1
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Lee YS, Gerulskis R, Minteer SD. Advances in electrochemical cofactor regeneration: enzymatic and non-enzymatic approaches. Curr Opin Biotechnol 2021; 73:14-21. [PMID: 34246871 DOI: 10.1016/j.copbio.2021.06.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/12/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
Nicotinamide adenine dinucleotide(NAD(P)H) is a metabolically interconnected redox cofactor serving as a hydride source for the majority of oxidoreductases, and consequently constituting a significant cost factor for bioprocessing. Much research has been devoted to the development of efficient, affordable, and sustainable methods for the regeneration of these cofactors through chemical, electrochemical, and photochemical approaches. However, the enzymatic approach using formate dehydrogenase is still the most abundantly employed in industrial applications, even though it suffers from system complexity and product purity issues. In this review, we summarize non-enzymatic and enzymatic electrochemical approaches for cofactor regeneration, then discuss recent developments to solve major issues. Issues discussed include Rh-catalyst mediated enzyme mutual inactivation, electron-transfer rates, catalyst sustainability, product selectivity and simplifying product purification. Recently reported remedies are discussed, such as heterogeneous metal catalysts generating H+ as the sole byproduct or high activity and stability redox-polymer immobilized enzymatic systems for sustainable organic synthesis.
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Affiliation(s)
- Yoo Seok Lee
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, UT 84112, USA.
| | - Rokas Gerulskis
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, UT 84112, USA
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, UT 84112, USA.
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2
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Matsubara Y, Kosaka T, Nagasawa A, Yoshida Y, Sakuma R, Masano N, Ishitani O. Theoretical Insight into the Importance of a Carbamoyl Group in the Hydride Transfer from a Ruthenium Complex to a Pyridinium. CHEM LETT 2020. [DOI: 10.1246/cl.190937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yasuo Matsubara
- Department of Material and Life Chemistry, Kanagawa University, Rokkakubashi, Yokohama, Kanagawa 221-8686, Japan
| | - Tatsumi Kosaka
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Akira Nagasawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Yukino Yoshida
- Department of Material and Life Chemistry, Kanagawa University, Rokkakubashi, Yokohama, Kanagawa 221-8686, Japan
| | - Ryuji Sakuma
- Department of Material and Life Chemistry, Kanagawa University, Rokkakubashi, Yokohama, Kanagawa 221-8686, Japan
| | - Nana Masano
- Department of Material and Life Chemistry, Kanagawa University, Rokkakubashi, Yokohama, Kanagawa 221-8686, Japan
| | - Osamu Ishitani
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
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3
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Fukuzumi S, Lee YM, Nam W. Catalytic recycling of NAD(P)H. J Inorg Biochem 2019; 199:110777. [PMID: 31376683 DOI: 10.1016/j.jinorgbio.2019.110777] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 12/15/2022]
Abstract
A large number of industrially relevant enzymes depend upon dihydronicotinamide adenine dinucleotide (NADH) and dihydronicotinamide adenine dinucleotide phosphate (NADPH) cofactors, which are too expensive to be added in stoichiometric amounts. Existing NAD(P)H-recycling systems suffer from low activity, or the generation of side products. This review focuses on NAD(P)H cofactor regeneration catalyzed by transition metal complexes such as rhodium, ruthenium and iridium complexes using cheap reducing agents such as hydrogen (H2) and ethanol, which have attracted increasing attention as sustainable energy carriers. The catalytic mechanisms for the regioselective reduction of NAD(P)+ are discussed with emphasis on identification of catalytically active intermediates such as transition metal hydride complexes. Applications of NAD(P)H-recycling systems to develop artificial photosynthesis are also discussed.
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Affiliation(s)
- Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea; Faculty of Science and Engineering, Meijo University, Nagoya, Aichi 468-8502, Japan.
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea; Research Institute for Basic Sciences, Ewha Womans University, Seoul 03760, Republic of Korea.
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea; State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou 730000, China.
