Experimental and Theoretical Investigations of the Existence of CuII, CuIII, and CuIV in Copper Corrolato Complexes. Issue 46 (25th September 2015)

• Record Type: Journal Article
• Authors: Sinha, Woormileela; Sommer, Michael G.; Deibel, Naina; Ehret, Fabian; Bauer, Matthias; Sarkar, Biprajit; Kar, Sanjib
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 46(2015)
• Page Start: 13769
• Page End: 13774
• Publication Date: 2015-09-25
• Subjects: copper corroles -- EPR spectroscopy -- higher oxidation states -- spectroelectrochemistry -- XANES measurements; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201507330
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The most common oxidation states of copper in stable complexes are +I and +II. Cu III complexes are often considered as intermediates in biological and homogeneous catalysis. More recently, Cu IV species have been postulated as possible intermediates in oxidation catalysis. Despite the importance of these higher oxidation states of copper, spectroscopic data for these oxidation states remain scarce, with such information on Cu IV complexes being non‐existent. We herein present the synthesis and characterization of three copper corrolato complexes. A combination of electrochemistry, UV/Vis/NIR/EPR spectroelectrochemistry, XANES measurements, and DFT calculations points to existence of three distinct redox states in these molecules for which the oxidation states +II, +III, and +IV can be invoked for the copper centers. The present results thus represent the first spectroscopic and theoretical investigation of a Cu IV species, and describe a redox series where Cu II, Cu III, and Cu IV are discussed within the same molecular platform. Abstract : Fly high : Electrochemical, UV/Vis/NIR/EPR spectroelectrochemical, and XANES measurements as well as DFT calculations point to the existence of three distinct redox states in the title compounds as oxidation states of +II, +III, and +IV can be invoked for the copper centers. These results thus represent the first spectroscopic and theoretical investigation of a Cu IV species.