TY - JOUR
T1 - Dioxygen Activation by a Macrocyclic Copper Complex Leads to a Cu2O2 Core with Unexpected Structure and Reactivity
AU - Garcia-Bosch, Isaac
AU - Cowley, Ryan E.
AU - Díaz, Daniel E.
AU - Siegler, Maxime A.
AU - Nam, Wonwoo
AU - Solomon, Edward I.
AU - Karlin, Kenneth D.
N1 - Funding Information:
This research was supported by the U.S. NIH (GM28962 to K.D.K., DK31450 to E.I.S., NRSA postdoctoral fellowship F32 GM105288 to R.E.C.) and by the NRF of Korea through CRI (NRF 2012R1A3A2048842) and GRL (NRF 2010 00353) (to W.N.). I.G. B. thanks the E.C. for a Marie Curie IOF Fellowship.
Publisher Copyright:
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2016/4/4
Y1 - 2016/4/4
N2 - We report the CuI/O2 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)CuI]+ is unreactive towards dioxygen, the smaller analog [(12-TMC)CuI(CH3CN)]+ reacts with O2 to give a side-on bound peroxo-dicopper(II) species (SP), confirmed by spectroscopic and computational methods. Intriguingly, 12-TMC as a N4 donor ligand generates SP 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 SP species, because it reacts only with acid to release H2O2, in contrast with the classic reactivity of Cu2O2 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.
AB - We report the CuI/O2 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)CuI]+ is unreactive towards dioxygen, the smaller analog [(12-TMC)CuI(CH3CN)]+ reacts with O2 to give a side-on bound peroxo-dicopper(II) species (SP), confirmed by spectroscopic and computational methods. Intriguingly, 12-TMC as a N4 donor ligand generates SP 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 SP species, because it reacts only with acid to release H2O2, in contrast with the classic reactivity of Cu2O2 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.
KW - bioinorganic chemistry
KW - copper
KW - dioxygen reduction
KW - macrocyclic ligands
KW - metal-peroxo complexes
UR - http://www.scopus.com/inward/record.url?scp=84959419442&partnerID=8YFLogxK
U2 - 10.1002/chem.201600551
DO - 10.1002/chem.201600551
M3 - Article
C2 - 26919169
AN - SCOPUS:84959419442
VL - 22
SP - 5133
EP - 5137
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 15
ER -