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Y. Prokudina, E. Davydova, A. Virovets, B. Stöger, E. Peresypkina, A. Pomogaeva, A. Timoshkin:
"Structures and Chemical Bonding in Antimony(III) Bromide Complexes with Pyridine";
Chemistry - A European Journal, 26 (2020), 16338 - 16348.

Weakly or "partially" bonded molecules are an important link between the chemical and van der Waals interactions. Molecular structures of six new SbBr3-Py complexes in the solid state have been determined by single-crystal X-ray diffraction analysis. In all complexes all Sb atoms adopt a pseudo-octahedral coordination geometry which is completed by additional Sb···Br contacts shorter than the sum of the van der Waals radii, with Br---Sb···Br angles close to 180°. To reveal the nature of Sb-Br and Sb-N interactions, the DFT calculations were performed followed by the analysis of the electrostatic potentials, the orbital interactions and the topological analysis. Based on Natural Bond Orbital (NBO) analysis, the Sb-Br interactions range from the covalent bonds to the pnictogen bonds. A simple structural parameter, non-covalence criterion (NCC) is defined as a ratio of the atom-atom distance to the linear combination of sums of covalent and van der Waals radii. NCC correlates with E(2) values for Sb---N, Sb---Cl and Sb---Br bonds, and appears to be useful criterion for a preliminary evaluation of the bonding situation.

antimony(III) complexes, DFT computations, electronic structure, pnictogen bonds, structural analysis

http://dx.doi.org/10.1002/chem.202002261