TY - JOUR
T1 - Non-Heme Diiron Model Complexes Can Mediate Direct NO Reduction
T2 - Mechanistic Insight into Flavodiiron NO Reductases
AU - Dong, Hai T.
AU - White, Corey J.
AU - Zhang, Bo
AU - Krebs, Carsten
AU - Lehnert, Nicolai
N1 - Funding Information:
This work was supported by the National Science Foundation (CHE-1608331 to N.L.). We acknowledge Dr. Jeff Kampf (University of Michigan) for X-ray crystallographic analysis of 2-OAc, and funding from National Science Foundation grant CHE-0840456 for X-ray instrumentation.
Publisher Copyright:
© Copyright 2018 American Chemical Society.
PY - 2018/10/17
Y1 - 2018/10/17
N2 - Flavodiiron nitric oxide reductases (FNORs), a common enzyme family found in various types of pathogenic bacteria, are capable of reducing nitric oxide (NO) to nitrous oxide (N2O) as a protective detoxification mechanism. Utilization of FNORs in pathogenic bacteria helps them survive and proliferate in the human body, thus causing chronic infections. In this paper, we present a new diiron model complex, [Fe2((Py2PhO2)MP)(OPr)2](OTf), with bridging propionate ligands (OPr-) that is capable of directly reducing NO to N2O in quantitative yield without the need to (super)reduce the complex. We first prepared the diferric precursor and characterized it by UV-vis, IR, NMR and Mössbauer spectroscopies, cyclic voltammetry, and mass spectrometry. This complex can then conveniently be reduced to the diferrous complex using CoCp2. Even though this diferrous complex is highly reactive, we have successfully isolated and characterized this species using X-ray crystallography and various spectroscopic techniques. Most importantly, upon reacting this diferrous complex with NO gas, we observe quantitative formation of N2O via IR gas headspace analysis, the first demonstration of direct NO reduction by a non-heme diiron model complex. This finding directly supports recent mechanistic proposals for FNORs.
AB - Flavodiiron nitric oxide reductases (FNORs), a common enzyme family found in various types of pathogenic bacteria, are capable of reducing nitric oxide (NO) to nitrous oxide (N2O) as a protective detoxification mechanism. Utilization of FNORs in pathogenic bacteria helps them survive and proliferate in the human body, thus causing chronic infections. In this paper, we present a new diiron model complex, [Fe2((Py2PhO2)MP)(OPr)2](OTf), with bridging propionate ligands (OPr-) that is capable of directly reducing NO to N2O in quantitative yield without the need to (super)reduce the complex. We first prepared the diferric precursor and characterized it by UV-vis, IR, NMR and Mössbauer spectroscopies, cyclic voltammetry, and mass spectrometry. This complex can then conveniently be reduced to the diferrous complex using CoCp2. Even though this diferrous complex is highly reactive, we have successfully isolated and characterized this species using X-ray crystallography and various spectroscopic techniques. Most importantly, upon reacting this diferrous complex with NO gas, we observe quantitative formation of N2O via IR gas headspace analysis, the first demonstration of direct NO reduction by a non-heme diiron model complex. This finding directly supports recent mechanistic proposals for FNORs.
UR - https://www.scopus.com/pages/publications/85054607744
UR - https://www.scopus.com/pages/publications/85054607744#tab=citedBy
U2 - 10.1021/jacs.8b08567
DO - 10.1021/jacs.8b08567
M3 - Article
C2 - 30220202
AN - SCOPUS:85054607744
SN - 0002-7863
VL - 140
SP - 13429
EP - 13440
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 41
ER -