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4
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Zhang F, Xu X, Zhao Y, Jia J, Tung CH, Wang W. Solvent Effects on Hydride Transfer from Cp*(P-P)FeH to BNA+ Cation. Organometallics 2017. [DOI: 10.1021/acs.organomet.6b00907] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fanjun Zhang
- School of Chemistry and Chemical
Engineering, Shandong University, No. 27 South Shanda Road, Jinan 250100, China
| | - Xin Xu
- School of Chemistry and Chemical
Engineering, Shandong University, No. 27 South Shanda Road, Jinan 250100, China
| | - Yingjie Zhao
- School of Chemistry and Chemical
Engineering, Shandong University, No. 27 South Shanda Road, Jinan 250100, China
| | - Jiong Jia
- School of Chemistry and Chemical
Engineering, Shandong University, No. 27 South Shanda Road, Jinan 250100, China
| | - Chen-Ho Tung
- School of Chemistry and Chemical
Engineering, Shandong University, No. 27 South Shanda Road, Jinan 250100, China
| | - Wenguang Wang
- School of Chemistry and Chemical
Engineering, Shandong University, No. 27 South Shanda Road, Jinan 250100, China
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5
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Wiedner ES, Chambers MB, Pitman CL, Bullock RM, Miller AJM, Appel AM. Thermodynamic Hydricity of Transition Metal Hydrides. Chem Rev 2016; 116:8655-92. [PMID: 27483171 DOI: 10.1021/acs.chemrev.6b00168] [Citation(s) in RCA: 298] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Transition metal hydrides play a critical role in stoichiometric and catalytic transformations. Knowledge of free energies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bond-breaking events that occur in a catalytic reaction. Thermodynamic hydricity is the free energy required to cleave an M-H bond to generate a hydride ion (H(-)). Three primary methods have been developed for hydricity determination: the hydride transfer method establishes hydride transfer equilibrium with a hydride donor/acceptor pair of known hydricity, the H2 heterolysis method involves measuring the equilibrium of heterolytic cleavage of H2 in the presence of a base, and the potential-pKa method considers stepwise transfer of a proton and two electrons to give a net hydride transfer. Using these methods, over 100 thermodynamic hydricity values for transition metal hydrides have been determined in acetonitrile or water. In acetonitrile, the hydricity of metal hydrides spans a range of more than 50 kcal/mol. Methods for using hydricity values to predict chemical reactivity are also discussed, including organic transformations, the reduction of CO2, and the production and oxidation of hydrogen.
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Affiliation(s)
- Eric S Wiedner
- Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Matthew B Chambers
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Catherine L Pitman
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - R Morris Bullock
- Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Alexander J M Miller
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Aaron M Appel
- Pacific Northwest National Laboratory , Richland, Washington 99352, United States
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6
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Koga K, Matsubara Y, Kosaka T, Koike K, Morimoto T, Ishitani O. Hydride Reduction of NAD(P)+ Model Compounds with a Ru(II)–Hydrido Complex. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00713] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kichitaro Koga
- Department of Chemistry,
Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
| | - Yasuo Matsubara
- Department
of Material and Life Chemistry, Kanagawa University, Rokkakubashi
3-27-1, Kanagawa-ku, Yokohama 221-8686, Japan
| | - Tatsumi Kosaka
- Graduate School of
Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Kazuhide Koike
- National Institute of Advanced Industrial Science and Technology, Onogawa 16-1, Tsukuba 305-8569, Japan
| | - Tatsuki Morimoto
- Department of Applied Chemistry, School of Engineering, Tokyo University of Technology, 1401-1 Katakura, Hachioji, Tokyo 192-0982, Japan
| | - Osamu Ishitani
- Department of Chemistry,
Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
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7
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Nakamura G, Kondo M, Crisalli M, Lee SK, Shibata A, Ford PC, Masaoka S. Syntheses and properties of phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides. Dalton Trans 2015; 44:17189-200. [DOI: 10.1039/c5dt02994e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The substitution lability of the nitrogen oxide ligands of novel phosphine-substituted ruthenium(ii) polypyridine complexes is discussed in comparison with that of the corresponding acetonitrile complexes.
