Unexpected Polymorphism in Bromoantimonate(III) Complexes and Its Effect on Optical Properties
Andrey N. Usoltsev, Taisiya S. Sukhikh, Alexander S. Novikov, Vladimir R. Shayapov, Denis P. Pishchur, Ilya V. Korolkov, I. F. Sakhapov, Vladimir P. Fedin, Maxim N. Sokolov⧫, Sergey A. Adonin
Abstract
Reactions of [SbBr6]3– containing HBr solutions with bromide salts of 1,1′-(1,2-ethanediyl)bis(pyridine) (PyC22+) or 1,1′-(1,2-ethanediyl)bis(3,5-dimethylpyridine) (3,5-MePyC22+) initially result in the formation of the deep orange complexes Cat[SbBr5] (1 and 2), featuring unusual Sb···Br interactions in the solid state. In the mother liquor, 1 transforms into discrete binuclear (C2Py)2[Sb2Br10], which demonstrates polymorphism (triclinic 3 and monoclinic 4), while 2 transforms into polymeric (3,5-MePy){[SbBr4]} (5). DFT calculations reveal that the system of noncovalent Sb···Br contacts may be responsible for the appearance of the observed optical properties (unusual deep orange coloring).