STRUCTURAL STUDIES ON SOME IODOANTIMONATE AND IODOBISMUTHATE ANIONS

The reaction between BiI3 and two equivalents of dmpu (dmpu = N,N'-dimethylpropylene urea) in thf (tetrahydrofuran) or toluene affords dark red crystals of the complex [Bi(dmpu)(6)][Bi3I12] which was characterised by X-ray crystallography and consists of octahedral [Bi(dmpu)(6)](3+) cations and [Bi3I12](3-) anions both with ($) over bar 3 symmetry. An analogous reaction between SbI3 and dmpu afforded orange crystals of what is probably a hydrolysis product, [C5NH6](2)[H(dmpU)(2)] [Sb2I9], which was also characterised by X-ray crystallography and contains a face-shared biocathedral [Sb2I9](3-) anion with two pyridinium cations and a hydrogen bonded [H(dmpu)(2)](+) cation. [CH2 = C(C6H4-4-NO2)CH(2)NMe(3)]I and one equivalent of SbI3 afforded the orange crystalline complex [CH2=C(C6H4-4-NO2)CH(2)NMe(3)](3)[Sb2I9] an X-ray crystallographic study of which revealed a face-shared bioctahedral [Sb2I9](3-) anion similar to that present in [C5NH6](2)[H(dmpu)(2)][Sb2I9]. Four equivalents of BiI3 and [CH2 = C(C6H4-4-NO2)CH(2)NMe(3)]I afforded the complex [CH2 = C(C6H4-4-NO2)CH(2)NMe(3)](3)[Bi3I12], the [Bi3I12](3-) anion being essentially identical to that encountered in [Bi(dmpu)(6)][Bi3I12]. [CH3(CH2)(2)COS(CH2)(2)NMe(3)]I and four equivalents of SbI3 yielded orange crystals of the complex [CH3(CH2)(2)COS(CH2)(2)NMe(3)](4)[Sb8I28] which was also characterised by X-ray crystallography and shown to contain a new structural type of [E(8)X(28)](4-) anion (E = As, Sb, Bi; X = halide).