turn to
	the other main syntactic model of NC, namely the modelling of NC by Agree proposed by

like a bare noun that is interpreted as a Negative Polarity Item, i.e. a free variable (with a lexical restrictor) bound by existential closure, precisely in the scope of the negation and of other relevant operators. By contrast, French personne is a determiner with quantificational force. On the basis of (5a), Haitian Creole is predicted to freely combine the exponent of the logical negation pa with any NPI, and in fact

  rule of Agree. For Chomsky,

	(8) a. *[TP Nessuno
	Agree is Minimal Search and Match, triggered by the non-interpretable nature of phi-feature
	sets (on C, on v). These need to be matched by interpretable sets, accessible to phase head
	probes under Minimality. Something of this sort is involved in NC -with one notable difference.
	In NC, interpretable Neg features [iNeg] c-command [uNeg]. Much of Zeijlstra's theoretical
	work (e.g. Zeijlstra 2012) is devoted to clarifying and justifying this move away from standard
	minimalist Agree; here we do not discuss it further, having noted the potential issues it raises.
	In all NC languages, therefore both in Italian and in Czech, NC-items are syntactically
	modelled as [uNeg] items. What varies is the sentential negation, which is sometimes [iNeg]
	and sometimes [uNeg]. In general, then, while for Déprez it is n-items that account for variation,
	for Zeijlstra it is sentential negations. In his terms, Italian non is [iNeg]; it is a negative operator
	that checks the [uNeg] features in its scope, thus licencing (7b). However in (7a) the subject n-
	item cannot agree with non since it is not in the c-command domain of the latter, cf. (8a). In
	that case the subject agrees with a covert [iNeg] operator in C, cf. (8b). 3

  , North Italian varieties have sentential negations comparable to those of French, sometimes doubled by a sentential negation clitic and sometimes negating alone.4 In other words, we have a considerable sample of languages where various combinations of sentential negation adverbs and sentential negation clitics with nmarked arguments are in principle possible. In this section and in the next one we will review patterns that prove problematic for either account reviewed so far.

		North Italian varieties that interest us in relation to the analysis of Déprez are those
	that have a sentential negation system including both a clitic and an adverb. Out of 171 varieties
	surveyed in Manzini and Savoia (2005, III: 259-272), 60 varieties present, to various extent,
	the co-occurrence of negative clitics (N1) and adverbial negators (N2). For several varieties,
				N2 + n-items	N2 + n-items
	N1(N2)		12	9
	N1N2 a. i	n	14 dɔram *(briʑa)	17
	(N1)N2 they NEG sleep 1	NEG	7
	N2	36 'They don't sleep'	65
	total b. i	63 nn a	*(briʑa) maɲa	98
		they NEG have NEG	eaten
		'They haven't eaten'

we have data concerning the combination or mutual exclusion of n-items with sentential negation adverbs

(Manzini and Savoia 2005, III: 259-272)

and with sentential negation clitics

(Manzini and Savoia 2005, III: 313-320)

.

5

More than half of the varieties exhibiting both N1 and N2, corresponding to lines 1-3 of table 1, allow the adverbial negator N2 to co-occur with n-items. The data reported in table 1 are plotted in Fig.

1

. Table 1. Number of languages per negation system (N1, N2) allowing/disallowing the co-occurrence of N2 with negative-marked arguments. Sample: 171 northern Italian varieties surveyed by Manzini and Savoia 2005, III: 259-272.

*Fig. 1. Number of languages per negation system (N1, N2) allowing (orange) or disallowing (blue) the co-occurrence of N2 with negative-marked arguments. Sample: 171 northern Italian varieties surveyed by Manzini and Savoia 2005, III: 259-272. The interesting varieties from our point of view are those where the clausal negation adverb excludes n-items. A relevant set of examples is in (13)-(14). The examples in (13) illustrate the adverbial negation briʑa obligatorily occurring in the absence of n-items. Those in (14) illustrate the mutual exclusion of briʑa and n-items. 6 (13) Finale Emilia (Emilia)

Table 2 .

