Dioxygen Activation by Siloxide Complexes of Chromium(II) and Chromium(IV)1. Issue 47 (26th September 2014)

• Record Type: Journal Article
• Authors: Schax, Fabian; Bill, Eckhard; Herwig, Christian; Limberg, Christian
• Is Part Of: Angewandte Chemie international edition. Volume 53:Issue 47(2014)
• Page Start: 12741
• Page End: 12745
• Publication Date: 2014-09-26
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201406313
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The reaction of a tripodal trisilanol with <italic>n</italic>‐butyllithium and CrCl₂ results in a dinuclear Cr^II complex (<bold>1</bold>), which is capable of cleaving O₂ to yield in a unique complex (<bold>2</bold>) with an asymmetric diamond core composed of two Cr^IVO units. Magnetic susceptibility data reveal significant exchange coupling of Cr^II (<italic>S</italic>=2) in <bold>1</bold> and large zero‐field splitting for Cr^IV (<italic>S</italic>=1) in <bold>2</bold> owing to strong spin–orbit coupling of the ground state. The Cr^IVO compound can also be generated using PhIO, and evidence was gathered that although it is the stable product isolated after excessive O₂ treatment, it further activates O₂ to yield an intermediate species that oxidizes THF or Me‐THF. By extensive ¹⁸O labeling studies we were able to show, that in the course of this process ¹⁸O₂ exchanges its label with siloxide O atoms of the ligand via terminal oxido ligands.</p> </abstract>