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Affiliation(s)
- Go Nakamura
- Institute for Molecular Science (IMS)
- Okazaki
- Japan
- Department of Structural Molecular Science
- School of Physical Sciences
| | - Mio Kondo
- Institute for Molecular Science (IMS)
- Okazaki
- Japan
- Department of Structural Molecular Science
- School of Physical Sciences
| | - Meredith Crisalli
- Department of Chemistry and Biochemistry
- University of California at Santa Barbara
- Santa Barbara
- USA
| | - Sze Koon Lee
- Institute for Molecular Science (IMS)
- Okazaki
- Japan
| | | | - Peter C. Ford
- Department of Chemistry and Biochemistry
- University of California at Santa Barbara
- Santa Barbara
- USA
| | - Shigeyuki Masaoka
- Institute for Molecular Science (IMS)
- Okazaki
- Japan
- Department of Structural Molecular Science
- School of Physical Sciences
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8
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Nakamura G, Okamura M, Yoshida M, Suzuki T, Takagi HD, Kondo M, Masaoka S. Electrochemical Behavior of Phosphine-Substituted Ruthenium(II) Polypyridine Complexes with a Single Labile Ligand. Inorg Chem 2014; 53:7214-26. [DOI: 10.1021/ic5003644] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Go Nakamura
- Department of Structural Molecular Science,
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama-cho, Kanagawa 240-0193, Japan
- Institute for Molecular Science (IMS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Masaya Okamura
- Department of Structural Molecular Science,
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama-cho, Kanagawa 240-0193, Japan
- Institute for Molecular Science (IMS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Masaki Yoshida
- Institute for Molecular Science (IMS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Takayoshi Suzuki
- Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Hideo D. Takagi
- Graduate School of Science and Research Center
for Material Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Mio Kondo
- Department of Structural Molecular Science,
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama-cho, Kanagawa 240-0193, Japan
- Institute for Molecular Science (IMS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Research Center of Integrative Molecular Systems (CIMoS), 38 Nishigo-naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Japan Science and Technology Agency (JST), ACT-C, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Shigeyuki Masaoka
- Department of Structural Molecular Science,
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama-cho, Kanagawa 240-0193, Japan
- Institute for Molecular Science (IMS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Research Center of Integrative Molecular Systems (CIMoS), 38 Nishigo-naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
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9
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McSkimming A, Colbran SB. The coordination chemistry of organo-hydride donors: new prospects for efficient multi-electron reduction. Chem Soc Rev 2013; 42:5439-88. [PMID: 23507957 DOI: 10.1039/c3cs35466k] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In biological reduction processes the dihydronicotinamides NAD(P)H often transfer hydride to an unsaturated substrate bound within an enzyme active site. In many cases, metal ions in the active site bind, polarize and thereby activate the substrate to direct attack by hydride from NAD(P)H cofactor. This review looks more widely at the metal coordination chemistry of organic donors of hydride ion--organo-hydrides--such as dihydronicotinamides, other dihydropyridines including Hantzsch's ester and dihydroacridine derivatives, those derived from five-membered heterocycles including the benzimidazolines and benzoxazolines, and all-aliphatic hydride donors such as hexadiene and hexadienyl anion derivatives. The hydride donor properties--hydricities--of organo-hydrides and how these are affected by metal ions are discussed. The coordination chemistry of organo-hydrides is critically surveyed and the use of metal-organo-hydride systems in electrochemically-, photochemically- and chemically-driven reductions of unsaturated organic and inorganic (e.g. carbon dioxide) substrates is highlighted. The sustainable electrocatalytic, photochemical or chemical regeneration of organo-hydrides such as NAD(P)H, including for driving enzyme-catalysed reactions, is summarised and opportunities for development are indicated. Finally, new prospects are identified for metal-organo-hydride systems as catalysts for organic transformations involving 'hydride-borrowing' and for sustainable multi-electron reductions of unsaturated organic and inorganic substrates directly driven by electricity or light or by renewable reductants such as formate/formic acid.