 2 Number of languages allowing the co-occurrence of n-adv with n-items in simple vs compound tenses.The relevant data for present purposes are in (17) vs. (18) for the variety of Cantoira (Western Piedmont, technically a Franco-Provencal variety)where the sentential negation adverb is mutually exclusive with n-items in simple tenses (17), but not in compound tenses(18). More data, glossed and translated into English, can be found in[START_REF] Manzini | Grammatical Categories: Variation in Romance Languages[END_REF].

	(16) Fontane (Piedmont)
	a. ɲyŋ	i		dɾømu ɲent
	n-body there= sleep NEG
	'Nobody sleeps'
	b. ɲyŋ	i		aŋ ɲent dɾymi
	n-body there= have NEG slept
	'Nobody sleeps'
	c. ui	vɛŋ	ɲent ɲyŋə
	there= comes NEG n-body
	'There comes nobody'
	d. uj	a	ɲent vəŋgy ɲyŋə
	there=has NEG comes n-body
	'There has come nobody'

An example of uniform cooccurrence of the sentential negation adverb with n-items is provided by the variety of Fontane in (

16

), which allows the sentential negation adverb to cooccur with n-items both in object and in subject position, both in simple and in compound tenses.

7

Data like (

16

) are reminiscent of those of Haitian Creole and can be treated both by Déprez and by Zeijlstra.

7 Fontane has Occitan characters, from a dialectological point of view.

Let us consider how data like (

17

)-(

18

) could be accounted for in the framework of Zeijlstra. We may account for mutual exclusion of the sentential negation adverb ɲiŋ and nitems in (17), by assuming that ɲiŋ is [iNeg]though only an abstract [iNeg] can licence nitems, as

[START_REF] Penka | Negative Indefinites[END_REF]

proposes for French. But consider what happens in (18) under this

Table 3 .

 3 Number of languages in which adverbial negators (n-adv) co-occur with negative items and precede the past participle.

		n-adv > part	part > n-adv
	*n-adv + n-item	35	16
	n-adv + n-item	86	4

Table 4 .

 4 Number of languages in which adverbial negators (n-adv) co-occur with negative items and precede the adverb già 'already'.

		n-adv > già	già > n-adv
	*n-adv + n-item	12	11
	n-adv + n-item	59	18

It is not entirely clear why covert[iNeg] operator in C cannot license postverbal n-items in the same way in which overt operators such as senza 'without' in (i) do. (i) Ha parlato due ore senza (*non) dire niente.He.has spoken two hours without not say n-thing 'He spoke two hours without saying anything.'

The North Italian label is used here in a broad fashion encompassing varieties generally spoken within the political boundaries of Italy, but belonging to different dialectological groupings in situations of microcontact (especially Occitan and Franco-Provencal of Western Piedmont).

Data for the cooccurrence or mutual exclusion of sentential negations and n-items are reported separately(Manzini and Savoia 2005, I:

[62][63][64][65][66][67][68][69].

A mixed syntactic/semantic account à la[START_REF] Zeijlstra | Negation and Negative Dependencies[END_REF] does not improve on this conclusion, as far as we can tell.

In this contribution, we have argued that the best known accounts of NC meet problems with respect to North Italian varieties. The analysis of Déprez (2000Déprez ( , 2011) ) does not predict that the same n-items in different syntactic positions may or may not trigger Negative Concord, since for Déprez, NC parameters are connected to the quantificational force of NPIs/NCIs. The Agree analysis, first proposed by Zeijlstra (2004Zeijlstra ( , 2008)), but accepted by many other scholars, can account for the well-known divide between Strict and Non-Strict NC languages, but it has problems in capturing other syntactic configurations, yielding NC or lack thereofnotably those involving adverbial negation markers. Working towards the solution of those problems, we have sketched parameters requiring (or not) merger of a negative markerso called "sentential negation"in the C and/or the v phase depending on other n-items or an EPP-like edge constraint.


