Synthesis and crystal structure of charge-transfer salt (BEDT-TTF) [Pt(mnt)2]

The synthesis and crystal structure of the title organic charge-transfer salt (BEDT-TTF)[Pt(mnt)(2)] (BEDT-TTF=bis(ethylenedithio) tetrathiafulvalene; mnt=cis- 3,4-dimercapto-2-butenedinitrile) is described. The salt crystallizes in the P1 space group with a=6.728(2) Angstrom, b=7.371(2) Angstrom, c=13.596(4) Angstrom, alpha=97.904(5)degrees, beta=90.114(5)degrees, and gamma=108.147(5)degrees. The stoichiometry between BEDT-TTF and [Pt(mnt)(2)] is 1:1. The bond length of the central C=C bond in a BEDT-TTF ion is 1.398 (16) Angstrom, indicating an oxidation state of +1 in BEDT-TTF ion. The structure consists of layers of BEDT-TTF and Pt(mnt)(2) along the c axis. Within each layer, both BEDT-TTF and Pt(mnt)(2) ions form segregated stacks. The stacking is not in a face-to-face manner, but instead, is through a side-by-side arrangement along the a axis, with closest S...S contacts of 3.461(3) Angstrom between neighboring BEDT-TTF ions. The structure is consistent with the semiconducting behavior found in the solid.