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Affiliation(s)
- Alex McSkimming
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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10
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11
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Matsubara Y, Kosaka T, Koga K, Nagasawa A, Kobayashi A, Konno H, Creutz C, Sakamoto K, Ishitani O. Formation of η2-Coordinated Dihydropyridine–Ruthenium(II) Complexes by Hydride Transfer from Ruthenium(II) to Pyridinium Cations. Organometallics 2013. [DOI: 10.1021/om400862n] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yasuo Matsubara
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
- PRESTO, Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Tatsumi Kosaka
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Kichitaro Koga
- Department of Chemistry, Graduate School of
Science and Engineering, Tokyo Institute of Technology, O-okayama
2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
| | - Akira Nagasawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Atsuo Kobayashi
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Hideo Konno
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Carol Creutz
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Kazuhiko Sakamoto
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Osamu Ishitani
- Department of Chemistry, Graduate School of
Science and Engineering, Tokyo Institute of Technology, O-okayama
2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
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12
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Oppelt KT, Wöß E, Stiftinger M, Schöfberger W, Buchberger W, Knör G. Photocatalytic reduction of artificial and natural nucleotide co-factors with a chlorophyll-like tin-dihydroporphyrin sensitizer. Inorg Chem 2013; 52:11910-22. [PMID: 24073596 PMCID: PMC3805326 DOI: 10.1021/ic401611v] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
An
efficient photocatalytic two-electron reduction and protonation
of nicotine amide adenine dinucleotide (NAD+), as well
as the synthetic nucleotide co-factor analogue N-benzyl-3-carbamoyl-pyridinium
(BNAD+), powered by photons in the long-wavelength region
of visible light (λirr > 610 nm), is demonstrated
for the first time. This functional artificial photosynthetic counterpart
of the complete energy-trapping and solar-to-fuel conversion primary
processes occurring in natural photosystem I (PS I) is achieved with
a robust water-soluble tin(IV) complex of meso-tetrakis(N-methylpyridinium)-chlorin acting as the light-harvesting
sensitizer (threshold wavelength of λthr = 660 nm).
In buffered aqueous solution, this chlorophyll-like compound photocatalytically
recycles a rhodium hydride complex of the type [Cp*Rh(bpy)H]+, which is able to mediate regioselective hydride transfer processes.
Different one- and two-electron donors are tested for the reductive
quenching of the irradiated tin complex to initiate the secondary
dark reactions leading to nucleotide co-factor reduction. Very promising
conversion efficiencies, quantum yields, and excellent photosensitizer
stabilities are observed. As an example of a catalytic dark reaction
utilizing the reduction equivalents of accumulated NADH, an enzymatic
process for the selective transformation of aldehydes with alcohol
dehydrogenase (ADH) coupled to the primary photoreactions of the system
is also demonstrated. A tentative reaction mechanism for the transfer
of two electrons and one proton from the reductively quenched tin
chlorin sensitizer to the rhodium co-catalyst, acting as a reversible
hydride carrier, is proposed. An efficient photocatalytic
system for the two-electron
reduction of nucleotide co-factors has been characterized. For the
first time it could be demonstrated in an abiotic system that the
long-wavelength region of the visible spectrum (> 610 nm) can be
exploited
to power the accumulation of NADH. The artificial photosynthetic reaction
sequence, described here in detail, can be regarded as the first true
functional model system for the overall light reactions occurring
in natural photosystem I.
