Radical Cation Salts of Tetramethyltetrathiafulvalene (TM-TTF) and Tetramethyltetraselenafulvalene (TM-TSF) with Chlorocyananilate-Based Anions

Ashoka Sahadevan S.

First

;Abherve A.;Monni N.;Auban-Senzier P.;Cui H.;Kato R.;Mercuri M. L.

;Avarvari N.

2020-01-01

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Abstract

Electrocrystallization of tetramethyltetrathiafulvalene (TM-TTF) and tetramethyltetraselenafulvalene (TM-TSF) with chlorocyananilate monoanion or/and tris(chlorocyananilato)ferrate(III) in THF/DCM solvent mixtures yielded a salt formulated as [TM-TTF]4[K(HClCNAn)4] (1) with the former and π-d hybrid systems, formulated as [TM-TTF]5[Fe(ClCNAn)3]·2CH2Cl2 (2) and [TM-TSF]3[Fe(ClCNAn)3]·0.5CH2Cl·2.5H2O (3), respectively, with the latter. Compound 1 shows segregation of TM-TTF donor molecules and K(HClCNAn)4 anionic clusters in the bc plane. The donor molecules are present as mixed-valence dimers and show a β′ packing arrangement. Compounds 2 and 3 consist of hybrid organic/inorganic structures with no segregation of [Fe(ClCNAn)3]3- anionic complexes and organic TM-TTF/TM-TSF donors. In the structure of compound 3, TM-TSF dimers are trapped between anilate units of metal complexes of opposite chirality. Furthermore, tetrameric donor motifs and solvent molecules of crystallization complete the structure. Single-crystal conductivity measurements on compounds 1 and 2 show semiconducting behavior with room-temperature conductivity values of 5 × 10-5 and 2 × 10-4 10 S cm-1 and activation energies of 1960 and 1900 K, respectively. Under high pressure, compound 2 remains a semiconductor, yet its room-temperature conductivity value strongly increases up to 0.2 S cm-1 at 9.8 GPa.