Roger Carlier

2,5-Bis(1,4-dithiafulven-6-yl) furans, thiophenes and N-methyl pyrroles as extended analogues of tetrathiafulvalene

Abstract The title compounds are synthesized by Wittig or Wittig-Horner reactions between the corresponding furan, thiopen and N-methyl-pyrrole-2,5-dicarbaldehydes and P-reagents W or P bearing the 1,3-dithiol-2-ylidene moiety adequately substituted at the 4,5-positions; thanks to usual and thin layer cyclic voltammetry, they are shown to possess good π-donor abilities.

M(hfac)2(TTF–py)2 (M = CuII, MnII; hfac = hexafluoroacetylacetonate and TTF–py = 4-(2-tetrathiafulvalenyl-ethenyl)pyridine): a new approach for π–d interactions in conducting and magnetic molecule based materials

Abstract The new coordination complexes M(hfac)2(TTF–py)2 (M = CuII, MnII) in which the paramagnetic transition metal and the organic donor are covalently linked through delocalized π system are prepared aiming with a new approach for the occurrence of π–d interactions in conducting and magnetic molecule based materials. The structures, magnetic properties and electrochemical properties were investigated. X-ray structure analysis revealed its structure is favorable for electrical conductivity.

La deprotection electrochimique des amines : (II) - Problèmes posés par la coupure cathodique des p.toluéne sulfonamides

Abstract The deprotection of amines may be conducted via the cathodic cleavage of the corresponding sulfonamides. However, the selectivity of the reaction depends on parameters such as the tendency of the sulfonamide in the absence of proton donors to be decomposed into imine at the cathodic interface. The problem is discussed as a function of the molecular structure of the starting sulfonamide. Results on simple sulfonomides are applied successfully in the deprotection of polysulfonamides and may allow the synthesis of new polyazaligonds.

Electrosynthesis and redox behavior of vinylogous TTF displaying strong conformational changes associated with electron transfers

Abstract The redox properties of a series of substituted vinylogous tertrathiafulvalenes (TTF) prepared by oxidative coupling of 1,4-dithiafulvenes (DTF) have been investigated in acetonitrile and dichloromethane. The different steps of the electrodimerization mechanism have been characterized: fast electron transfer, coupling between two cation-radicals and slow deprotonation. Through the substituent choice of DTF, it is possible to control the relative stabilities of the different redox species of the electrogenerated vinylogous TTF. According to the nature and position of the substituent, the structural changes induced by the steric interactions lead to a compression of potential (where the second electron is easier to remove than the first one), or on the contrary to a large increase of the separation between the first and second oxidation potentials (by comparison with similar molecules without steric hindrance). Density functional modeling calculations and detailed analysis of the electrochemical behavior have been used to rationalize the substituent effect. A good agreement with the occurrence of an EE mechanism in which the electron transfer is concerted with the conformation changes is found. The inner reorganization energies are low (0.35–0.45 eV) allowing a fast passage between the different conformations during the electron transfers.

Dication charge transfer salts of TTF vinylogues

TTF vinylogues were electrochemically synthesized and dication charge transfer salts were isolated. Important conformational changes between the neutral and oxidized states were observed by X-ray structure analysis.

Cathodic synthesis of powerful electron π-donors including dithiadiazafulvalenes

Intramolecular coupling of bis(2-ethylthio-1,3-thiazolium) salts upon electrochemical reduction leads to dithiadiazafulvalenes (DTDAF). These novel π-electron donor molecules show extremely high donating properties compared to their sulfur analogues, tetrathiafulvalenes (TTF). In addition we report that a DTDAF precursor substituted by a dithiafulvenyl group undergoes dimerization upon oxidation to afford vinylogous TTF. Cathodic coupling of the corresponding tetra(2-ethylthio-1,3-thiazolium) salt leads to a new donor including two different donor families: DTDAF and vinylogous TTF.

Crown-ether annelated dithiadiazafulvalenes

Abstract The synthetic approaches towards crown-ether annelated dithiadiazafulvalenes (DTDAF) are described. As evidenced by electrochemistry, the reaction of N , N ′-bridged-bisthiazolium salts in basic medium favors the formation of the DTDAF via an intramolecular coupling while the reaction of N , N ′-bridged-bisthiazoline selone with trivalent phosphorus derivative leads to the donor core via an intermolecular coupling. The complexation of various metal cations on these crown-ether annelated DTDAF is investigated by electrochemistry.

Tetrathiafulvalenophanes and their electrochemical behavior

Tetrathiafulvalenophane, vinylogous tetrathiafulvalenophanes and their redox behavior have been studied. The effect of cations on tetrathiafulvalenophane incorporating oxacrown ether has been investigated by electrochemistry.

Cation radical salts of the tetrathiafulvalene series : fast mixed valence detection by thin layer cyclic voltammetry

Abstract The detection and evaluation of mixed valence states in cation radical salts (CRS) of the tetrathiafulvalene (TTF) series are readily achieved by using thin layer cyclic voltammetry (TLCV) with an internal coulometric reference. The method has proved to be valid for the mixed valence determination of the following typical well known CRS : TTFBr 0.75 , TMTTF(PF 6 ) 0.5 , TMTSF(PF 6 ) 0.5 , BEDTTTF(PF 6 ) 0.5 , BEDTTTF(BF 4 ) 0.5 .

Electrochemical oxidative coupling of 1,4-bis(1,4-dithiafulven-6-yl)benzene cyclophanes

The synthesis and the redox behavior of π-redox cage-like molecules incorporating one or two 1,4-bis(1,4-dithiafulven-6-yl)benzene are reported. The shape of the voltammograms indicates that 6 and 9 undergo an oxidative coupling. The X-ray crystal structure of compound 6 is presented.