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

Ionic compounds, [Q] [R2SnX(dmit)] [dmit = 1,3-dithiole-2-thione-dithiolate; Q = 1,4-dimethlpyridinium or tetraalkylammonium R = Ph or alkyl; X = Cl, Br, I, NCS, NCSe, or N-3] have been obtained by (a) from R2SnX2 and [Q](2)[Zn(dmit)(2)] in the presence of excess QX, (b) from halide exchange reactions in acetone solution between [Q] [R2SnCl(dmit)] and a halide or pseudohalide source, or (c) by addition of QX to [R2Sn(dmit)]. Crystal structure determinations of [NEt4] [Ph2SnI(dmit)] and [1,4-Me(2)pyridinium] [Ph2SnBr(dmit)] as well as of the mixed halides. [1,4-Me(2)pyridinium] [Ph2SnCln,I(1-)n(dmit)] (n = 0.57, 0.42 or 0.22), indicated that the till atoms have distorted trigonal bipyramidal geometries in the anions: with the X ligand and a dithiolato atom in the axial sites. The [R2SnX(dmit)](-) anions remain essentially intact in organic solvents, but lose X- on extraction with H2O to give the neutral species, R2Sn(dmit). (C) 1998 Elsevier Science Ltd. All rights reserved.