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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: 96] [Impact Index Per Article: 32.0] [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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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] [MESH Headings] [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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3
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Cho SL, Liao CJ, Lu TT. Synthetic methodology for preparation of dinitrosyl iron complexes. J Biol Inorg Chem 2019; 24:495-515. [DOI: 10.1007/s00775-019-01668-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/15/2019] [Indexed: 12/29/2022]
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Lu TT, Wang YM, Hung CH, Chiou SJ, Liaw WF. Bioinorganic Chemistry of the Natural [Fe(NO)2] Motif: Evolution of a Functional Model for NO-Related Biomedical Application and Revolutionary Development of a Translational Model. Inorg Chem 2018; 57:12425-12443. [DOI: 10.1021/acs.inorgchem.8b01818] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | - Yun-Ming Wang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30013, Taiwan
| | | | - Show-Jen Chiou
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
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Ghosh P, Ding S, Chupik RB, Quiroz M, Hsieh CH, Bhuvanesh N, Hall MB, Darensbourg MY. A matrix of heterobimetallic complexes for interrogation of hydrogen evolution reaction electrocatalysts. Chem Sci 2017; 8:8291-8300. [PMID: 29619175 PMCID: PMC5858031 DOI: 10.1039/c7sc03378h] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/11/2017] [Indexed: 11/21/2022] Open
Abstract
Experimental and computational studies address key questions in a structure-function analysis of bioinspired electrocatalysts for the HER. Combinations of NiN2S2 or [(NO)Fe]N2S2 as donors to (η5-C5H5)Fe(CO)+ or [Fe(NO)2]+/0 generate a series of four bimetallics, gradually "softened" by increasing nitrosylation, from 0 to 3, by the non-innocent NO ligands. The nitrosylated NiFe complexes are isolated and structurally characterized in two redox levels, demonstrating required features of electrocatalysis. Computational modeling of experimental structures and likely transient intermediates that connect the electrochemical events find roles for electron delocalization by NO, as well as Fe-S bond dissociation that produce a terminal thiolate as pendant base well positioned to facilitate proton uptake and transfer. Dihydrogen formation is via proton/hydride coupling by internal S-H+···-H-Fe units of the "harder" bimetallic arrangements with more localized electron density, while softer units convert H-···H-via reductive elimination from two Fe-H deriving from the highly delocalized, doubly reduced [Fe2(NO)3]- derivative. Computational studies also account for the inactivity of a Ni2Fe complex resulting from entanglement of added H+ in a pinched -S δ-···H+··· δ-S- arrangement.
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Affiliation(s)
- Pokhraj Ghosh
- Department of Chemistry , Texas A & M University , College Station , TX 77843 , USA .
| | - Shengda Ding
- Department of Chemistry , Texas A & M University , College Station , TX 77843 , USA .
| | - Rachel B Chupik
- Department of Chemistry , Texas A & M University , College Station , TX 77843 , USA .
| | - Manuel Quiroz
- Department of Chemistry , Texas A & M University , College Station , TX 77843 , USA .
| | - Chung-Hung Hsieh
- Department of Chemistry , Tamkang University , New Taipei City , Taiwan 25157
| | - Nattami Bhuvanesh
- Department of Chemistry , Texas A & M University , College Station , TX 77843 , USA .
| | - Michael B Hall
- Department of Chemistry , Texas A & M University , College Station , TX 77843 , USA .
