Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
PINHEIRO, Solange de Oliveira et al. Tetraammine ruthenate complexes: cationic SAMs for cytochrome c recognition. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.8, pp. 1594-1599. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532006000800016.
The redox process of the cyt c metalloprotein was assessed by the cationic SAMs formed with [Ru(CNPy)(NH3)4(1,4-dt)]2+ and [Ru(CNPy)(NH3)4(pyS)]2+ complexes on gold, where CNPy = 4-cyanopyridine, pyS = 4-mercaptopyridine and 1,4-dt = dithiane. The observed cyt c redox potentials are indicative of the native protein form. The voltammograms, however, were observed to be affected by the conformation of the modifiers, determined by SERS spectroscopy. The [Ru(CNPy)(NH3)4(pyS)]2+ complex, which exhibits trans conformation on the surface, presented a well-defined voltammogram. On the other hand, the gauche conformation of the [Ru(CNPy)(NH3)4(1,4-dt)]2+ SAM seems to make the assessment of the cyt c hET reaction difficult. The reductive desorption potentials, at -0.52 and -0.64 V vs Ag|AgCl|Cl- for the [Ru(CNPy)(NH3)4(1,4-dt)]2+ and [Ru(CNPy)(NH3)4(pyS)]2+ SAMs, respectively, are indicative of the bonding mode with the surface and the p withdrawing capability of the CNpy ligand.
Keywords : self-assembled monolayers; cytochrome c; tetraamineruthenate complexes; sulfur ligands.