Insights into non-covalent interactions, molecular and electronic structures of 3-monosubstituted and 3,5-disubstituted 1,2-dithiolylium salts: Crystallographic visualization, Hirshfeld surface analysis and DFT Calculations

Abstract

Compounds based on 3-monosubstituted and 3,5-disubstituted-1,2-dithiolylium salts are subjects of conventional visualization and Hirshfield surface (HS) analyses to investigate the structure and stability-directing effects of functional groups of substituents and counterions in controlling their solid-state behaviour. Both tools show the qualitative and quantitative interplay respectively of the rich network of interactions and short intermolecular contacts that culminate in important packing and geometrically aligned patterns in these compounds and the hierarchies that exist within such interplay. The hierarchies are attributed to the induction of secondary interactions and conformational variations. In addition, quantum chemical calculations of the M06/def2-TZVP model comprising the Minnesota 06 (M06) functional and Ahlrichs/Karlsruhe valence triple-zeta (with) polarization (def2-TZVP) basis set are further used to explore the structure-property relationship in these compounds. The optimization of their molecular geometries showed reasonable correlation with their respective experimental structures. Frontier molecular orbital (FMO) and natural bond orbital (NBO) investigations on the 3-D structures are used to identify intra- and intermolecular charge transfer potentials via cation→anion (donor/acceptor) interactions and their significant roles in stabilizing molecular moieties.