Qualitative and quantitative contributions of intermolecular interactions of dinuclear Ag complexes of sulfathiazole and sulfadiazine: X-ray crystallographic, Hirshfeld surface analysis, DFT studies and biological activities

Abstract

Two dinuclear Ag complexes of N-heterocycle ‘sulfa’ derivatives: sulfathiazole (STZ) and sulfadiazine (SDZ) have been synthesized and characterized. Crystal structures of both the Ag-STZ and Ag-SDZ complexes have been determined by single crystal X-ray diffraction technique. In both the dinuclear Ag complex, two Ag atoms bridged together forming argentophilic interaction with Ag – Ag separation distance of 2.846 (4) Å in Ag-STZ and 2.828 (3) Å in Ag-SDZ respectively. In Ag-STZ complex, the coordination geometry surrounding silver atoms (Ag) is tridentate and tetradentate whereas, in Ag-SDZ complex, the geometry surrounding Ag is tetradentate and pentadentate respectively while coordinating to the respective bidentate ligand. Qualitative and quantitative contributions of each intermolecular interaction as established by X-ray data are investigated using Hirshfeld surface and energy framework analysis. Atomic charge explored by Mulliken charge distributions and natural bond orbital (NBO) analysis confirmed the nature and type of intermolecular interactions as established by X-ray data. In vitro cytotoxicity of the Ag complexes and those of the free ligands have been carried out against brine shrimp.