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Affiliation(s)
- Kerstin T Oppelt
- Institute of Inorganic Chemistry, and ‡Institute of Analytical Chemistry, Johannes Kepler University Linz (JKU) , A-4040 Linz, Austria
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13
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Matsubara Y, Fujita E, Doherty MD, Muckerman JT, Creutz C. Thermodynamic and Kinetic Hydricity of Ruthenium(II) Hydride Complexes. J Am Chem Soc 2012; 134:15743-57. [DOI: 10.1021/ja302937q] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yasuo Matsubara
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Etsuko Fujita
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Mark D. Doherty
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - James T. Muckerman
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Carol Creutz
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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14
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Padhi SK, Fukuda R, Ehara M, Tanaka K. Comparative study of C^N and N^C type cyclometalated ruthenium complexes with a NAD+/NADH function. Inorg Chem 2012; 51:8091-102. [PMID: 22827695 DOI: 10.1021/ic300449q] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cyclometalated ruthenium complexes having C(^)N and N(^)C type coordinating ligands with NAD(+)/NADH function have been synthesized and characterized by spectroscopic methods. The variation of the coordinating position of σ-donating carbon atom leads to a drastic change in their properties. Both the complex Ru(phbn)(phen)(2)]PF(6) ([1]PF(6)) and [Ru(pad)(phen)(2)]PF(6) ([2]PF(6)) reduced to Ru(phbnHH)(phen)(2)]PF(6) ([1HH]PF(6)) and [Ru(padHH)(phen)(2)]PF(6) ([2HH]PF(6)) by chemical and electrochemical methods. Complex [1]PF(6) photochemically reduced to [1HH]PF(6) in the presence of the sacrificial agent triethylamine (TEA) upon irradiation of visible light (λ ≥ 420 nm), whereas photochemical reduction of [2]PF(6) was not successful. Both experimental results and theoretical calculations reveal that upon protonation the energy level of the π* orbital of either of the ligands phbn or pad is drastically stabilized compared to the nonprotonated forms. In the protonated complex [Ru(padH)(phen)(2)](PF(6))(2) {[2H](PF(6))(2)}, the Ru-C bond exists in a tautomeric equilibrium with Ru═C coordination and behaves as a remote N-heterocyclic carbene (rNHC) compex; on the contrary, this behavior could not be observed in protonated complex [Ru(phbnH)(phen)(2)](PF(6))(2) {[1H](PF(6))(2)}.
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Affiliation(s)
- Sumanta Kumar Padhi
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1, Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
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15
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Padhi SK, Kobayashi K, Masuno S, Tanaka K. Proton-induced dynamic equilibrium between cyclometalated ruthenium rNHC (remote N-heterocyclic carbene) tautomers with an NAD+/NADH function. Inorg Chem 2011; 50:5321-3. [PMID: 21615114 DOI: 10.1021/ic200315f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclometalated ruthenium(II) complexes having acridine moieties have been synthesized and characterized by spectroscopic methods. Protonation of the acridine nitrogen of the ruthenium(II) complexes not only causes dynamic equilibrium with remote N-heterocyclic carbene Ru═C complexes but also generates the NAD(+)/NADH redox function driven by a proton-coupled two-electron transfer accompanying a reversible C-H bond formation in the pyridinium ring.
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Affiliation(s)
- Sumanta Kumar Padhi
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
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16
