Chemistry - A European Journal 2017-09-21

Halogen contacts-induced unusual coloring in Bi(III) bromide complex: anion-to-cation charge transfer via Br···Br interactions

Sergey A. Adonin, Igor D. Gorokh, Alexander S. Novikov, Pavel A. Abramov, Maxim N. Sokolov, Vladimir P. Fedin

Index: 10.1002/chem.201703747

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Abstract

A yellow bromobismuthate {(2-BrPy)2H}[BiBr4] (1) transforms into unusually deeply colored cherry-red (2-BrPyH)2[BiBr5] (2). Combination of structural studies and theoretical calculations confirms that appearance of short non-covalent Br···Br interactions (≈ 3.3 Å) in 2 is responsible for the anion-to-cation charge transfer (LP(Brligand) σ*(Br-C)), yielding in dramatic changes in optical behavior. This effect opens the way towards novel halogen bonding-templated halometalate-based hybrid materials with enhanced optical properties.