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Georgopoulou AN, Al-Ameed K, Boudalis AK, Anagnostopoulos DF, Psycharis V, McGrady JE, Sanakis Y, Raptopoulou CP. Site preferences in hetero-metallic [Fe 9-xNi x] clusters: a combined crystallographic, spectroscopic and theoretical analysis. Dalton Trans 2017; 46:12835-12844. [PMID: 28920627 DOI: 10.1039/c7dt02930f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of mixtures of Fe(O2CMe)2·2H2O and Ni(O2CMe)2·4H2O of various compositions with di-2-pyridyl ketone (py2CO, dpk) in MeCN under an inert atmosphere afforded a family of hetero-metallic enneanuclear clusters with general formula [Fe9-xNix(μ4-OH)2(O2CMe)8(py2CO2)4] (2, x = 1.00; 3: x = 6.02; 4, x = 7.46; 5, x = 7.81). Clusters 2-5 are isomorphous to the homo-metallic [Fe9] cluster (1) previously reported by some of us, and also isostructural to the known homo-metallic [Ni9] cluster. All four clusters contain a central MII ion in an unusual 8-coordinate site and eight peripheral MII ions in distorted octahedral environments. The distribution of FeII and NiII ions over these two distinct coordination sites in 2-5 can be established through a combination of X-ray fluorescence and Mössbauer spectroscopies, which show that FeII preferentially occupies the unique 8-coordinate metal site while NiII accumulates in the octahedral holes. Density functional theory indicates that the distribution of ions across the two sites arises not from any intrinsic preference of the FeII ions for the 8-coordinate sites, but rather because of the large ligand field stabilization energy available to NiII in octahedral coordination.
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Affiliation(s)
- Anastasia N Georgopoulou
- Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Aghia Paraskevi, Athens, Greece.
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Chu X, Yu X, Raje S, Angamuthu R, Ma J, Tung CH, Wang W. Synthetic [NiFe] models with a fluxional CO ligand. Dalton Trans 2017; 46:13681-13685. [DOI: 10.1039/c7dt02892j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A [NiFe] complex [(dppe)Ni(pdt)FeCp*(CO)]BF4 was characterized as two isomers, and their interconversions were established by thermal process and electrochemistry.
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Affiliation(s)
- Xiaoxiao Chu
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Xin Yu
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Sakthi Raje
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur
- India
| | - Raja Angamuthu
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur
- India
| | - Jianping Ma
- College of Chemistry
- Chemical Engineering and Materials Science Shandong Normal University
- Jinan 250014
- PR China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
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Pulukkody R, Darensbourg MY. Synthetic advances inspired by the bioactive dinitrosyl iron unit. Acc Chem Res 2015; 48:2049-58. [PMID: 26090911 DOI: 10.1021/acs.accounts.5b00215] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Resulting from biochemical iron-NO interactions, dinitrosyl iron complexes (DNICs) are small organometallic-like molecules, considered to serve as vehicles for NO transport and storage in vivo. Formed by the interaction of NO with cellular iron sulfur clusters or with the cellular labile iron pool, DNICs have been documented to be the largest NO-derived adduct in cells, even surpassing the well-known nitrosothiols (RSNOs). Continuing efforts in biological chemistry are aimed at understanding the movement of DNICs in and out of cells, and their important role in NO-induced iron efflux leading to apoptosis in cells. Intrigued by the integrity of the unique dinitrosyl iron unit (DNIU) and the possibility of roles for it in human physiology or medicinal applications, the understanding of fundamental properties such as ligand effects on its ability to switch between two redox levels has been pursued through biomimetic complexes. Using metallodithiolates and N-heterocyclic carbenes (NHCs) as ligands to Fe(NO)2, the synthesis of a library of novel DNICs, in both the oxidized, {Fe(NO)2}(9), and reduced, {Fe(NO)2}(10), forms (Enemark-Feltham notation), offers opportunity to examine structural, reactivity, and spectroscopic features. The raison d'etre for the MN2S2·Fe(NO)2 synthesis development is for the potential to exploit the ease of accessing two redox levels on two different metal sites, a property presumably required for achieving two electron redox processes in base metals. Hence such molecules may be viewed as synthetic analogues of [NiFe]- or [FeFe]-hydrogenase active sites in nature, both of which use bridging thiolates for connection of the two centers. A particular success was the development of an Fe(NO)N2S2·Fe(NO)2(+/0) redox pair for proton reduction electrocatalysis. Monomeric, reduced NHC-DNICs of the L2Fe(NO)2 type are synthesized via the Fe(CO)2(NO)2 precursor, and oxidized thiolate-containing forms are derived from the dimeric (μ-RS)2[Fe(NO)2]2. Monomeric NHC-DNICs are four coordinate, pseudotetrahedral compounds with planar Fe(NO)2 units in which the slightly bent Fe-NO groups are directed symmetrically inward at both redox levels. They serve as stable analogues of biological histidine binding sites. In agreement with IR data, Mössbauer spectroscopic parameters, and DFT computations, the prototypic NHC-DNICs indicate extensive delocalization of the electron density of iron via π-backbonding. Such π-delocalization presents an unusual reaction path for the one electron process of RS(-)/RSSR interconversion. Comparisons with imidazole-DNICs find NHCs to be the "better" ligands to Fe(NO)2 and prompted investigations in (a) possible relationships between such imidazole- and NHC-containing DNICs, (b) systems that might mimic the reactivity of DNICs with the endogenous gaseotransmitter CO, and (c) mechanistic details of such processes. In a broader context, these studies aim to further describe the behavior of the {Fe(NO)2} unit as a single molecular entity when subjected to various ligand environments and reaction conditions.