Rhodium-Catalyzed Asymmetric Transfer Hydrogenation/Dynamic Kinetic Resolution of 3-Benzylidene-Chromanones

Ricardo Molina Betancourt, Phannarath Phansavath* and Virginie Ratovelomanana-Vidal* PSL University, Chimie ParisTech, CNRS, Institute of Chemistry for Life and Health Sciences, CSB2D Team, 75005 Paris, France Supporting Information Placeholder ABSTRACT: A straightforward access to enantiomerically enriched cis-3-benzyl-chromanols from (E)-3-benzylidenechromanones was developed through Rh-catalyzed asymmetric transfer hydrogenation. This transformation allowed the reduction of both the C=C and C=O bonds and the formation of two stereocenters in high yields with excellent levels of diastereo-and enantioselectivities (up to >99:1 dr, up to >99% ee) in a single step through a dynamic kinetic resolution process using a low catalyst loading and HCO 2 H/DABCO as the hydrogen source.

Homoisoflavonoids are a widespread family of molecules, naturally occurring in plants, which possess a promising set of biological activities. [START_REF] Castelli | Homoisoflavonoids : Occurrence, Biosynthesis and Biological Activity[END_REF] Among those, antioxidant, antiinflammatory, antitumoral, antiviral, antibacterial and protective vascular actions can be cited as potential therapeutic indications. [START_REF] Cazarolli | Flavonoids : Prospective Drug Candidates[END_REF] The 3-benzyl-chromanol substructure is present in several molecules, for example CP-105,696, which possess a selective and potent LTB 4 receptor-inhibiting ability. [START_REF] Reiter | 3-Substituted-4-Hydroxy-7-Chromanylacetic Acid Derivatives as Antagonists of the Leukotriene B4 (LTB4) Receptor[END_REF] LTB 4 is a chemoattractant for granulocytes and is involved in several inflammatory diseases such as rheumatoid arthritis or asthma. An efficient and straightforward route to access enantiomerically enriched 3-benzyl-chromanols is thus highly desirable. In this context, Koch et al. reported the synthesis of an enantiomerically pure 3-benzyl-chromanol starting from the ketone precursor using a chemical resolution, after NaBH 4 reduction, esterification with t-Boc-L-tryptophan and hydrolysis of the resulting ester. [START_REF] Koch | +)-1-(3S,4R)-[3-(4-Phenylbenzyl)-4-Hydroxychroman-7-Yl]Cyclopentane Carboxylic Acid, a Highly Potent, Selective Leukotriene B4 Antagonist with Oral Activity in the Murine Collagen-Induced Arthritis Model[END_REF] Seo et al. later devised an asymmetric synthesis of cremastranone by using an asymmetric transfer hydrogenation (ATH) coupled with a dynamic kinetic resolution (DKR) of a 5,6,7-substituted homoisoflavanone catalyzed by Noyori's ruthenium complex [RuCl(p-cymene){(S,S)-Ts-DPEN}] or [RuCl(p-cymene){(R,R)-Ts-DPEN}], followed by TPAP oxidation of the resulting enantiomerically enriched alcohol. [START_REF] Heo | Enantioselective Synthesis of Homoisoflavanones by Asymmetric Transfer Hydrogenation and Their Biological Evaluation for Antiangiogenic Activity[END_REF] The ATH reaction proceeded using a 3:1 mixture of DBU/HCO 2 H as the hydrogen source, and a catalyst loading of 30 mol% to achieve full conversion. Subsequent oxidation of the alcohol with TPAP gave the desired (R) and (S)cremastranone without racemization, allowing confirmation of the absolute configuration of the natural product as (R) and showing that the anti-angiogenic effect of the (S)-isomer was superior to the natural (R)-form.

Scheme 1. Catalytic asymmetric reduction of 3-substituted chromanones

The authors used the same strategy for the total synthesis of several 5,7,8-trioxygenated chroman-4-ones and homoisoflavonoids. [START_REF] Kwon | Total Synthesis of Naturally Occurring 5,7,8-Trioxygenated Homoisoflavinoids[END_REF] In the context of our ongoing studies directed toward the development of efficient methods for the asymmetric reduction of functionalized ketones 7 and in order to access a wide range of 3-benzyl-chromanol derivatives, we report herein the first rhodium-catalyzed asymmetric transfer hydrogenation of

