Selenium(IV) Polybromide Complexes: Structural Diversity Driven by Halogen and Chalcogen Bonding.

Reactions between bromoselenate(IV)-containing solutions, dibromine and salts of pyridinium-family organic cations resulted in structurally diverse, bromine-rich polybromine-bromoselenates(IV): (4-MePyH) 5 [Se 2 Br 9 ][SeBr 6 ](Br 3 ) 2 ( 1 ), (2-MePyH) 2 {[SeBr 6 ](Br 2 )} ( 2 ), (PyH) 2 {[SeBr 5 ]Br(Br 2 ) 2 } ( 3 ), (1-MePy) 2 {[SeBr 6 ](Br 2 )} ( 4 ). The compounds feature halogen and (in the case of 3 ) chalcogen bonding in solid state, resulting in formation of supramolecular architectures of different dimensionality. DFT calculations allowed estimation of the energies of non-covalent interactions in 1 - 4 ; additionally, characterization by Raman spectroscopy was performed.