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Matsubara Y, Koga K, Kobayashi A, Konno H, Sakamoto K, Morimoto T, Ishitani O. Development of an efficient and durable photocatalytic system for hydride reduction of an NAD(P)+ model compound using a ruthenium(II) complex based on mechanistic studies. J Am Chem Soc 2010; 132:10547-52. [PMID: 20662527 DOI: 10.1021/ja1040122] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanism of photocatalytic reduction of 1-benzylnicotinamidium cation (BNA(+)) to the 1,4-dihydro form (1,4-BNAH) using [Ru(tpy)(bpy)(L)](2+) (Ru-L(2+), where tpy = 2,2':6',2''-terpyridine, bpy = 2,2'-bipyridine, and L = pyridine and MeCN) as a photocatalyst and NEt(3) as a reductant has been clarified. On the basis of this mechanistic study, an efficient and durable photocatalytic system for selective hydride reduction of an NAD(P)(+) model compound has been developed. The photocatalytic reaction is initiated by the formation of [Ru(tpy)(bpy)(NEt(3))](2+) (Ru-NEt(3)(2+)) via the photochemical ligand substitution of Ru-L(2+). For this reason, the production rate of 1,4-BNAH using [Ru(tpy)(bpy)(MeCN)](2+) (Ru-MeCN(2+)) as a photocatalyst, from which the quantum yield of photoelimination of the MeCN ligand is greater than that of the pyridine ligand from [Ru(tpy)(bpy)(pyridine)](2+) (Ru-py(2+)), was faster than that using Ru-py(2+), especially in the first stage of the photocatalytic reduction. The photoexcitation of Ru-NEt(3)(2+) yields [Ru(tpy)(bpy)H](+) (Ru-H(+)), which reacts with BNA(+) to give 1:1 adduct [Ru(tpy)(bpy)(1,4-BNAH)](2+) (Ru-BNAH(2+)). In the presence of excess NEt(3) in the reaction solution, a deprotonation of the carbamoyl group in Ru-BNAH(2+) proceeds rapidly, mainly forming [Ru(tpy)(bpy)(1,4-BNAH-H(+))](+) (Ru-(BNAH-H(+))(+)). Although photocleavage of the adduct yields 1,4-BNAH and the cycle is completed by the re-coordination of a NEt(3) molecule to the Ru(II) center, this process competes with hydride abstraction from Ru-(BNAH-H(+))(+) by BNA(+) giving 1,4-BNAH and [Ru(tpy)(bpy)(BNA(+)-H(+))](2+). This adduct was observed as the major complex in the reaction solution after the photocatalysis was depressed and is a dead-end product because of its stability. Based on the information about the reaction mechanism and the deactivation process, we have successfully developed a new photocatalytic system using Ru-MeCN(2+) with 2 M of NEt(3) as a reductant, which could reduce more than 59 equivalent amounts of an NAD(P)(+) model, 1-benzyl-N,N-diethylnicotinamidium cation, selectively to the corresponding 1,4-dihydro form in a 6 x 10(-4) quantum yield using 436-nm light.
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Affiliation(s)
- Yasuo Matsubara
- Department of Chemistry, Tokyo Institute of Technology, O-okayama 2-12-1, E1-9, Meguro-ku, Tokyo 152-8551, Japan
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Lee HM, Kim D, Singh NJ, Kołaski M, Kim KS. Hydrated hydride anion clusters. J Chem Phys 2007; 127:164311. [DOI: 10.1063/1.2778423] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kobayashi A, Konno H, Sakamoto K, Sekine A, Ohashi Y, Iida M, Ishitani O. Transition metal complexes coordinated by an NAD(P)H model compound and their enhanced hydride-donating abilities in the presence of a base. Chemistry 2006; 11:4219-26. [PMID: 15864798 DOI: 10.1002/chem.200401211] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ruthenium(II) and rhenium(I) complexes containing an NAD(P)H model compound, 1-benzyl-1,4-dihydronicotinamide (BNAH), as ligand, [Ru(tpy)(bpy)(BNAH)]2+ (1 a) and [Re(bpy)(CO)3(BNAH)]+ (1 b), were quantitatively produced by the reaction of the corresponding metal hydrido complexes with BNA(+) (1-benzylnicotinamidium cation). In the presence of base with pK(a) = 8.9, 1 a and 1 b have much greater reducing power than "free" BNAH. The oxidation potentials of 1 a in the absence and the presence of triethylamine were 0.55 V and -0.04 V, respectively, versus Ag/AgNO(3), whereas that of "free" BNAH was 0.30 V. Spectroscopic results clearly showed that the base extracts a proton from the carbamoyl group on 1 a and 1 b to give the deprotonated BNAH coordinating to the transition-metal complexes [Ru(tpy)(bpy)(BNAH-H+)]+ (3 a) and [Re(bpy)(CO)3(BNAH-H+)] (3 b); this deprotonation underlies the enhancement in reducing ability. The deprotonated forms 3 a and 3 b can efficiently reduce other NAD(P) models to give the corresponding 1,4-dihydro form, resulting in the deprotonated BNA+ being coordinated to the metal complexes [Ru(tpy)(bpy)(BNA(+)-H+)]2+ (2 a) and [Re(bpy)(CO)3(BNA+-H+)]+ (2 b); "free" BNAH and the protonated adducts 1 a and 1 b cannot act in this way. X-ray crystallography was performed on the PF6- salt of 2 a, and showed that the deprotonated nitrogen atom on the carbamoyl group coordinates to the ruthenium(II) metal center with a bond length of 2.086(3) Angstroms. Infrared spectral data suggested that the deprotonated carbamoyl group on the reduced forms 3 a and 3 b is converted to the imido group, and that the oxygen atom coordinates to the metal center.