HCO 2 H/DABCO R O OH R or (S)-cremastranone (R)-cremastranone or (R,R)-[Ru] (30 mol%) or TPAP, NMO X Y Y X X = OH, Y = H TPAP, NMO X = H, Y = OH X = Y = O X = Y = O
3-benzylidene-chromanones that efficiently reduces both the C=C and C=O bonds in a single synthetic step and provides in good yields the targeted molecules with excellent levels of diastereo-and enantioselectivity through a dynamic kinetic resolution process (DKR). [START_REF] Westermeyer | Synthesis of Enantioenriched -Hydroxy--acetal Enamides by Rhodium-catalyzed Asymmetric Transfer Hydrogenation[END_REF] To investigate the proposed ATH-DKR, racemic (E)-3benzylidene-chromanone 1a [START_REF] Thapa | Synthesis of 2,4-Diaryl Chromenopyridines and Evaluation of Their Topoisomerase I and II Inhibitory Activity, Cytotoxicity, and Structure-Activity Relationship[END_REF][START_REF] Hammam | Synthesis of Novel Tricyclic Heterocyclic Compounds as Potential Anticancer Agents Using Chromanone and Thiochromanone as Synthons[END_REF] was subjected to the asymmetric reduction using several organometallic catalysts in acetonitrile at 50 °C for 24 h (Table 1). The HCO 2 H/Et 3 N (5:2) azeotropic mixture (5 equiv) was first used as the hydrogen source in the presence of 0.5 mol% of rhodium or ruthenium complexes (Table 1, entries 1-3). These conditions led to a full conversion with all the tested complexes. The ATH using oxo-tethered ruthenium catalyst (R,R)-A 11 occurred with a modest diastereomeric ratio of 77:23 in favor of the cis alcohol 2a, which was obtained in 84% yield and >99% ee (Table 1, entry 1). With the [RuCl(p-cymene){(R,R)-Ts-DPEN}] complex (R,R)-B, [START_REF] Matsumura | Asymmetric Transfer Hydrogenation of α, β-Acetylenic Ketones[END_REF] a high yield (92%) and high levels of diastereo-and enantioinductions were observed (Table 1, entry 2, 92:8 dr, 95% ee). We were delighted to find that the home made (R,R)-C 12 containing an (R,R)-TsDPEN ligand tethered to the ancillary η 5 -arene ligand outperformed the previous catalysts by yielding a diastereomeric ratio of 97:3 and 99% ee (Table 1, entry 3). We next chose to screen a variety of bases and replaced triethylamine with DBU in the hydrogen source mixture. The use of a HCO 2 H/DBU (2:1) combination pleasingly allowed a slight increase of the yield of 2a with both (R,R)-B and (R,R)-C, the latter still giving the best stereoselectivities (Table 1, entries 4 and5). Based on this encouraging series of results, the rhodium complex (R,R)-C was chosen as the catalyst for this study.

The investigations continued with the screening of the solvent, the catalyst loading (S/C) and the nature of the hydrogen donor (Table 2). Several solvents such as CH 3 CN, CH 2 Cl 2 , THF, toluene, AcOEt, i-PrOH, and MeOH performed well (Table 2, entries 1-7). High yields of 84-95% were obtained in these solvents with diastereomeric ratios ranging from 90:10 to 97:3 and enantioselectivities of 99% to >99% ee, with acetonitrile giving the best results. ,(R,R)-C (0.5 mol%), hydrogen donor (5 equiv), solvent (1.5 mL), 50 °C, 24 h. b Isolated yield of 2a. c Determined by 1 H NMR of the crude product after the ATH reaction. d ee for the cis product determined by SFC analysis. e 0.25 mol% of (R,R)-C were used. f 0.1 mol% of (R,R)-C were used. g 0.1 mL of water were added. h 3 equiv of i-PrOH/KOH were used.

