Structure and properties of novel M(dmit)2 salts with the Me3N+TEMPO cation radical (Me3N+TEMPO = N,N,Ntrimethyl(1oxyl2,2,6,6tetramethylpiperidin4yl)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; dmit2− = 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 × 10−3 S cm−1, which is rather high for an integral oxidation state salt.