1
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McCormick MJ, Machan CW. Developing homogeneous first row early transition metal catalysts for the oxygen reduction reaction. Dalton Trans 2024. [PMID: 39344902 DOI: 10.1039/d4dt01969e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
The oxygen reduction reaction (ORR) remains an important fixture in biological and synthetic systems for energy conversion and chemical functionalization. Late transition metals continue to dominate in the development of new catalyst systems, inspired by well-characterized metallocofactors and prior successes. By comparison, metals to the left of Fe on the periodic table are relatively understudied for the ORR. This Frontier article summarizes advancements related to the use of Mn, Cr, and V in homogeneous catalyst systems for the ORR and discusses the implications of these results for the development of catalyst systems from these metals and those earlier in the transition metal series.
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Affiliation(s)
- Mary Jo McCormick
- Department of Chemistry, University of Virginia, PO Box 400319, Charlottesville, VA 22904-4319, USA.
| | - Charles W Machan
- Department of Chemistry, University of Virginia, PO Box 400319, Charlottesville, VA 22904-4319, USA.
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2
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Pal K, Das D, Ghosh KG, Sureshkumar D. Visible-Light Driven Synthesis of Vinyl Amines without Photocatalyst. J Org Chem 2024. [PMID: 39326405 DOI: 10.1021/acs.joc.4c01624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2024]
Abstract
We developed a visible-light-induced vinyl amination of activated alkenes using TMSN3 and CsF through EDA complex formation under an oxygen atmosphere. Without light, the EDA complex forms between activated alkene, CsF, and oxygen. Upon exposure to light, oxygen in the complex gets excited, initiating the HAT process. This method efficiently synthesizes vinyl-amine derivatives via a radical pathway, demonstrating good functional group tolerance and high yields in a short time. Further, the late-stage functionalization enables the synthesis of biologically active heterocycles.
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Affiliation(s)
- Koustav Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
| | - Debabrata Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
| | - Krishna Gopal Ghosh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
| | - Devarajulu Sureshkumar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
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3
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Schneider JE, Zeng S, Anferov SW, Filatov AS, Anderson JS. Isolation and Crystallographic Characterization of an Octavalent Co 2O 2 Diamond Core. J Am Chem Soc 2024; 146:23998-24008. [PMID: 39146525 DOI: 10.1021/jacs.4c07335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
High-valent cobalt oxides play a pivotal role in alternative energy technology as catalysts for water splitting and as cathodes in lithium-ion batteries. Despite this importance, the properties governing the stability of high-valent cobalt oxides and specifically possible oxygen evolution pathways are not clear. One root of this limited understanding is the scarcity of high-valent Co(IV)-containing model complexes; there are no reports of stable, well-defined complexes with multiple Co(IV) centers. Here, an oxidatively robust fluorinated ligand scaffold enables the isolation and crystallographic characterization of a Co(IV)2-bis-μ-oxo complex. This complex is remarkably stable, in stark contrast with previously reported Co(IV)2 species that are highly reactive, which demonstrates that oxy-Co(IV)2 species are not necessarily unstable with respect to oxygen evolution. This example underscores a new design strategy for highly oxidizing transition-metal fragments and provides detailed data on a previously inaccessible chemical unit of relevance to O-O bond formation and oxygen evolution.
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Affiliation(s)
- Joseph E Schneider
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Shilin Zeng
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Sophie W Anferov
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Alexander S Filatov
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - John S Anderson
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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4
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Rademaker D, Tanase S, Kang H, Hofmann JP, Hetterscheid DGH. Selective Electrochemical Oxygen Reduction to Hydrogen Peroxide by Confinement of Cobalt Porphyrins in a Metal-Organic Framework. Chemistry 2024:e202401339. [PMID: 38872486 DOI: 10.1002/chem.202401339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/10/2024] [Accepted: 06/10/2024] [Indexed: 06/15/2024]
Abstract
Sustainable alternatives for the energy intensive synthesis of H2O2 are necessary. Molecular cobalt catalysts show potential but are typically restricted by undesired bimolecular pathways leading to the breakdown of both H2O2 and the catalyst. The confinement of cobalt porphyrins in the PCN-224 metal-organic framework leads to an enhanced selectivity towards H2O2 and stability of the catalyst. Consequently, oxygen can now be selectively reduced to hydrogen peroxide with a stable conversion for at least 5 h, illustrating the potential of catalysts confined in MOFs to increase the selectivity and stability of electrocatalytic conversions.