Next, the S/C ratio was progressively lowered (Table 2, entries 8 and 9). Increasing the S/C to 400 did not affect the outcome of the ATH reaction. However, using a S/C of 1000 had a detrimental effect on the yield, which dropped to 43%. To complete the optimization of the reaction parameters, other hydrogen sources were examined. Formate salts such as HCO 2 NH 4 and (HCO 2 ) 2 Ca led to lower yields with a significant unfavorable impact on the stereoselectivity in the latter case (Table 2, entries 10-11). Whereas using potassium hydroxide in isopropanol failed to afford any conversion (Table 2, entry 12), the hindered 1,4-diazabicyclo[2.2.2]octane (DABCO) gave excellent results allowing the diastereoselectivity to reach 99:1 dr while maintaining the enantioselectivity at >99% ee (Table 2, entry 13). From this survey, the optimized conditions were set as follows: (R,R)-C (0.5 mol%) as the precatalyst, HCO 2 H/DABCO (2:1) (5 equiv) as the hydrogen source in CH 3 CN solvent at 50 °C.

Having identified an effective stereoselective method to set the vicinal stereocenters and being amenable to a dynamic kinetic resolution process (DKR), we explored the scope and limitations of the asymmetric reduction on a series of 3benzylidene-chromanone derivatives that could be utilized in this novel DKR transformation (Table 3). Good results were obtained with a wide range of arene substitution by varying the position (ortho, meta or para) of the methoxy group on the aryl ring of the benzylidene moiety, and compounds 2b-2d were formed in 92-95% yields, 99:1 dr and enantioselectivities up to >99% ee (Table 3, entries 2-4). Other 3-benzylidenechromanone derivatives bearing either electron-donating or electron-withdrawing groups were efficiently reduced to the corresponding cis alcohols with good yields up to 93% and high levels of diastereo-and enantioselectivities (Table 3, entries 5-10, up to 99:1 dr, up to >99% ee). Interestingly, a bulky substituent such as a naphthyl group (Table 3, entry 11) as well as a heteroaryl substituent such as a furyl subunit or biphenyl substituents (Table 3, entry 12 and 13 respectively) were well-tolerated. Importantly, the reaction was not limited to arylchromanone derivatives and an alkenyl substituted chromanone was also accommodated in this transformation (Table 3, entry 14). In this case, the reduction proved to be chemoselective of the C=C bond located next to the carbonyl group yielding the corresponding cis-chromanol in good yield (69%), good diastereoinduction (94:6 dr) and excellent enantiocontrol (>99% ee).

The absolute configuration of compound 2g was unambiguously determined as (R,R) by X-ray crystallographic analysis, and by analogy we conjectured that the remainder of the ATH products followed the same trend. In addition, the (S,S)alcohols 2o and 2p could be readily prepared as well by using the (S,S)-isomer of the rhodium complex C instead of the (R,R)-enantiomer. In both cases the reduced compounds were obtained with results comparable to those obtained for the parent alcohols 2a and 2b, respectively (Table 3, entries 15-16 vs entries 1-2).

The utility of the developed reaction was illustrated by its performance on gram-scale. Compound 1n was subjected to the ATH-DKR under the same reaction conditions to provide 2n in 89% yield, 99:1 dr and >99% ee (Scheme 2). Furthermore, compound 2h was post-functionalized into 4 in 80% yield and no loss of dia-and enantioselectivity by protecting the alcohol group with a tert-butyl-di-methyl silane group followed by a Suzuki-Miyaura cross-coupling by using Pd(OAc) 2 , cataCXium A as ligand, K 2 CO 3 as a base, 4methoxyphenylboronic acid and DMF as solvent. In summary, the practical rhodium-catalyzed asymmetric transfer hydrogenation of 3-benzylidene chromanones allows reduction of two double bonds in a single step in a stereocontrolled manner. The unique combination of Rh(III) complex developed in the group and formic acid/DABCO (2:1) as hydrogen source enables at low catalyst loading under mild conditions, the facile reductive dynamic kinetic resolution of 3-benzylidene chromanones to access the corresponding cis-3-benzyl chromanols in high yields and excellent stereoselectivities (up to >99:1 dr, up to >99% ee). This efficient and straightforward catalytic route provides access to synthetically useful chromanol derivatives and valuable chroman pharmacophores as well and tolerates a broad range of functionalities.

  crystallography of 2g. Displacement ellipsoids are shown at the 30% probability level. a Conditions: 1a-n (0.79 mmol), (R,R)-C (0.5 mol%), 5 equiv of HCO2H/DABCO (2:1), MeCN (1.5 mL). b Isolated yield, complete conversion in all cases. c Determined by 1 H NMR of the crude product after the ATH reaction. d ee for the cis product determined by SFC analysis. e The ATH reaction was performed with complex (S,S)-C under otherwise identical conditions.

