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Dioxygen Activation by a Macrocyclic Copper Complex Leads to a Cu 2 O 2 Core with Unexpected Structure and Reactivity
Author(s) -
GarciaBosch Isaac,
Cowley Ryan E.,
Díaz Daniel E.,
Siegler Maxime A.,
Nam Wonwoo,
Solomon Edward I.,
Karlin Kenneth D.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201600551
Subject(s) - reactivity (psychology) , protonation , chemistry , ligand (biochemistry) , copper , stereochemistry , kinetics , crystallography , medicinal chemistry , organic chemistry , ion , receptor , medicine , biochemistry , physics , alternative medicine , pathology , quantum mechanics
We report the Cu I /O 2 chemistry of complexes derived from the macrocylic ligands 14‐TMC (1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane) and 12‐TMC (1,4,7,10‐tetramethyl‐1,4,7,10‐tetraazacyclododecane). While [(14‐TMC)Cu I ] + is unreactive towards dioxygen, the smaller analog [(12‐TMC)Cu I (CH 3 CN)] + reacts with O 2 to give a side‐on bound peroxo‐dicopper(II) species ( S P), confirmed by spectroscopic and computational methods. Intriguingly, 12‐TMC as a N4 donor ligand generates S P species, thus in contrast with the previous observation that such species are generated by N2 and N3 ligands. In addition, the reactivity of this macrocyclic side‐on peroxo‐dicopper(II) differs from typical S P species, because it reacts only with acid to release H 2 O 2 , in contrast with the classic reactivity of Cu 2 O 2 cores. Kinetics and computations are consistent with a protonation mechanism whereby the TMC acts as a hemilabile ligand and shuttles H + to an isomerized peroxo core.