TY - JOUR
T1 - A Highly Reactive Oxoiron(IV) Complex Supported by a Bioinspired N3O Macrocyclic Ligand
AU - Monte Pérez, Inés
AU - Engelmann, Xenia
AU - Lee, Yong Min
AU - Yoo, Mi
AU - Kumaran, Elumalai
AU - Farquhar, Erik R.
AU - Bill, Eckhard
AU - England, Jason
AU - Nam, Wonwoo
AU - Swart, Marcel
AU - Ray, Kallol
N1 - Funding Information:
Financial support from the DFG (Cluster of Excellence “Unifying Concepts in Catalysis”; EXC 314-2 to K.R.), MINECO (CTQ2014-59212-P and CTQ2015-70851-ERC to M.S.), GenCat (2014SGR1202 to M.S.), FEDER (UNGI10-4E-801 to M.S.), and COST action CM1305 “ECOSTBio” is gratefully acknowledged. K.R. also thanks the Heisenberg Program of the DFG for financial support. J.E. thanks the NTU for funding. W.N. and Y.-M.L. acknowledge financial support from the NRF of Korea through CRI (NRF-2012R1A3A2048842 to W.N.), GRL (NRF-2010-00353 to W.N.), and the Basic Science Research Program (2017R1D1A1B03029982 to Y.-M.L.). XAS experiments were conducted at the SSRL beamline 7-3 (SLAC National Accelerator Laboratory, USA), with support from the DOE Office of Science (DE-AC02-76SF00515) and the NIH (P30-EB-009998 and P41-GM-103393).
Publisher Copyright:
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2017/11/13
Y1 - 2017/11/13
N2 - The sluggish oxidants [FeIV(O)(TMC)(CH3CN)]2+ (TMC=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and [FeIV(O)(TMCN-d12)(OTf)]+ (TMCN-d12=1,4,7,11-tetra(methyl-d3)-1,4,7,11-tetraazacyclotetradecane) are transformed into the highly reactive oxidant [FeIV(O)(TMCO)(OTf)]+ (1; TMCO=4,8,12-trimethyl-1-oxa-4,8,12-triazacyclotetradecane) upon replacement of an NMe donor in the TMC and TMCN ligands by an O atom. A rate enhancement of five to six orders of magnitude in both H atom and O atom transfer reactions was observed upon oxygen incorporation into the macrocyclic ligand. This finding was explained in terms of the higher electrophilicity of the iron center and the higher availability of the more reactive S=2 state in 1. This rationalizes nature's preference for using O-rich ligand environments for the hydroxylation of strong C−H bonds in enzymatic reactions.
AB - The sluggish oxidants [FeIV(O)(TMC)(CH3CN)]2+ (TMC=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and [FeIV(O)(TMCN-d12)(OTf)]+ (TMCN-d12=1,4,7,11-tetra(methyl-d3)-1,4,7,11-tetraazacyclotetradecane) are transformed into the highly reactive oxidant [FeIV(O)(TMCO)(OTf)]+ (1; TMCO=4,8,12-trimethyl-1-oxa-4,8,12-triazacyclotetradecane) upon replacement of an NMe donor in the TMC and TMCN ligands by an O atom. A rate enhancement of five to six orders of magnitude in both H atom and O atom transfer reactions was observed upon oxygen incorporation into the macrocyclic ligand. This finding was explained in terms of the higher electrophilicity of the iron center and the higher availability of the more reactive S=2 state in 1. This rationalizes nature's preference for using O-rich ligand environments for the hydroxylation of strong C−H bonds in enzymatic reactions.
KW - O ligands
KW - hydrogen atom transfer
KW - oxoiron(IV) complexes
KW - oxygen atom transfer
KW - spin state
UR - http://www.scopus.com/inward/record.url?scp=85031499656&partnerID=8YFLogxK
U2 - 10.1002/anie.201707872
DO - 10.1002/anie.201707872
M3 - Article
C2 - 28945949
AN - SCOPUS:85031499656
VL - 56
SP - 14384
EP - 14388
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
SN - 1433-7851
IS - 46
ER -