  Scheme 2. Post-functionalization and Scale-Up

Table 1 . Catalyst screening for the ATH of 1a a

 1 Isolated yield, complete conversion in all cases. c Determined by 1 H NMR of the crude product after the ATH reaction. d ee for the cis product determined by SFC analysis.

	entry	cat.	HCO2H/Base	yield of 2a b (%)	dr c	ee d (%)
	1	(R,R)-A	HCO2H/Et3N	84	77:23	>99
	2	(R,R)-B	HCO2H/Et3N	92	92:8	95
	3	(R,R)-C	HCO2H/Et3N	91	97:3	99
	4	(R,R)-B	HCO2H/DBU	96	93:7	98
	5	(R,R)-C	HCO2H/DBU	95	97:3	>99

a Conditions: 1a (0.79 mmol), cat. (0.5 mol%), 5 equiv of HCO2H/Et3N (5:2) or HCO2H/DBU (2:1), MeCN (1.5 mL), 50 °C.

b

Table 2 . Optimization of the reaction conditions a

 2

	entry solvent	hydrogen donor	yield b (%)	dr c	ee d (%)
	1	CH3CN	HCO2H/DBU (2:1)	95	97:3	>99
	2	CH2Cl2	HCO2H/DBU (2:1)	94	92:8	99
	3	THF	HCO2H/DBU (2:1)	92	96:4	>99
	4	toluene	HCO2H/DBU (2:1)	84	96:4	>99
	5	AcOEt	HCO2H/DBU (2:1)	87	97:3	>99
	6	i-PrOH	HCO2H/DBU (2:1)	88	90:10	>99
	7	MeOH	HCO2H/DBU (2:1)	95	93:7	99
	8 e	MeCN	HCO2H/DBU (2:1)	94	96:4	>99
	9 f	MeCN	HCO2H/DBU (2:1)	43	97:3	>99
	10	MeCN	HCO2NH4	49	92:8	98
	11 g	MeCN	(HCO2)2Ca	63	74:26	89
	12 h	MeCN	i-PrOH/KOH	-	-	-
	13	MeCN	HCO2H/DABCO (2:1)	96	99:1	>99
	a Conditions: 1a (0.79 mmol)

Table 3 . Substrate scope of the ATH/DKR of 1a-1n a

 3

			O		Cat. (0.5 mol%)		OH	Ph
					HCO 2 H/base
			O		MeCN, 50 °C, 24 h		O
			1a					2a
	Ph	TsN	H N Ru	Cl O	Ru TsN N Ph H	Cl H	MeO	Rh TsN N Ph	Cl H
			Ph		Ph				Ph
		(R,R)-A		(R,R)-B			(R,R)-C

Table 3 (contd.)

 3

ACKNOWLEDGMENT

This work was supported by the Ministère de l'Education Nationale, de l'Enseignement Supérieur, de la Recherche et de l'Innovation (MESRI) and the Centre National de la Recherche Scienti-fique (CNRS). We gratefully acknowledge the MESRI for a grant to R. M. B. We thank J. Forté (Sorbonne Université, Paris) for solving the X-ray structure of compound 2g and Dr C. Fosse (Chimie ParisTech) for the mass spectroscopy analysis.

ASSOCIATED CONTENT Supporting Information

The Supporting Information is available free of charge on the ACS Publications website.

Experimental procedures, compound characterization data, NMR spectra and SFC data (PDF)

CCDC 2048735 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing da-ta_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033

AUTHOR INFORMATION

Corresponding Author *E-mail: phannarath.phansavath@chimieparistech.psl.eu. *E-mail: virginie.vidal@chimieparistech.psl.eu.

Notes

The authors declare no competing financial interest.