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Wu WY, Zheng WY, Chen WT, Tsai FT, Tsai ML, Pao CW, Chen JL, Liaw WF. Electronic Structure and Transformation of Dinitrosyl Iron Complexes (DNICs) Regulated by Redox Non-Innocent Imino-Substituted Phenoxide Ligand. Inorg Chem 2024; 63:2431-2442. [PMID: 38258796 PMCID: PMC10848267 DOI: 10.1021/acs.inorgchem.3c03367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024]
Abstract
The coupled NO-vibrational peaks [IR νNO 1775 s, 1716 vs, 1668 vs cm-1 (THF)] between two adjacent [Fe(NO)2] groups implicate the electron delocalization nature of the singly O-phenoxide-bridged dinuclear dinitrosyliron complex (DNIC) [Fe(NO)2(μ-ON2Me)Fe(NO)2] (1). Electronic interplay between [Fe(NO)2] units and [ON2Me]- ligand in DNIC 1 rationalizes that "hard" O-phenoxide moiety polarizes iron center(s) of [Fe(NO)2] unit(s) to enforce a "constrained" π-conjugation system acting as an electron reservoir to bestow the spin-frustrated {Fe(NO)2}9-{Fe(NO)2}9-[·ON2Me]2- electron configuration (Stotal = 1/2). This system plays a crucial role in facilitating the ligand-based redox interconversion, working in harmony to control the storage and redox-triggered transport of the [Fe(NO)2]10 unit, while preserving the {Fe(NO)2}9 core in DNICs {Fe(NO)2}9-[·ON2Me]2- [K-18-crown-6-ether)][(ON2Me)Fe(NO)2] (2) and {Fe(NO)2}9-[·ON2Me] [(ON2Me)Fe(NO)2][PF6] (3). Electrochemical studies suggest that the redox interconversion among [{Fe(NO)2}9-[·ON2Me]2-] DNIC 3 ↔ [{Fe(NO)2}9-[ON2Me]-] ↔ [{Fe(NO)2}9-[·ON2Me]] DNIC 2 are kinetically feasible, corroborated by the redox shuttle between O-bridged dimerized [(μ-ONMe)2Fe2(NO)4] (4) and [K-18-crown-6-ether)][(ONMe)Fe(NO)2] (5). In parallel with this finding, the electronic structures of [{Fe(NO)2}9-{Fe(NO)2}9-[·ON2Me]2-] DNIC 1, [{Fe(NO)2}9-[·ON2Me]2-] DNIC 2, [{Fe(NO)2}9-[·ON2Me]] DNIC 3, [{Fe(NO)2}9-[ONMe]-]2 DNIC 4, and [{Fe(NO)2}9-[·ONMe]2-] DNIC 5 are evidenced by EPR, SQUID, and Fe K-edge pre-edge analyses, respectively.
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Affiliation(s)
- Wun-Yan Wu
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wei-Yuan Zheng
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wei-Ting Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Fu-Te Tsai
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ming-Li Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Chih-Wen Pao
- National Synchrotron Radiation
Research Center, Hsinchu 30013, Taiwan
| | - Jeng-Lung Chen
- National Synchrotron Radiation
Research Center, Hsinchu 30013, Taiwan
| | - Wen-Feng Liaw
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
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2
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Bracken AJ, Dong HT, Lengel MO, Lehnert N. Exploring second coordination sphere effects in flavodiiron nitric oxide reductase model complexes. Dalton Trans 2023; 52:17360-17374. [PMID: 37938109 DOI: 10.1039/d3dt02828c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Flavodiiron nitric oxide reductases (FNORs) equip pathogens with resistance to nitric oxide (NO), an important immune defense agent in mammals, allowing these pathogens to proliferate in the human body, potentially causing chronic infections. Understanding the mechanism of how FNORs mediate the reduction of NO contributes to the greater goal of developing new therapeutic approaches against drug-resistant strains. Recent density functional theory calculations suggest that a second coordination sphere (SCS) tyrosine residue provides a hydrogen bond that is critical for the reduction of NO to N2O at the active site of FNORs [J. Lu, B. Bi, W. Lai and H. Chen, Origin of Nitric Oxide Reduction Activity in Flavo-Diiron NO Reductase: Key Roles of the Second Coordination Sphere, Angew. Chem., Int. Ed., 2019, 58, 3795-3799]. Specifically, this H-bond stabilizes the hyponitrite intermediate and reduces the energetic barrier for the N-N coupling step. At the same time, the role of the Fe⋯Fe distance and its effect on the N-N coupling step has not been fully investigated. In this study, we equipped the H[BPMP] (= 2,6-bis[[bis(2-pyridylmethyl)amino]methyl]-4-methylphenol) ligand with SCS amide groups and investigated the corresponding diiron complexes with 0-2 bridging acetate ligands. These amide groups can form hydrogen bonds with the bridging acetate ligand(s) and potentially the coordinated NO groups in these model complexes. At the same time, by changing the number of bridging acetate ligands, we can systematically vary the Fe⋯Fe distance. The reactivity of these complexes with NO was then investigated, and the formation of stable iron(II)-NO complexes was observed. Upon one-electron reduction, these NO complexes form Dinitrosyl Iron Complexes (DNICs), which were further characterized using IR and EPR spectroscopy.
