Mixed-Valence Conductors from Ni Bis(diselenolene) Complexes with a Thiazoline Backbone
Résumé
Highly conducting, mixed-valence, multi-component nickel bis(diselenolene) salts were obtained by electrocrystallization of the monoanionic species [Ni(Me-thiazds)(2)](-1) (Me-thiazds: N-methyl-1,3-thiazoline-2-thione-4,5-diselenolate), with 1:2 and 1:3 stoichiometries depending of the counter ion used (Et(4)N(+) and nBu(4)N(+) vs Ph(4)P(+), respectively). This behavior strongly differs from that of the corresponding monoanionic dithiolene complexes whose oxidation afforded the single component neutral species. This provides additional rare examples of mixed-valence conducting salts of nickel diselenolene complexes, only known in two examples with the dsit (1,3-dithiole-2-thione-4,5-diselenolate) and dsise (1,3-dithiole-2-selone-4,5-diselenolate) ligands. The mixed-valence salts form highly dimerized or trimerized bi- and trimetallic units, rarely seen with such nickel complexes. Transport measurements under a high pressure (up to 10 GPa) and band structure calculations confirm the semiconducting character of [Ph(4)P][Ni(Me-thiazds)(2)](3) and the quasi metallic character of [Et(4)N][Ni(Me-thiazds)(2)](2) and [NBu(4)](x)[Ni(Me-thiazds)(2)](2) salts (0 < x < 1).
Domaines
Chimie
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Licence : Copyright (Tous droits réservés)