Structure and properties of novel M(dmit)2 salts with the Me3N+-TEMPO cation radical (Me3N+-TEMPO = N,N,N-trimethyl(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)ammonium)

Salts of the Me3N+-TEMPO cation radical (Me3N+-TEMPO = N,N,N-trimethyl(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)ammonium) with I- and PF6- are prepared. Their crystal structure and magnetic properties are reported (antiferromagnetically coupled dimers for (Me3N-TEMPO)I and antiferromagnetically coupled chains for (Me3N-TEMPO)PF6). The Me3N+-TEMPO magnetic cation radical is associated with M(dmit)(2) (M = Ni, Pd; dmit(2-) = 1,3-dithiole-2-thioxo-4,5-dithiolato) to afford the divalent (Me3N-TEMPO)(2)[M(dmit)(2)] (M = Ni, Pd) salts and the monovalent (Me3N-TEMPO)[Ni(dmit)(2)] salt. The crystal structures of (Me3N-TEMPO)(2)[M(dmit)(2)] (M = Ni, Pd) and (Me3N-TEMPO)[Ni(dmit)(2)] are determined. In the (Me3N-TEMPO)(2)[M(dmit)(2)] salts, a unique, non planar, chair conformation of the M(dmit)(2) molecule is observed. These salts display conventional Curie behaviour. The (Me3N-TEMPO)[Ni(dmit)(2)] salt exhibits a single-crystal room-temperature conductivity of 4 x 10(-3) S cm(-1), which is rather high for an integral oxidation state salt.