Title
Chemical and Redox Noninnocence of Pentane-2,4-dione Bis(S-methylisothiosemicarbazone) in Cobalt Complexes and Their Application in Wacker-Type Oxidation
Author
Miljan N. M. Milunovic
Ulrich Knof
Novartis Pharma AG
... show all
Abstract
Cobalt complexes with multiproton- and multielectron-responsive ligands are of interest for challenging catalytic transformations. The chemical and redox noninnocence of pentane-2,4-dione bis(S-methylisothiosemicarbazone) (PBIT) in a series of cobalt complexes has been studied by a range of methods, including spectroscopy [UV–vis, NMR, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS)], cyclic voltammetry, X-ray diffraction, and density functional theory (DFT) calculations. Two complexes [CoIII(H2LSMe)I]I and [CoIII(LSMe)I2] were found to act as precatalysts in a Wacker-type oxidation of olefins using phenylsilane, the role of which was elucidated through isotopic labeling. Insights into the mechanism of the catalytic transformation as well as the substrate scope of this selective reaction are described, and the essential role of phenylsilane and the noninnocence of PBIT are disclosed. Among the several relevant species characterized was an unprecedented Co(III) complex with a dianionic diradical PBIT ligand ([CoIII(LSMe••)I]).
Keywords
cobaltpentane-2,4-dione bis(S-methylisothiosemicarbazone)noninnocenceredoxmultiprotonketoneolefinoxidation
Object type
Language
English [eng]
Persistent identifier
Appeared in
Title
JACS Au
Volume
4
Issue
3
ISSN
2691-3704
Issued
2024
From page
1166
To page
1183
Publication
American Chemical Society (ACS)
Version type
Date issued
2024
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