Tetranuclear Ag(I) and Au(I) nano-sized [L₂(R)₈→M₄]⁴⁺ (M = Ag(I) and Au(I); R = C₂H₅, CH₃, H, F, Cl, Br, Ph and SiH₃) complexes: Nature and cooperativity of metal-ligand bonds

Abstract

NHC ligands are able to stabilize different metals in different oxidation states and coordination geometries, making them interesting candidates for the synthesis of potent metal-based anti-cancer agents. This study explores the bonding characteristics and nature of cooperativity in tetranuclear cationic complexes of Ag(I) and Au(I), formulated as [L₂(R)₈→M₄]⁴⁺ (M = Ag(I) and Au(I); R = C₂H₅, CH₃, H, F, Cl, Br, Ph and SiH₃), with potential antibacterial and anticancer properties using DFT calculations at the PBE-D3-B3LYP/def2-SVP//PBE-D3/def2-TZVP level. Bond cooperativity, evaluated through interaction energies, and the resulting data indicated that there is an anti-cooperativity behavior among the metal–ligand interactions. EDA results confirm that electrostatic contributions are found to be dominant, suggesting that the CNHC→M bonds in these complexes are primarily electrostatic in nature.