MAIN GROUP METAL 1,3-DITHIOLE-2-THIONE-4,5-DITHIOLATE (DMIT) COMPOUNDS .2. SYNTHESIS AND STRUCTURES OF TETRABUTYLAMMONIUM BUTYL-BIS(1,3-DITHIOLE-2-THIONE-4,5-DITHIOLATO)STANNATES, AND TETRABUTYLAMMONIUM PHENYL-BIS(1,3-DITHIOLE-2-THIONE-4,5-DITHIOLATO)STANNATES, [BU4N][RSN(DMIT)2] (R = BU OR PH)

Structures have been determined for [Bu4N][RSn(DMIT)2] (III; R = Bu and IV; R = Ph), obtained from [Bu4N]2[Zn(DMIT)2] and RSnCl3. These complexes are isostructural. In the spirocyclic anions, the tin atoms are pentacoordinate and have geometries between trigonal bipyramidal (TBP) and rectangular pyramidal: the distortions away from TBP geometry are calculated to be ca. 48 and 70% for II and IV respectively. The S atoms in the chelate ligands form the quasi-basal planes with the R groups in axial sites. The DMIT ligands, while individually planar, are not coplanar: the angles between the DMIT mean planes are 19.2 and 10.8-degrees for III and IV respectively. The anions are packed side by side in the c direction with S ... S separations close to the sum of the van der Waals radii. In the a and b directions, there are arrays of alternating cation and anion units.