Interactions of neutral and cationic transition metals with the redox system of hydroquinone and quione: Theoretical characterization of the binding topologies, and implications for the formation of nanomaterials

Abstract

To understand the self-assembly process of the transition metal (TM) nanoclusters and nanowires self-synthesized by hydroquinone (HQ) and calix[4]hydroquinone (CHQ) by electrochemical redox processes, we have investigated the binding sites of HQ for the transition-metal cations TMn+=Ag+, Au+, Pd2+, Pt2+, and Hg2+ and those of quinone (Q) for the reduced neutral metals TM0, using ab initio calculations. For comparison, TM0-HQ and TMn+-Q interactions, as well as the cases for Na+ and Cu+ (which do not take part in self-synthesis by CHQ) are also included. In general, TM-ligand coordination is controlled by symmetry constraints imposed on the respective orbital interactions. Calculations predict that, due to synergetic interactions, silver and gold are very efficient metals for one-dimensional (1D) nanowire formation in the self-assembly process, platinum and mercury favor both nanowire/nanorod and thin film formation, while palladium favors two-dimensional (2D) thin film formation.