Synthesis, structural characterization, Hirshfeld surface analysis and QTAIM analysis of 3-(4-cyanothiophen-3-yl)-[1,2,4]selenadiazolo[4,5-a]pyridin-4-ium chloride

The title compound, C11H6N3SSe+ Cl- , produced by the reaction between 3,4- dicyanothiophene and 2-pyridylselenyl chloride was isolated as a salt that crystallizes in the triclinic space group P1. Notable features include strong chalcogen interactions (Se Cl and Se S), as revealed through Hirshfeld surface analysis, which also highlights significant contributions from N H/ H N, C H/H C and H H contacts in the crystal packing. Supramolecular interactions were further analysed using density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) at the ωB97XD/6-311++G**level of theory. © 2025 International Union of Crystallography. All rights reserved.