Structural Studies on some Iodoantimonate and Iodobismuthate Anions

The reaction between BiI 3 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 ][Bi 3 I 12 ] which was characterised by X‐ray crystallography and consists of octahedral [Bi(dmpu) 6 ] 3+ cations and [Bi 3 I 12 ] 3− anions both with 3 symmetry. An analogous reaction between SbI 3 and dmpu afforded orange crystals of what is probably a hydrolysis product, [C 5 NH 6 ] 2 [H(dmpu) 2 ][Sb 2 I 9 ], which was also characterised by X‐ray crystallography and contains a face‐shared bioctahedral [Sb 2 I 9 ] 3− anion with two pyridinium cations and a hydrogen bonded [H(dmpu) 2 ] + cation. [CH 2 C(C 6 H 4 ‐4‐NO 2 )CH 2 NMe 3 ]I and one equivalent of SbI 3 afforded the orange crystalline complex [CH 2 C(C 6 H 4 ‐4‐NO 2 )CH 2 NMe 3 ] 3 [Sb 2 I 9 ] an X‐ray crystallographic study of which revealed a face‐shared bioctahedral [Sb 2 I 9 ] 3− anion similar to that present in [C 5 NH 6 ] 2 [H(dmpu) 2 ][Sb 2 I 9 ]. Four equivalents of BiI 3 and [CH 2 C(C 6 H 4 ‐4‐NO 2 )CH 2 NMe 3 ]I afforded the complex [CH 2 C(C 6 H 4 ‐4‐NO 2 )CH 2 NMe 3 ] 3 [Bi 3 I 12 ], the [Bi 3 I 12 ] 3− anion being essentially identical to that encountered in [Bi(dmpu) 6 ][Bi 3 I 12 ]. [CH 3 (CH 2 ) 2 COS(CH 2 ) 2 NMe 3 ]I and four equivalents of SbI 3 yielded orange crystals of the complex [CH 3 (CH 2 ) 2 COS(CH 2 ) 2 NMe 3 ] 4 [Sb 8 I 28 ] 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).