A Ligand-Bridged Heterotetranuclear (Fe2Cu2) Redox System with Fc/Fc(+) and Radical Ion Intermediates

作者：Jana Rajkumar; Lissner Falk; Schwederski Brigitte; Fiedler Jan; Kaim Wolfgang^*

来源：Organometallics, 2013, 32(20): 5879-5886.

DOI：10.1021/om400466u

The redox pair [(mu-abcp){Cu(dppf)}(2)](2+/+) (abcp = 2,2%26apos;-azobis(5-chloropyrimidine) and dppf = 1,1%26apos;-bis(diphenylphosphino)ferrocene) has been structurally characterized to reveal the lengthening of the NN and shortening of the CNazo bonds on reduction, each by about 0.04 angstrom. These and other charge forms, [(mu-abcp){Cu(dppf)}(2)](n+) (n = 0, 3+, 4+), have been investigated spectroelectrochemically (UV-vis-near-IR, EPR) to reveal an abcp-based second reduction and a stepwise ferrocene-centered oxidation of the 2+ precursor. In contrast to the small but detectable comproportionation constant of K-c = 17 for the Fc/Fc(+) mixed-valence (3+) charge state, the monocationic radical complex exhibits a very large K-c value of 10(16).

• 出版日期2013-10-28