Effect of potential difference between the central and terminal metals on the electron communication in an Fe–Ru–Fe cyanidometal-bridged mixed valence system

Abstract

To investigate effect of potential difference between the central and terminal metals on the electron communication in trinuclear mixed valence system, a series of trimetallic cyanidometal-bridged compounds with [CpMexFe-NC-Ru-CN-FeCpMex]n+, Nn+...

MMCT energy change in cyanidometal-bridged trinuclear complexes by changing the ligand electron donating ability

“…That is, the electron communication (Ru II → Fe III ) becomes weaker as the methyl substituent increases. Furthermore, compared with our previously reported similar trinuclear cyanidometal-bridged Fe–Ru–Fe compounds in which the ligand on the central Ru is 4-dimethylaminopyridine, 38 both the Fe II → Fe III MMCT energy of the N 3+ and Ru II → Fe III MMCT energy of N 4+ increase, which is due to the weaker electron-donating ability of 4-isopropylpyridine than 4-dimethylaminopyridine. From Table 4, it can be seen that H ab decreases with the increase of methyl substituents, suggesting that 1 4+ to 5 4+ becomes more localized.…”

“…Therefore, it can be concluded from the results of cyclic voltammograms that the potential difference Δ E 2 of compound 1 2+ –5 2+ becomes larger with increasing electron-donating ability, while Δ E 1 becomes smaller. Compared with the potentials of similar trinuclear cyanidometal-bridged Fe–Ru–Fe compounds previously reported by our group, 38 the potentials of the compounds 1 2+ –5 2+ increase due to the weaker electron-donating ability of 4-isopropylpyridine than that of 4-dimethylaminopyridine.…”

“…7,30,31 The introduction of electron-donating or -withdrawing substituents in the redox centers to adjust the energy levels of terminal metal centers is necessary to facilitate the study of electron transfer processes of MV compounds. 32 Cyanidometal-bridged MV compounds play an important role in the study of MMCT due to their good electron transfer coordination ability. To date, many cyanidometal-bridged MV compounds have been synthesized for the study of MMCT and other properties.…”

Synthesis and structural and spectroscopic properties of a cyanido-bridged mixed-valence compound [Fe–NC–Ru–CN–Fe]

“…According to the above two equations, the spectral parameters obtained are α = 0.0145 and H ab = 1589 cm −1 for 3 . Chemists have synthesized many similar compounds, such as trans -[Cp(dppe)Fe III (NC)Ru II (dmap) 4 (CN)Fe III (dppe)Cp][PF 6 ] 4 , 13 trans -[Cp(dppe)Fe III (NC)Ru II ( t Bu py) 4 (CN)Fe III (dppe)Cp][PF 6 ] 4 , 17 trans -[Cp(dppe)Fe III (NC)Ru II (bpy) 2 (CN)Fe III (dppe)Cp][PF 6 ] 4 26 and trans -[Cp(dppe)Fe III (NC)Ru II (phen) 2 (CN)Fe III (dppe)Cp][PF 6 ] 4 27 (phen = 1,10-phenanthroline, dmap = 4-dimethylaminopyridine). All of these compounds have been investigated as class II mixed-valent compounds.…”

“…11 Compared with other bridging fragments, cyanide-bridges are a good candidate group for MV compounds, and the exploration of their chemistry has revealed clusters of different nuclearities and geometries, so cyanido-bridged MV compounds hold a significant place as important models for understanding the electron transfer in nature. 12,13…”