Potentiometric titration, biomolecular interactions, and docking insights of N-heterocyclic carbene gold(I) complexes derived from the marine betaine 1,3-dimethylimidazolium-4-carboxylate

This study presents three structurally distinct Au(I)-NHC (N-heterocyclic carbene) complexes derived from the marine betaine norzooanemonin (1,3-dimethylimidazolium-4-carboxylate), with a focus on their solution behavior and biological interactions. Given the established link between complex hydrolysis and biological activity, acid-base potentiometric titrations were conducted to determine their equilibrium constants and thermodynamic parameters in aqueous media. Kinetic studies involving 5′-GMP, guanosine, and glutathione provided insight into biomolecular binding preferences. Interactions with calf thymus DNA (CT-DNA) and human serum albumin (HSA) were investigated using UV-vis and fluorescence spectroscopy to elucidate binding modes and affinities. CT-DNA studies evaluated the potential for intercalation versus minor groove binding, while HSA binding site specificity was explored. Molecular docking supported experimental data by modeling interactions with B-form CT-DNA and intercalative DNA structures, as well as HSA subdomains IIA and IIIA. Collectively, the results offer insight into the structural and functional characteristics of the complexes and highlight their potential for biomedical applications.