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Enantiopure Conducting Salts of Dimethylbis(ethylenedithio)tetrathiafulvalene (DM‐BEDT‐TTF) with the Hexachlororhenate(IV) Anion
Author(s) -
Pop Flavia,
Allain Magali,
AubanSenzier Pascale,
MartínezLillo José,
Lloret Francesc,
Julve Miguel,
Canadell Enric,
Avarvari Narcis
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201400125
Subject(s) - tetrathiafulvalene , triclinic crystal system , chemistry , pyrazine , crystallography , enantiopure drug , radical ion , crystal structure , molecule , paramagnetism , ion , stereochemistry , organic chemistry , condensed matter physics , physics , enantioselective synthesis , catalysis
Abstract The enantiopure radical cation salts [( S , S )‐DM‐BEDT‐TTF] 4 [ReCl 6 ] ([( S , S )‐ 1 ] 4 [ReCl 6 ]) and [( R , R )‐DM‐BEDT‐TTF] 4 [ReCl 6 ] ([( R , R )‐ 1 ] 4 [ReCl 6 ]) [DM‐BEDT‐TTF = dimethylbis(ethylenedithio)tetrathiafulvalene] have been prepared by electrocrystallization of the chiral precursor DM‐BEDT‐TTF in the presence of NBu 4 [ReCl 5 (pyrazine)] (NBu 4 = tetra‐ n ‐butylammonium cation; pyz = pyrazine) as supporting electrolyte. The single‐crystal X‐ray analysis shows that the compounds crystallize in the triclinic system, non‐centrosymmetric space group P 1, and that the donors arrange in parallel columns. The four independent donor molecules possess approximate charges of +1, +1/2, +1/2 and 0, according to the structural parameter analysis and band‐structure calculations, which also support the semiconducting behaviour of the materials. The rhenium(IV) ion in both compounds is six‐coordinate with six chloro atoms that describe a slightly distorted octahedral environment with Re–Cl distances that cover the short range 2.348–2.374 Å. Magnetic measurements on polycrystalline samples of [( S , S )‐ 1 ] 4 [ReCl 6 ] and [( R , R )‐ 1 ] 4 [ReCl 6 ] have been investigated in the temperature range 2–295 K. They are practically identical and confirm the presence of high‐spin S = 3/2 [ReCl 6 ] 2– isolated monomers together with a Pauli paramagnetism, typical of this kind of system. The magnetic susceptibility data are thoroughly reproduced over the whole temperature range with a simple model of isolated S = 3/2 ions with a zero‐field splitting plus a temperature‐independent paramagnetism (TIP), and the best‐fit parameters being g Re = 1.875(2), | D | = 4.50(3) cm –1 and TIP = 3630(20)×10 –6 cm 3 mol –1 (2 D is the energy gap between the M S = ±3/2 and M S = ±1/2 Kramers doublets).