Reexamining Oxidation States during the Synthesis of 2‑Rhodaoxetanes from Olefins

• Published in: Inorganic chemistry Vol. 55; no. 1; pp. 13 - 15
• Main Authors: Desnoyer, Addison N, Behyan, Shirin, Patrick, Brian O, Dauth, Alexander, Love, Jennifer A, Kennepohl, Pierre
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.01.2016
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.5b02703

Herein, we report experimental, spectroscopic, and computational data that indicate that a rhodium ethylene complex, formally described as rhodium­(I) and which forms a 2-rhoda­(III) oxetane following reaction with H2O2, is more accurately described as a rhodium­(III) metallacyclopropane. X-ray absorption spectroscopy clearly demonstrates a change in the oxidation state at rhodium following ligand coordination with tris­(2-pyridylmethyl)­amine. Both NMR and density functional theory studies suggest a high energy barrier to rotation of the coordinated ethylene, which is attributed to large geometric and electronic reorganization resulting from the loss of π-back-bonding. These results imply that the role of H2O2 in the formation of 2-rhoda­(III) oxetanes is to oxidize the C2H4 fragment rather than the metal center, as has been previously suggested.