CONICET | Buscador de Institutos y Recursos Humanos

Organic molecules can be used as electronic components in metal-metal junctions or as molecular wires to connect with electroactive species in solutions. The simplest molecular junctions are thiols and dithiols where the thiol molecules are bonded to a metal surface by a strong covalent bond. The fabrication of more complex molecular structures consisting of electron transport carriers bonded to the thiols molecules by weak interactions or covalent bonds have been extensively studied in recent years. Coordination chemistry also open the possibility of immobilize metallic complexes to metals by interaction of the metallic centers with specific atoms of the terminal groups of the SAMs. In contrast to non specific interactions coordination chemistry allows to control the spatial configuration of the complex supramolecular structure. In this communication we present the results of the study of the immobilization of a copper acetate complex on N, COO-, S donors at the terminal group of different aliphatic and aromatic thiols to understand the influence of the terminal-group-metal ion contact in the charge transfer process and the capability of charge transfer process to occur. The voltammetric data on the complex/functionalized SAM Au interface shows the typical redox couple corresponding to Cu(II)/ Cu(I) species indicating that the Cu ionic species are immobilized in the thiol SAMs, and that at least some of them, are electrochemically active, i.e. they are able to participate in the charge transfer process with the Au electrode through the SAMs. XPS spectra of the different supramolecular structures allow discussing the role of chain length and chemical nature of the terminal anchor in the efficiency of charge transfer.