Synthesis, characterization, and SAMs electroactivity of ruthenium complexes with sulfur containing ligands
- 作者：Jackson R. de Sousa ; Izaura C.N. Dió ; genes ; Má ; rcia L.A. Temperini ; Francisco A.M. Sales ; Solange de O. Pinheiro ; Raimundo N. Costa Filho ; José ; S. de Andrade Jú ; nior ; Í ; caro de S
- 关键词：Sulfur containing ligands ; Ruthenium complexes ; Cyclic voltammetry ; Computational simulation ; SAM ; Cytochrome c
- 刊名：Journal of Organometallic Chemistry
- 出版年：2007
- 期刊代码：64_0022328x
- 类别：ch
- 出版时间：1 August 2007
- 卷：692
- 期：17
- 页码：3691-3699
- 文件大小：577 K
摘要
The vibrational and 1H NMR data hints that the coordination of the 2,2′-dithiodipyridine (2-pySS) ligand to the [Ru(CN)5]3− metal center occurs through the sulfur atom instead of the nitrogen atoms which is usually observed for N-heterocyclic ligands. Electrochemical results show that this coordination mode implies an additional thermodynamic stabilization of the RuII over RuIII oxidation state due to a relative stronger π-back-bonding interaction with the empty low-lying dπ orbitals of the sulfur atom. Computational data reinforce the experimental results showing that the 2-pySS Lewis base centers are located on the sulfur atoms. Ligands containing only sulfur atoms as coordination sites (2,2′-dithiodipyridine N-oxide (2-pySSNO), 1,4-dithiane (1,4-dt), and 2,6-dithiaspiro[3.3]heptane (asp)) were also coordinated to the [Ru(CN)5]3− metal center to undoubtedly correlate the electrochemical results with the ligand coordination atom. Among the synthesized compounds, the [Ru(CN)5(1,4-dt)]3− and [Ru(CN)5(asp)]3− complexes showed to be able to form self-assembled monolayers (SAMs) on gold. These SAMs, which were characterized by SERS (surface-enhanced Raman scattering) spectroscopy, successfully assessed the heterogeneous electron transfer reaction of the cytochrome c metalloprotein in physiological medium.