Syntheses and structures of diorgano(halo- orpseudohalo-)(1,3-dithiole-2-thione-4,5-dithiolato)-stannates (1-), [Q][R2SnX(dmit)] (Q=onium cation; X=halide orpseudohalide)

Abstract Ionic compounds, [Q] [R 2 SnX(dmit)][dmit=1,3-dithiole-2-thione-dithiolate; Q=1,4-dimethylpyridinium or tetraalkylammonium; R=Phor alkyl; X=Cl, Br, I, NCS, NCSe, or N 3 ] have been obtained by (a) from R 2 SnX 2 and [Q] 2 [Zn(dmit) 2 ] in the presence of excess QX,(b) from halide exchange reactions in acetone solution between [Q] [R 2 SnCl(dmit)]and a halide or pseudohalide source, or (c) by addition of QX to [R 2 Sn(dmit)]. Crystalstructure determinations of [NEt 4 ] [Ph 2 SnI(dmit)] and [1,4-Me 2 pyridiniuml [Ph 2 SnBr(dmit)] as well as of the mixed halides, 1a , 1b , 4a , 2 [Ph 2 SnCl n I 1− n (dmit)] ( n =0.57, 0.42 or0.22), indicated that the tin atoms have distorted trigonal bipyramidal geometries in the anions,with the X ligand and a dithiolato atom in the axial sites. The [R 2 SnX(dmit)] − anions remain essentially intact in organic solvents, but lose X − on extractionwith H 2 O to give the neutral species, R 2 Sn(dmit).