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Affiliation(s)
- Atsuo Kobayashi
- Graduate School of Science and Engineering, Saitama University, Japan
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Kobayashi A, Sakamoto K, Ishitani O. Reaction of an NAD(P)+ model compound coordinated to a transition metal complex with ruthenium and rhenium hydrido complexes. INORG CHEM COMMUN 2005. [DOI: 10.1016/j.inoche.2005.01.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ellis WW, Ciancanelli R, Miller SM, Raebiger JW, Rakowski DuBois M, DuBois DL. Thermodynamic Hydride Donor Abilities of [HW(CO)4L]- Complexes (L = PPh3, P(OMe)3, CO) and Their Reactions with [C5Me5Re(PMe3)(NO)(CO)]+. J Am Chem Soc 2003; 125:12230-6. [PMID: 14519008 DOI: 10.1021/ja036524r] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The thermodynamic hydride donor abilities of [HW(CO)(5)](-) (40 kcal/mol), [HW(CO)(4)P(OMe(3))](-) (37 kcal/mol), and [HW(CO)(4)(PPh(3))](-) (36 kcal/mol) have been measured in acetonitrile by either equilibrium or calorimetric methods. The hydride donor abilities of these complexes are compared with other complexes for which similar thermodynamic measurements have been made. [HW(CO)(5)](-), [HW(CO)(4)P(OMe(3))](-), and [HW(CO)(4)(PPh(3))](-) all react rapidly with [CpRe(PMe(3))(NO)(CO)](+) to form dinuclear intermediates with bridging formyl ligands. These intermediates slowly form [CpRe(PMe(3))(NO)(CHO)] and [W(CO)(4)(L)(CH(3)CN)]. The structure of cis-[HW(CO)(4)(PPh(3))](-) has been determined and has the expected octahedral structure. The hydride ligand bends away from the CO ligand trans to PPh(3) and toward PPh(3).
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Affiliation(s)
- William W Ellis
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, USA
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Asplund MC, Snee PT, Yeston JS, Wilkens MJ, Payne CK, Yang H, Kotz KT, Frei H, Bergman RG, Harris CB. Ultrafast UV pump/IR probe studies of C-H activation in linear, cyclic, and aryl hydrocarbons. J Am Chem Soc 2002; 124:10605-12. [PMID: 12197763 DOI: 10.1021/ja020418s] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photochemical C-H activation reactions of eta(3)-TpRh(CO)(2) (Tp = HB-Pz(3), Pz = 3,5-dimethylpyrazolyl) and CpRh(CO)(2) (Cp = C(5)H(5)) have been studied in a series of linear, cyclic, and aromatic hydrocarbon solvents on a femtosecond to microsecond time scale. These results have revealed that the structure of the hydrocarbon substrate affects the final C-H bond activation step, which is in accordance with the known preference of bond activation toward primary C-H sites. In the case of aromatic C-H activation, the reaction is divided into parallel channels involving sigma- and pi-solvated intermediates. Results for the analogous CpRh(CO)(2) molecule have shown that the coordination of the cyclopentadienyl ligand does not play a direct role in the dynamics of the reaction, in contrast to the C-H activation mechanism observed in eta(3)-TpRh(CO)(2) studies.
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Affiliation(s)
- Matthew C Asplund
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Sellmann D, Prakash R, Geipel F, Heinemann F. Highly Soluble Sulfur-Rich [Ni(L)(siS3)] Complexes Containing the New Ligand Bis(2-mercapto-3-trimethylsilylphenyl) Sulfide(2−) (siS32−). Eur J Inorg Chem 2002. [DOI: 10.1002/1099-0682(200208)2002:8<2138::aid-ejic2138>3.0.co;2-h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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