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Affiliation(s)
- Abigail J Bracken
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
| | - Hai T Dong
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
| | - Michael O Lengel
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
| | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
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3
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Tseng YT, Pelmenschikov V, Iffland-Mühlhaus L, Calabrese D, Chang YC, Laun K, Pao CW, Sergueev I, Yoda Y, Liaw WF, Chen CH, Hsu IJ, Apfel UP, Caserta G, Lauterbach L, Lu TT. Substrate-Gated Transformation of a Pre-Catalyst into an Iron-Hydride Intermediate [(NO) 2(CO)Fe(μ-H)Fe(CO)(NO) 2] - for Catalytic Dehydrogenation of Dimethylamine Borane. Inorg Chem 2023; 62:769-781. [PMID: 36580657 DOI: 10.1021/acs.inorgchem.2c03278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Continued efforts are made on the development of earth-abundant metal catalysts for dehydrogenation/hydrolysis of amine boranes. In this study, complex [K-18-crown-6-ether][(NO)2Fe(μ-MePyr)(μ-CO)Fe(NO)2] (3-K-crown, MePyr = 3-methylpyrazolate) was explored as a pre-catalyst for the dehydrogenation of dimethylamine borane (DMAB). Upon evolution of H2(g) from DMAB triggered by 3-K-crown, parallel conversion of 3-K-crown into [(NO)2Fe(N,N'-MePyrBH2NMe2)]- (5) and an iron-hydride intermediate [(NO)2(CO)Fe(μ-H)Fe(CO)(NO)2]- (A) was evidenced by X-ray diffraction/nuclear magnetic resonance/infrared/nuclear resonance vibrational spectroscopy experiments and supported by density functional theory calculations. Subsequent transformation of A into complex [(NO)2Fe(μ-CO)2Fe(NO)2]- (6) is synchronized with the deactivated generation of H2(g). Through reaction of complex [Na-18-crown-6-ether][(NO)2Fe(η2-BH4)] (4-Na-crown) with CO(g) as an alternative synthetic route, isolated intermediate [Na-18-crown-6-ether][(NO)2(CO)Fe(μ-H)Fe(CO)(NO)2] (A-Na-crown) featuring catalytic reactivity toward dehydrogenation of DMAB supports a substrate-gated transformation of a pre-catalyst [(NO)2Fe(μ-MePyr)(μ-CO)Fe(NO)2]- (3) into the iron-hydride species A as an intermediate during the generation of H2(g).
