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Observation of a Cu II 2 (μ‐1,2‐peroxo)/Cu III 2 (μ‐oxo) 2 Equilibrium and its Implications for Copper–Dioxygen Reactivity
Author(s) -
KieberEmmons Matthew T.,
Ginsbach Jake W.,
Wick Patrick K.,
Lucas Heather R.,
Helton Matthew E.,
Lucchese Baldo,
Suzuki Masatatsu,
Zuberbühler Andreas D.,
Karlin Kenneth D.,
Solomon Edward I.
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201402166
Subject(s) - reactivity (psychology) , chemistry , electrophile , nucleophile , adduct , copper , density functional theory , molecule , transition metal , absorption spectroscopy , resonance (particle physics) , photochemistry , medicinal chemistry , inorganic chemistry , computational chemistry , catalysis , organic chemistry , medicine , physics , alternative medicine , pathology , quantum mechanics , particle physics
Synthesis of small‐molecule Cu 2 O 2 adducts has provided insight into the related biological systems and their reactivity patterns including the interconversion of the Cu II 2 (μ‐η 2 :η 2 ‐peroxo) and Cu III 2 (μ‐oxo) 2 isomers. In this study, absorption spectroscopy, kinetics, and resonance Raman data show that the oxygenated product of [(BQPA)Cu I ] + initially yields an “end‐on peroxo” species, that subsequently converts to the thermodynamically more stable “bis‐μ‐oxo” isomer ( K eq =3.2 at −90 °C). Calibration of density functional theory calculations to these experimental data suggest that the electrophilic reactivity previously ascribed to end‐on peroxo species is in fact a result of an accessible bis‐μ‐oxo isomer, an electrophilic Cu 2 O 2 isomer in contrast to the nucleophilic reactivity of binuclear Cu II end‐on peroxo species. This study is the first report of the interconversion of an end‐on peroxo to bis‐μ‐oxo species in transition metal‐dioxygen chemistry.