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Snapshots of a Reversible Metal–Ligand Two-Electron Transfer Step Involving Compounds Related by Multiple Types of Isomerism

✍ Scribed by Cristina Tejel; Laura Asensio; M. Pilar del Río; Bas de Bruin; José A. López; Miguel A. Ciriano


Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
565 KB
Volume
2012
Category
Article
ISSN
1434-1948

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✦ Synopsis


Abstract

An unusual and very fast equilibrium between two isomers, [(cod)Rh^–I^{(bpa – 2H)^0^}Ir^I^(cod)][rlhar2][(cod)Rh^I^{(bpa – 2H)^2–^}Ir^I^(cod)], which simultaneously display multiple types of isomerism: ligand–metal redox (electromerism), linkage, bond‐stretch and ring‐slippage isomerism, has been studied by NMR spectroscopy and DFT calculations. Both isomers have been isolated by making rational use of their thermodynamic parameters (Δ__H__° = +1.93 kcal mol^–1^; Δ__S__° = +7.8 cal mol^–1^ K^–1^), and have been characterized by X‐ray diffraction methods. The equilibrium that involves a two‐electron exchange between a redox noninnocent ligand, which transforms from a deprotonated amido form into an imine, and a metal that is reduced, could elucidate a thus far obscure step in the oxidative dehydrogenation of amines to imines.