Synthesis and redox behavior of biferrocenyl-functionalized ruthenium(II) terpyridine gold clusters.
Spectroscopic and electrochemical characterizations of ferrocene- and biferrocene-functionalized terpyridine octanethiolate monolayer-protected clusters were investigated and reported. The electrochemical measurements of Ru2+ coordinated with 4'-ferrocenyl-2,2':6',2' '-terpyridine and 4'-biferrocenyl-2,2':6',2' '-terpyridine complexes were dominated by the Ru2+/Ru3+ redox couple (E(1/2) at approximately 1.3 V), Fe(2+)/Fe(3+) redox couples (E(1/2) from approximately 0.6 to approximately 0.9 V), and terpy/terpy-/terpy2- redox couples (E(1/)(2) at ca. -1.2 and ca. -1.4 V). The substantial appreciable variations detected in the Ru2+/Ru3+ and Fe2+/Fe3+ oxidation potentials indicate that there is an interaction between the Ru2+ and Fe2+ metal centers. The coordination of the Ru2+ metal center with 4'-ferrocenyl-2,2':6',2' '-terpyridine and 4'-biferrocenyl-2,2':6',2' '-terpyridine leads to an intense 1[(d(pi)Fe)6] --> 1[d(pi)Fe)5(pi*terpyRu)1] transition in the visible region. The 1[(d(pi)Fe)6] -->1[d(pi)Fe)5(pi*terpyRu)1] transition observed at approximately 510 nm revealed that there was a qualitative electronic coupling between metal centers. The coordination of the Ru2+ transition metal center lowers the energy of the pi*terpy orbitals, causing this transition.
Department of Chemistry, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Teng-Yuan
TY
Dong
Hao-Wei
HW
Shih
Ling-Shao
LS
Chang
D004563:Electrochemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D000075163:Metallocenes; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010316:Particle Size; D011725:Pyridines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013499:Surface Properties
C509669:4'-ferrocenyl-2,2':6',2' '-terpyridine; D005296:Ferrous Compounds; D000075163:Metallocenes; D009942:Organometallic Compounds; D011725:Pyridines; D006046:Gold; D012428:Ruthenium; C013278:2,2',2''-terpyridine; C004998:ferrocene