Iodine‐Induced Solvothermal Formation of Viologen Iodobismuthates

Reactions of BiI 3 , KI, 4,4′‐bipyridine (4,4′‐bipy) and alcohols (methanol, benzyl alcohol, 2‐propanol or propanol) in the presence of I 2 and a small amount of water afforded four iodobismuthate complexes of N , N′ ‐dialkyl‐4,4′‐bipyridinium (viologen, V 2+ ), [MV][BiI 5 ] ( 1 , MV 2+ = N , N′ ‐dimethyl‐4,4′‐bipyridinium), [BzV] 2 [Bi 2 I 8 (μ‐I) 2 ] ( 2 , BzV 2+ = N , N′ ‐dibenzyl‐4,4′‐bipyridinium), [iPV] 2 [Bi 4 I 10 (μ‐I) 4 (μ 3 ‐I) 2 ] ( 3 , iPV 2+ = N , N′ ‐diisopropyl‐4,4′‐bipyridinium) and [PV] 2 [Bi 4 I 8 (μ‐I) 8 ] ( 4 , PV 2+ = N , N′ ‐dipropyl‐4,4′‐bipyridinium) under solvothermal conditions. The V 2+ dications were formed from iodine‐induced C–O bond cleavage of alcohols followed by alkylation of 4,4′‐bipy. The Bi centre of the [BiI 5 ] 2– anion of 1 adopts a square‐pyramidal coordination geometry, whereas the [Bi 2 I 10 ] 4– anion of 2 consists of a dimeric structure comprising two edge‐sharing BiI 6 octahedra. The tetranuclear [Bi 4 I 16 ] 4– anion of 3 has an incomplete double cubane structure in which two incomplete [Bi 3 (μ‐I) 2 (μ 3 ‐I) 2 ] cubane‐like fragments are fused by sharing two Bi and two μ 3 ‐I atoms, whereas that of 4 contains a bent Bi 4 chain in which the [Bi 2 I 10 ] 4– anion of 2 is fused with two BiI 6 units through six shared μ‐I atoms. The optical, electrical conductivity and dielectric properties of 1 – 4 were also investigated.