Synthesis and crystal structure of the adduct between 2-pyridyl-selenyl chloride and isobutyro-nitrile.

The reaction between 2-pyridyl-selenenyl chloride and isobutyro-nitrile results in the formation of the corresponding cationic pyridinium-fused 1,2,4-seleno-diazole, namely, 3-(propan-2-yl)-1,2,4-[1,2,4]selena-diazolo[4,5-a]pyridin-4-ylium chloride, C(9)H(11)N(2)Se(+)·Cl(-), in high yield (89%). The structure of the compound, established by means of single-crystal X-ray analysis at 100†K, has monoclinic (P2(1)/c) symmetry and revealed the presence of bifurcated chalcogen-hydrogen bonding Se⋯Cl(-)⋯H-Cl, and these non-covalent contacts were analysed by DFT calculations followed by a topological analysis of the electron-density distribution (ωB97XD/6-311++G** level of theory).