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) Å, b = 7.371(2) Å, c = 13.596(4) Å, = 97.904(5)°, = 90.114(5)°, and =108.147(5)°. 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) Å, 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 SS contacts of 3.461(3) Å between neighboring BEDT-TTF ions. The structure is consistent with the semiconducting behavior found in the solid.