Preparation, spectroscopy, and electrochemistry of cyano-bridged bis(oxo-centered-hexa(μ-acetato)-triruthenium) complexes

Hua Xin Zhang, Yoichi Sasaki, Masaaki Abe, Yi Zhang, Shen Ye, Masatoshi Osawa

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Preparation, characterization, and properties of a cyano bridged complex containing the Ru33-O) cores, [{Ru33-O) (μ-CH3COO)6(py)2}2(μ-CN)](PF6) ([1]PF6) (py = pyridine), are reported and compared with the properties of [{Ru33-O)(μ-CH3COO)6(py)2}(μ-CN){Ru33-O)(μ-CH3COO)6(py)(CO)}] (2). The cyclic voltammogram of [1]+ in 0.1 M (n-Bu)4NPF6-CH2Cl2 solution with an Ag/AgCl reference electrode showed a series of redox waves assigned to the processes Ru3II,II,III/Ru3II,III,III (-1.70 V, -1.52 V), Ru3II,III,III/Ru3III,III,III (-0.37 V, -0.19 V), Ru3III,III,III/Ru3III,III,IV (+1.08 V), and Ru3III,III,IV/Ru3III,IV,IV (+2.03 V). Upon bridge formation the redox waves of the C-bonded Ru3 moiety of [1]+ stay at the similar potential region to those of Ru33-O)(μ-CH3COO)6(py)2(CN) (3) with a unidentate CN-, so that the enhancement of the π-back donation does not operate, indicating that the Ru3O core is not a good π-donor. Complex 2 showed five redox waves for the processes Ru3II,II,III/Ru3II,III,III (-1.15 V), Ru3II,III,III/Ru3III,III,III (-0.21 V, +0.55 V), and Ru3III,III,III/Ru3III,III,IV (+1.05 V, +1.35 V). The redox potential (-1.15 V) of the Ru3II,II,III/Ru3II,III,III process of the Ru3(py) (CO) unit in 2 showed a negative shift in comparison to that (-0.84 V) of [Ru3II,III,III3-O) (μ-CH3COO)6(py)2(CO)]. The infrared spectroelectrochemistry of [1]+ and 2 in 0.1 M n-Bu4NPF6-CH2Cl2 solutions revealed that the frequencies of the stretching vibration ν(CN) of the cyanide increased with the increase in the isovalent oxidation states of [1]+ but those in the Ru3O-based mixed-valence states, Ru3II,III,III-Ru3III,III,III, and Ru3III,III,III-Ru3III,III,IV, were significantly smaller, which was possibly due to the effective electronic coupling through the CN- bridge between the two Ru3 units with different oxidation states. In contrast, such coupling was not observed for 2 that has two Ru3 units with significantly different ligand environment.

Original languageEnglish
Pages (from-to)29-36
Number of pages8
JournalJournal of Organometallic Chemistry
Volume797
DOIs
Publication statusPublished - 2015 Aug 11

Keywords

  • Cyanide ligand
  • Infrared spectroelectrochemistry
  • Oxo-centered triruthenium clusters
  • Redox property

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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