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Affiliation(s)
- Yu-Ting Tseng
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | | | - Linda Iffland-Mühlhaus
- Department of Chemistry and Biochemistry, Inorganic Chemistry Ι, Ruhr-Universität Bochum, Bochum 44801, Germany
| | - Donato Calabrese
- Institute of Applied Microbiology, RWTH Aachen University, Aachen 52074, Germany
| | - Yu-Che Chang
- Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Konstantin Laun
- Institut für Chemie, Technische Universität Berlin, Berlin 10623, Germany
| | - Chih-Wen Pao
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Ilya Sergueev
- Deutsches Elektronen-Synchrotron DESY, Hamburg D-22607, Germany
| | | | - Wen-Feng Liaw
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chien-Hong Chen
- Department of Medical Applied Chemistry, Chung Shan Medical University and Department of Medical Education, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
| | - I-Jui Hsu
- Department of Molecular Science and Engineering, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan
| | - Ulf-Peter Apfel
- Department of Chemistry and Biochemistry, Inorganic Chemistry Ι, Ruhr-Universität Bochum, Bochum 44801, Germany.,Department for Electrosynthesis, Fraunhofer UMSICHT, Oberhausen 46047, Germany
| | - Giorgio Caserta
- Institut für Chemie, Technische Universität Berlin, Berlin 10623, Germany
| | - Lars Lauterbach
- Institute of Applied Microbiology, RWTH Aachen University, Aachen 52074, Germany
| | - Tsai-Te Lu
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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Lehnert N, Kim E, Dong HT, Harland JB, Hunt AP, Manickas EC, Oakley KM, Pham J, Reed GC, Alfaro VS. The Biologically Relevant Coordination Chemistry of Iron and Nitric Oxide: Electronic Structure and Reactivity. Chem Rev 2021; 121:14682-14905. [PMID: 34902255 DOI: 10.1021/acs.chemrev.1c00253] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) is an important signaling molecule that is involved in a wide range of physiological and pathological events in biology. Metal coordination chemistry, especially with iron, is at the heart of many biological transformations involving NO. A series of heme proteins, nitric oxide synthases (NOS), soluble guanylate cyclase (sGC), and nitrophorins, are responsible for the biosynthesis, sensing, and transport of NO. Alternatively, NO can be generated from nitrite by heme- and copper-containing nitrite reductases (NIRs). The NO-bearing small molecules such as nitrosothiols and dinitrosyl iron complexes (DNICs) can serve as an alternative vehicle for NO storage and transport. Once NO is formed, the rich reaction chemistry of NO leads to a wide variety of biological activities including reduction of NO by heme or non-heme iron-containing NO reductases and protein post-translational modifications by DNICs. Much of our understanding of the reactivity of metal sites in biology with NO and the mechanisms of these transformations has come from the elucidation of the geometric and electronic structures and chemical reactivity of synthetic model systems, in synergy with biochemical and biophysical studies on the relevant proteins themselves. This review focuses on recent advancements from studies on proteins and model complexes that not only have improved our understanding of the biological roles of NO but also have provided foundations for biomedical research and for bio-inspired catalyst design in energy science.
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Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eunsuk Kim
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hai T Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jill B Harland
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Andrew P Hunt
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Elizabeth C Manickas
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Kady M Oakley
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - John Pham
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Garrett C Reed
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Victor Sosa Alfaro
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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Marks WR, Reinheimer EW, Seda T, Zakharov LN, Gilbertson JD. NO Coupling by Nonclassical Dinuclear Dinitrosyliron Complexes to Form N 2O Dictated by Hemilability. Inorg Chem 2021; 60:15901-15909. [PMID: 34514780 DOI: 10.1021/acs.inorgchem.1c02285] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Selective coupling of NO by a nonclassical dinuclear dinitrosyliron complex (D-DNIC) to form N2O is reported. The coupling is facilitated by the pyridinediimine (PDI) ligand scaffold, which enables the necessary denticity changes to produce mixed-valent, electron-deficient tethered DNICs. One-electron oxidation of the [{Fe(NO)2}]210/10 complex Fe2(PyrrPDI)(NO)4 (4) results in NO coupling to form N2O via the mixed-valent {[Fe(NO)2]2}9/10 species, which possesses an electron-deficient four-coordinate {Fe(NO)2}10 site, crucial in N-N bond formation. The hemilability of the PDI scaffold dictates the selectivity in N-N bond formation because stabilization of the five-coordinate {Fe(NO)2}9 site in the mixed-valent [{Fe(NO)2}]29/10 species, [Fe2(Pyr2PDI)(NO)4][PF6] (6), does not result in an electron-deficient, four-coordinate {Fe(NO)2}10 site, and hence no N-N coupling is observed.