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Affiliation(s)
- Randara Pulukkody
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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9
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Denny JA, Darensbourg MY. Metallodithiolates as ligands in coordination, bioinorganic, and organometallic chemistry. Chem Rev 2015; 115:5248-73. [PMID: 25948147 DOI: 10.1021/cr500659u] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Abstract
The coordination chemistry of metal nitrosyls has expanded rapidly in the past decades due to major advances of nitric oxide and its metal compounds in biology. This review article highlights advances made in the area of multinuclear metal nitrosyl complexes, including Roussin's salts and their ester derivatives from 2003 to present. The review article focuses on isolated multinuclear metal nitrosyl complexes and is organized into different sections by the number of metal centers and bridging ligands.
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11
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Lach J, Jeremies A, Breite D, Abel B, Mahns B, Knupfer M, Matulis V, Ivashkevich OA, Kersting B. Encapsulation of the 4-Mercaptobenzoate Ligand by Macrocyclic Metal Complexes: Conversion of a Metallocavitand to a Metalloligand. Inorg Chem 2014; 53:10825-34. [DOI: 10.1021/ic500683f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jochen Lach
- Institut für Anorganische Chemie, Universität Leipzig, D-04103 Leipzig, Germany
| | - Alexander Jeremies
- Institut für Anorganische Chemie, Universität Leipzig, D-04103 Leipzig, Germany
| | - Daniel Breite
- Chemische Abteilung, Leibniz Institut für Oberflächenmodifizierung eV, D-04318 Leipzig, Germany
| | - Bernd Abel
- Chemische Abteilung, Leibniz Institut für Oberflächenmodifizierung eV, D-04318 Leipzig, Germany
| | - Benjamin Mahns
- Leibniz Institute for Solid State and Materials
Research, IFW Dresden, D-01171 Dresden, Germany
| | - Martin Knupfer
- Leibniz Institute for Solid State and Materials
Research, IFW Dresden, D-01171 Dresden, Germany
| | - Vitaly Matulis
- Research Institute for Physical Chemical Problems of Belarusian State University, Leningradskaya 14, 220030 Minsk, Belarus
| | | | - Berthold Kersting
- Institut für Anorganische Chemie, Universität Leipzig, D-04103 Leipzig, Germany
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12
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Pinder TA, Montalvo SK, Hsieh CH, Lunsford AM, Bethel RD, Pierce BS, Darensbourg MY. Metallodithiolates as Ligands to Dinitrosyl Iron Complexes: Toward the Understanding of Structures, Equilibria, and Spin Coupling. Inorg Chem 2014; 53:9095-105. [DOI: 10.1021/ic501117f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Tiffany A. Pinder
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Steven K. Montalvo
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Chung-Hung Hsieh
- Department of Chemistry, Tamkang University, New Taipei
City 25157, Taiwan
| | - Allen M. Lunsford
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Ryan D. Bethel
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Brad S. Pierce
- Department of Chemistry and Biochemistry, College of Sciences, The University of Texas at Arlington, Arlington, Texas 76019, United States
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Kaur-Ghumaan S, Stein M. [NiFe] hydrogenases: how close do structural and functional mimics approach the active site? Dalton Trans 2014; 43:9392-405. [DOI: 10.1039/c4dt00539b] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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14
