trans-[Ru(NH3)4(pyS)X] complexes: syntheses, characterization and self-assembled monolayer on gold

In Inorganic Chemistry, the term Coordination Compounds includes species formed by a transition metal atom or ion and one or more ligands (atoms, ions or molecules) that formally donate electron density to the metal species. Nowadays coordination compounds are used in diverse areas such as materials (catalysis), photochemistry, bioinorganic (Metallodrugs), inorganic physics (molecular wires) and electrochemistry (modified electrodes and biosensors). In this work, a series of complexes of the type trans-[Ru(NH3)4(pyS)X](PF6)2 , where pyS = mercaptopyridine and X = bpa (1,2-bis(4-pyridyl)ethane), bpe (1,2-bis(4-pyridyl)ethylene, py (pyridine), or 4,4´-bpy (4,4´-dipyridyl) (see Figure 1), were synthetized and characterized using conventional vibrational and electronic spectroscopic and electrochemical techniques. Furthermore, density functional theory (DFT) calculations were performed to help with the interpretation of experimental results. These complexes contain the ligand pyS, which allow the spontaneous adsorption (self-assembled) of such compounds on gold surfaces in consequence of the strong Au-S interaction.1-2 Surface plasmon resonance (SPR) was used to monitoring the formation of self-assembled monolayers (SAM) of the complexes on gold and to calculate the amount of adsorbed species. As a perspective, it is intended to evaluate the effect of the ligand X on the strength of the Au-SR bonding.