Coupling between 2-pyridyl­selenyl chloride and phenyl­seleno­cyanate: synthesis, crystal structure and non-covalent inter­actions

The structure of a new seleno­diazo­lium salt derived from the reaction between 2-pyridyl­selenyl chloride and phenyl­seleno­cyanate is described. Halogen–hydrogen, chalcogen–chalcogen, chalcogen–hydrogen and chalcogen–halogen inter­actions are present in the structure.

A new pyridine-fused seleno­diazo­lium salt, 3-(phenyl­selan­yl)[1,2,4]selena­diazolo[4,5-a]pyridin-4-ylium chloride di­chloro­methane 0.352-solvate, C₁₂H₉N₂Se₂⁺·Cl⁻·0.352CH₂Cl₂, was obtained from the reaction between 2-pyridyl­selenenyl chloride and phenyl­seleno­cyanate. Single-crystal structural analysis revealed the presence of C—H⋯N, C—H⋯Cl⁻, C—H⋯Se hydrogen bonds as well as chalcogen–chalcogen (Se⋯Se) and chalcogen–halogen (Se⋯Cl⁻) inter­actions. Non-covalent inter­actions were explored by DFT calculations followed by topological analysis of the electron density distribution (QTAIM analysis). The structure consists of pairs of seleno­diazo­lium moieties arranged in a head-to-tail fashion surrounding disordered di­chloro­methane mol­ecules. The assemblies are connected by C—H⋯Cl⁻ and C—H⋯N hydrogen bonds, forming layers, which stack along the c-axis direction connected by bifurcated Se⋯Cl⁻⋯H—C inter­actions.