Structural implications of the paramagnetically shifted NMR signals from pyridine H atoms on synthetic nonheme FeIV=O complexes

Waqas Rasheed; Ruixi Fan; Chase S Abelson; Paul O. Peterson; Wei-Min Ching; Yisong Guo; Lawrence Que

doi:10.1007/s00775-019-01672-3

Structural implications of the paramagnetically shifted NMR signals from pyridine H atoms on synthetic nonheme Fe^IV=O complexes

Waqas Rasheed, Ruixi Fan, Chase S Abelson, Paul O. Peterson, Wei-Min Ching, Yisong Guo, Lawrence Que

Chemistry (Twin Cities)

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

Oxoiron(IV) motifs are found in important intermediates in many enzymatic cycles that involve oxidations. Over half of the reported synthetic nonheme oxoiron(IV) analogs incorporate heterocyclic donors, with a majority of them comprising pyridines. Herein, we report ¹H-NMR studies of oxoiron(IV) complexes containing pyridines that are arranged in different configurations relative to the Fe = O unit and give rise to paramagnetically shifted resonances that differ by as much as 50 ppm. The strong dependence of ¹H-NMR shifts on the different configurations and orientation of pyridines relative to the oxoiron(IV) unit demonstrates how unpaired electronic spin density of the iron center affects the chemical shifts of these protons.

Original language	English (US)
Pages (from-to)	533-545
Number of pages	13
Journal	Journal of Biological Inorganic Chemistry
Volume	24
Issue number	4
DOIs	https://doi.org/10.1007/s00775-019-01672-3
State	Published - Jun 1 2019

Bibliographical note

Funding Information:
We gratefully acknowledge the support of the U.S. National Science Foundation (Grants CHE-1665391 to L.Q. and CHE-1654060 to Y.G.). The Bruker Avance III HD nanobay 400?MHz spectrometer used in this study was purchased from funds provided by the Office of the Vice President of Research, the College of Science and Engineering, and the Department of Chemistry at the University of Minnesota. The Bruker-AXS D8 Venture Diffractometer was purchased through a grant from NSF/MRI 1229400 and the University of Minnesota. We thank Dr. Letitia Yao for her help with NMR experiments and Dr Victor G. Young and Shuangning Xu for their valuable input on X-ray crystallography. We also thank the Pittsburgh Supercomputing Center for granting us computational resources (CHE180020P to R.F. and Y.G.).

Publisher Copyright:
© 2019, Society for Biological Inorganic Chemistry (SBIC).

Keywords

Iron(IV)-oxo complexes
NMR
Nonheme iron

Publisher link

10.1007/s00775-019-01672-3

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title = "Structural implications of the paramagnetically shifted NMR signals from pyridine H atoms on synthetic nonheme FeIV=O complexes",

abstract = "Oxoiron(IV) motifs are found in important intermediates in many enzymatic cycles that involve oxidations. Over half of the reported synthetic nonheme oxoiron(IV) analogs incorporate heterocyclic donors, with a majority of them comprising pyridines. Herein, we report 1H-NMR studies of oxoiron(IV) complexes containing pyridines that are arranged in different configurations relative to the Fe = O unit and give rise to paramagnetically shifted resonances that differ by as much as 50 ppm. The strong dependence of 1H-NMR shifts on the different configurations and orientation of pyridines relative to the oxoiron(IV) unit demonstrates how unpaired electronic spin density of the iron center affects the chemical shifts of these protons.",

keywords = "Iron(IV)-oxo complexes, NMR, Nonheme iron",

author = "Waqas Rasheed and Ruixi Fan and Abelson, {Chase S} and Peterson, {Paul O.} and Wei-Min Ching and Yisong Guo and Lawrence Que",

note = "Funding Information: We gratefully acknowledge the support of the U.S. National Science Foundation (Grants CHE-1665391 to L.Q. and CHE-1654060 to Y.G.). The Bruker Avance III HD nanobay 400?MHz spectrometer used in this study was purchased from funds provided by the Office of the Vice President of Research, the College of Science and Engineering, and the Department of Chemistry at the University of Minnesota. The Bruker-AXS D8 Venture Diffractometer was purchased through a grant from NSF/MRI 1229400 and the University of Minnesota. We thank Dr. Letitia Yao for her help with NMR experiments and Dr Victor G. Young and Shuangning Xu for their valuable input on X-ray crystallography. We also thank the Pittsburgh Supercomputing Center for granting us computational resources (CHE180020P to R.F. and Y.G.). Publisher Copyright: {\textcopyright} 2019, Society for Biological Inorganic Chemistry (SBIC).",

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T1 - Structural implications of the paramagnetically shifted NMR signals from pyridine H atoms on synthetic nonheme FeIV=O complexes

AU - Rasheed, Waqas

AU - Fan, Ruixi

AU - Abelson, Chase S

AU - Peterson, Paul O.

AU - Ching, Wei-Min

AU - Guo, Yisong

AU - Que, Lawrence

N1 - Funding Information: We gratefully acknowledge the support of the U.S. National Science Foundation (Grants CHE-1665391 to L.Q. and CHE-1654060 to Y.G.). The Bruker Avance III HD nanobay 400?MHz spectrometer used in this study was purchased from funds provided by the Office of the Vice President of Research, the College of Science and Engineering, and the Department of Chemistry at the University of Minnesota. The Bruker-AXS D8 Venture Diffractometer was purchased through a grant from NSF/MRI 1229400 and the University of Minnesota. We thank Dr. Letitia Yao for her help with NMR experiments and Dr Victor G. Young and Shuangning Xu for their valuable input on X-ray crystallography. We also thank the Pittsburgh Supercomputing Center for granting us computational resources (CHE180020P to R.F. and Y.G.). Publisher Copyright: © 2019, Society for Biological Inorganic Chemistry (SBIC).

PY - 2019/6/1

Y1 - 2019/6/1

N2 - Oxoiron(IV) motifs are found in important intermediates in many enzymatic cycles that involve oxidations. Over half of the reported synthetic nonheme oxoiron(IV) analogs incorporate heterocyclic donors, with a majority of them comprising pyridines. Herein, we report 1H-NMR studies of oxoiron(IV) complexes containing pyridines that are arranged in different configurations relative to the Fe = O unit and give rise to paramagnetically shifted resonances that differ by as much as 50 ppm. The strong dependence of 1H-NMR shifts on the different configurations and orientation of pyridines relative to the oxoiron(IV) unit demonstrates how unpaired electronic spin density of the iron center affects the chemical shifts of these protons.

AB - Oxoiron(IV) motifs are found in important intermediates in many enzymatic cycles that involve oxidations. Over half of the reported synthetic nonheme oxoiron(IV) analogs incorporate heterocyclic donors, with a majority of them comprising pyridines. Herein, we report 1H-NMR studies of oxoiron(IV) complexes containing pyridines that are arranged in different configurations relative to the Fe = O unit and give rise to paramagnetically shifted resonances that differ by as much as 50 ppm. The strong dependence of 1H-NMR shifts on the different configurations and orientation of pyridines relative to the oxoiron(IV) unit demonstrates how unpaired electronic spin density of the iron center affects the chemical shifts of these protons.

KW - Iron(IV)-oxo complexes

KW - NMR

KW - Nonheme iron

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