An insight into non-covalent interactions in the tetraphenylarsonium dithiophosphates: Synthesis, DFT and Hirshfeld Surface Analysis

Abstract Three tetraphenylarsonium dithiophosphate salts [Ph4As]+[S2P(OAr)2]−, where Ar = 2,4-(CH3)2C6H3 (1), 3,5-(CH3)2C6H3 (2), {4-(CH3)3C}C6H4 (3), were crystallized in the monoclinic space group P21 (1), triclinic space group P¯1 (2) and monoclinic space group P21/c (3), respectively. These salts are stabilized by various non-covalent interactions resulting in the extension of their molecular structure along different axis. The cationic and anionic species are interconnected by various C—H•••X, C—H•••π (X= O, S) interactions leading the molecules as one-dimensional and two-dimensional supramolecular structures. A thorough Hirshfeld surface analysis elegantly quantifies the various non-covalent interactions present within the molecules. This analysis reveals that the main contributions in all the three salts are because of H…H and C…H/H…C interactions that represent 82.1%, 82.9% and 84.1% of the total contribution to the Hirshfeld surface for 1, 2 and 3, respectively. Further, the coordinates were optimized by DFT calculations with B3LYP hybrid functional along with LANL2DZ basis set. Experimental values of bond lengths and bond angles are in good agreement with the optimized structural parameters. HOMO-LUMO of the molecules were calculated using corresponding methods with the same basis set. Other computational data pertaining to chemical reactivity have indicated potential sites for nucleophilic and eletrophilic attack in the molecules.