Iodine‐Induced Solvothermal Formation of Viologen Iodobismuthates

Abstract

AbstractReactions of BiI3, KI, 4,4′‐bipyridine (4,4′‐bipy) and alcohols (methanol, benzyl alcohol, 2‐propanol or propanol) in the presence of I2 and a small amount of water afforded four iodobismuthate complexes of N,N′‐dialkyl‐4,4′‐bipyridinium (viologen, V2+), [MV][BiI5] (1, MV2+ = N,N′‐dimethyl‐4,4′‐bipyridinium), [BzV]2[Bi2I8(μ‐I)2] (2, BzV2+ = N,N′‐dibenzyl‐4,4′‐bipyridinium), [iPV]2[Bi4I10(μ‐I)4(μ3‐I)2] (3, iPV2+ = N,N′‐diisopropyl‐4,4′‐bipyridinium) and [PV]2[Bi4I8(μ‐I)8] (4, PV2+ = N,N′‐dipropyl‐4,4′‐bipyridinium) under solvothermal conditions. The V2+ dications were formed from iodine‐induced C–O bond cleavage of alcohols followed by alkylation of 4,4′‐bipy. The Bi centre of the [BiI5]2– anion of 1 adopts a square‐pyramidal coordination geometry, whereas the [Bi2I10]4– anion of 2 consists of a dimeric structure comprising two edge‐sharing BiI6 octahedra. The tetranuclear [Bi4I16]4– anion of 3 has an incomplete double cubane structure in which two incomplete [Bi3(μ‐I)2(μ3‐I)2] cubane‐like fragments are fused by sharing two Bi and two μ3‐I atoms, whereas that of 4 contains a bent Bi4 chain in which the [Bi2I10]4– anion of 2 is fused with two BiI6 units through six shared μ‐I atoms. The optical, electrical conductivity and dielectric properties of 1–4 were also investigated.