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Affiliation(s)
- Walker R Marks
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225, United States
| | | | - Takele Seda
- Department of Physics, Western Washington University, Bellingham, Washington 98225, United States
| | - Lev N Zakharov
- Department of Chemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - John D Gilbertson
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225, United States
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6
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Wu WY, Tsai ML, Lai YA, Hsieh CH, Liaw WF. NO Reduction to N2O Triggered by a Dinuclear Dinitrosyl Iron Complex via the Associated Pathways of Hyponitrite Formation and NO Disproportionation. Inorg Chem 2021; 60:15874-15889. [DOI: 10.1021/acs.inorgchem.1c00541] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wun-Yan Wu
- Department of Chemistry and Frontier Research Center of Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ming-Li Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Yi-An Lai
- Department of Chemistry and Frontier Research Center of Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chieh-Hsin Hsieh
- Department of Chemistry and Frontier Research Center of Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wen-Feng Liaw
- Department of Chemistry and Frontier Research Center of Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
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7
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Tung CY, Tseng YT, Lu TT, Liaw WF. Insight into the Electronic Structure of Biomimetic Dinitrosyliron Complexes (DNICs): Toward the Syntheses of Amido-Bridging Dinuclear DNICs. Inorg Chem 2021; 60:15846-15873. [PMID: 34009960 DOI: 10.1021/acs.inorgchem.1c00566] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ubiquitous function of nitric oxide (NO) guided the biological discovery of the natural dinitrosyliron unit (DNIU) [Fe(NO)2] as an intermediate/end product after Fe nitrosylation of nonheme cofactors. Because of the natural utilization of this cofactor for the biological storage and delivery of NO, a bioinorganic study of synthetic dinitrosyliron complexes (DNICs) has been extensively explored in the last 2 decades. The bioinorganic study of DNICs involved the development of synthetic methodology, spectroscopic discrimination, biological application of NO-delivery reactivity, and translational application to the (catalytic) transformation of small molecules. In this Forum Article, we aim to provide a systematic review of spectroscopic and computational insights into the bonding nature within the DNIU [Fe(NO)2] and the electronic structure of different types of DNICs, which highlights the synchronized advance in synthetic methodology and spectroscopic tools. With regard to the noninnocent nature of a NO ligand, spectroscopic and computational tools were utilized to provide qualitative/quantitative assignment of oxidation states of Fe and NO in DNICs with different redox levels and ligation modes as well as to probe the Fe-NO bonding interaction modulated by supporting ligands. Besides the strong antiferromagnetic coupling between high-spin Fe and paramagnetic NO ligands within the covalent DNIU [Fe(NO)2], in polynuclear DNICs, the effects of the Fe···Fe distance, nature of the bridging ligands, and type of bridging modes on the regulation of the magnetic coupling among paramagnetic DNIU [Fe(NO)2] are further reviewed. In the last part of this Forum Article, the sequential reaction of {Fe(NO)2}10 DNIC [(NO)2Fe(AMP)] (1-red) with NO(g), HBF4, and KC8 establishes a synthetic cycle, {Fe(NO)2}9-{Fe(NO)2}9 DNIC [(NO)2Fe(μ-dAMP)2Fe(NO)2] (1) → {Fe(NO)2}9 DNIC [(NO2)Fe(AMP)][BF4] (1-H) → {Fe(NO)2}10 DNIC 1-red → DNIC 1, for the transformation of NO into HNO/N2O. Of importance, the NO-induced transformation of {Fe(NO)2}10 DNIC 1-red and [(NO)2Fe(DTA)] (2-red; DTA = diethylenetriamine) unravels a synthetic strategy for preparation of the {Fe(NO)2}9-{Fe(NO)2}9 DNICs [(NO)2Fe(μ-NHR)2Fe(NO)2] containing amido-bridging ligands, which hold the potential to feature distinctive physical properties, chemical reactivities, and biological applications.
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Affiliation(s)
- Chi-Yen Tung
- Department of Chemistry, National Tsing Hua University (NTHU), Hsinchu 30013 Taiwan
| | - Yu-Ting Tseng
- Department of Chemistry, National Tsing Hua University (NTHU), Hsinchu 30013 Taiwan
| | - Tsai-Te Lu
- Institute of Biomedical Engineering, National Tsing Hua University (NTHU), Hsinchu 30013, Taiwan
| | - Wen-Feng Liaw
- Department of Chemistry, National Tsing Hua University (NTHU), Hsinchu 30013 Taiwan
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