Bromobismuthates of 1,1'-(1,N-Alkanediyl)bis(picolines): Synthesis, Thermal Stability, Crystal Structures, and Optical Properties

Hybrid bromobismuthates of N-alkylated derivatives of 2- and 3-methylpyridine, (C15H20N2)2Bi2Br10 (I), (C17H24N2)2Bi2Br10 (II), (C18H26N2)3(Bi2Br9)2 (III), (C14H18N2)(H3O)BiBr6 ∙ 2H2O (IV), (C14H18N2)2BiBr6IBr2 (V), (C16H22N2)3(Bi2Br9)2 (VI), and (C18H26N2)3(Bi2Br9)2 (VII), are synthesized in concentrated HBr and characterized by physicochemical methods. The structures of complexes I–VII are studied by X-ray structure analysis (CIF files CCDC nos. 1946844–1946850). Complexes I and II contain anions [Bi2Br10]4–. Anions [Bi2Br9]3– are found in the structures of compounds III, VI, and VII. Bis(3-methyl-1-pyridino)ethane bromobismuthate IV contains cations H3O+ and anions [BiBr6]3– and, unlike other bromobismuthates, decomposes at low temperatures. In presence of HI vapors, double bromobismuthate V containing the [BiBr6]3– and IBr2– anions crystallizes along with compound IV.