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Hsieh CH, Chupik RB, Pinder TA, Darensbourg MY. Dinitrosyl iron adducts of (N2S2)M(NO) complexes (M=Fe, Co) as metallodithiolate ligands. Polyhedron 2013. [DOI: 10.1016/j.poly.2012.09.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Weber K, Krämer T, Shafaat HS, Weyhermüller T, Bill E, van Gastel M, Neese F, Lubitz W. A Functional [NiFe]-Hydrogenase Model Compound That Undergoes Biologically Relevant Reversible Thiolate Protonation. J Am Chem Soc 2012. [DOI: 10.1021/ja309563p] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Katharina Weber
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Tobias Krämer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Hannah S. Shafaat
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Maurice van Gastel
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Frank Neese
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
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Dutta A, Hamilton GA, Hartnett HE, Jones AK. Construction of heterometallic clusters in a small peptide scaffold as [NiFe]-hydrogenase models: development of a synthetic methodology. Inorg Chem 2012; 51:9580-8. [PMID: 22924594 DOI: 10.1021/ic2026818] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
[NiFe]-hydrogenases are enzymes that catalyze the reversible interconversion of protons and hydrogen at a heterobimetallic site containing Ni and Fe. This organometallic site has served as an inspiration for the synthesis of a number of biomimetic complexes, but, unfortunately, most close structural mimics have shown little to no reactivity with either of the substrates for hydrogenases. This suggests that interactions between the metallo-active site and the protein scaffold are crucial in tuning reactivity. As a first step toward development of peptide-based models, in this paper we demonstrate a synthetic strategy for construction of peptide coordinated, cysteinyl thiolate bridged Ni-M complexes in which M is a hetero-organometallic fragment. We utilize the seven amino acid peptide ACDLPCG as a scaffold for construction of these peptide-coordinated metallocenters. This peptide binds Ni in an N(2)S(2) environment consisting of the amino terminus, an amide nitrogen, and the two cysteinyl thiolates. We show that these thiolates serve as reactive sites for formation of heterometallic complexes in which they serve as bridging ligands. The method is general, and a number of heterometallic fragments including Ru(η(6)-arene)(2+), M(CO)(4)(piperidine) for M = Mo and W, and Fe(2)(CO)(6) were successfully incorporated, and the resulting metallopeptides characterized via a range of spectroscopic techniques. This methodology serves as the first step to construction of hydrogenase peptidomimetics that incorporate defined outer coordination sphere interactions intended to tune reactivity.
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Affiliation(s)
- Arnab Dutta
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA
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Matsumoto T, Kabe R, Nonaka K, Ando T, Yoon KS, Nakai H, Ogo S. Model study of CO inhibition of [NiFe]hydrogenase. Inorg Chem 2011; 50:8902-6. [PMID: 21853978 DOI: 10.1021/ic200965t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We propose a modified mechanism for the inhibition of [NiFe]hydrogenase ([NiFe]H(2)ase) by CO. We present a model study, using a NiRu H(2)ase mimic, that demonstrates that (i) CO completely inhibits the catalytic cycle of the model compound, (ii) CO prefers to coordinate to the Ru(II) center rather than taking an axial position on the Ni(II) center, and (iii) CO is unable to displace a hydrido ligand from the NiRu center. We combine these studies with a reevaluation of previous studies to propose that, under normal circumstances, CO inhibits [NiFe]H(2)ase by complexing to the Fe(II) center.
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Affiliation(s)
- Takahiro Matsumoto
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
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