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Affiliation(s)
- Dana Rademaker
- Leiden Institute of Chemistry, Leiden University, 2300, RA Leiden, The Netherlands
| | - Stefania Tanase
- Van't Hoff Institute for Molecular Sciences, Universiteit van Amsterdam, 1098 XH, Amsterdam, The Netherlands
| | - Hongrui Kang
- Surface Science Laboratory Department of Materials- and Geosciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Jan P Hofmann
- Surface Science Laboratory Department of Materials- and Geosciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
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5
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Sarkar S, Tiwari RK, Samanta D, Guchhait T, Sañudo EC, Rajaraman G, Rath SP. Unusual Stabilisation of Remarkably Bent Tetra-Cationic Tetra-radical Intermolecular Fe(III) μ-Oxo Tetranuclear Complexes. Angew Chem Int Ed Engl 2024; 63:e202402344. [PMID: 38478415 DOI: 10.1002/anie.202402344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 04/24/2024]
Abstract
A hitherto unknown series of air stable, π-conjugated, remarkably bent tetra-cation tetra-radical intermolecular Fe(III) μ-oxo tetranuclear complex, isolated from the dication diradical diiron(III) porphyrin dimers, has been synthesised and spectroscopically characterised along with single crystal X-ray structure determination of two such molecules. These species facilitate long-range charge/radical delocalisation through the bridge across the entire tetranuclear unit manifesting an unusually intense NIR band. Assorted spin states of Fe(III) centres are stabilised within these unique tetranuclear frameworks: terminal six-coordinate iron centres stabilise the admixed intermediate spin states while the central five-coordinate iron centres stabilise the high-spin states. Variable temperature magnetic susceptibility measurements indicated strong antiferromagnetic coupling for the Fe(III)-O-Fe(III) unit while the exchange interactions between the Fe centres and the porphyrin π-cation radicals are weaker as supported both by magnetic data and DFT calculations. The nature of orbital overlap between the SOMOs of Fe(III) and π* orbital of the porphyrin was found to rationalise the observed exchange coupling, establishing such a complex magnetic exchange in this tetranuclear model with a significant bioinorganic relevance.
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Affiliation(s)
- Sabyasachi Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Rupesh Kumar Tiwari
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Deepannita Samanta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Tapas Guchhait
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - E Carolina Sañudo
- Secció de Química Inorgànica, Department de Química Inorgànica i Orgànica, Facultat de Química, Universitat de Barcelona, C/Martí i Franqués 1-11, 08028, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia, IN2UB, Universitat de Barcelona, C/Martí i Franqués 1-11, 08028, Barcelona, Spain
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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6
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Wei J, Meng J, Zhang C, Liu Y, Jiao N. Dioxygen compatible electron donor-acceptor catalytic system and its enabled aerobic oxygenation. Nat Commun 2024; 15:1886. [PMID: 38424055 PMCID: PMC10904740 DOI: 10.1038/s41467-024-45866-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024] Open
Abstract
The photochemical properties of Electron Donor-Acceptor (EDA) complexes present exciting opportunities for synthetic chemistry. However, these strategies often require an inert atmosphere to maintain high efficiency. Herein, we develop an EDA complex photocatalytic system through rational design, which overcomes the oxygen-sensitive limitation of traditional EDA photocatalytic systems and enables aerobic oxygenation reactions through dioxygen activation. The mild oxidation system transfers electrons from the donor to the effective catalytic acceptor upon visible light irradiation, which are subsequently captured by molecular oxygen to form the superoxide radical ion, as demonstrated by the specific fluorescent probe, dihydroethidine (DHE). Furthermore, this visible-light mediated oxidative EDA protocol is successfully applied in the aerobic oxygenation of boronic acids. We believe that this photochemical dioxygen activation strategy enabled by EDA complex not only provides a practical approach to aerobic oxygenation but also promotes the design and application of EDA photocatalysis under ambient conditions.
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Affiliation(s)
- Jialiang Wei
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 100191, Beijing, China
- Changping Laboratory, Yard 28, Science Park Road, Changping District, 102206, Beijing, China
| | - Junhong Meng
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 100191, Beijing, China
| | - Caifang Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 100191, Beijing, China
| | - Yameng Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 100191, Beijing, China
| | - Ning Jiao
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 100191, Beijing, China.
- Changping Laboratory, Yard 28, Science Park Road, Changping District, 102206, Beijing, China.
- State Key Laboratory of Organometallic Chemistry Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
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7
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Lionetti D, Suseno S, Shiau AA, de Ruiter G, Agapie T. Redox Processes Involving Oxygen: The Surprising Influence of Redox-Inactive Lewis Acids. JACS AU 2024; 4:344-368. [PMID: 38425928 PMCID: PMC10900226 DOI: 10.1021/jacsau.3c00675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 03/02/2024]
Abstract
Metalloenzymes with heteromultimetallic active sites perform chemical reactions that control several biogeochemical cycles. Transformations catalyzed by such enzymes include dioxygen generation and reduction, dinitrogen reduction, and carbon dioxide reduction-instrumental transformations for progress in the context of artificial photosynthesis and sustainable fertilizer production. While the roles of the respective metals are of interest in all these enzymatic transformations, they share a common factor in the transfer of one or multiple redox equivalents. In light of this feature, it is surprising to find that incorporation of redox-inactive metals into the active site of such an enzyme is critical to its function. To illustrate, the presence of a redox-inactive Ca2+ center is crucial in the Oxygen Evolving Complex, and yet particularly intriguing given that the transformation catalyzed by this cluster is a redox process involving four electrons. Therefore, the effects of redox inactive metals on redox processes-electron transfer, oxygen- and hydrogen-atom transfer, and O-O bond cleavage and formation reactions-mediated by transition metals have been studied extensively. Significant effects of redox inactive metals have been observed on these redox transformations; linear free energy correlations between Lewis acidity and the redox properties of synthetic model complexes are observed for several reactions. In this Perspective, these effects and their relevance to multielectron processes will be discussed.
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Affiliation(s)
| | - Sandy Suseno
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
| | - Angela A. Shiau
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
| | - Graham de Ruiter
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
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8
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Nayek A, Dey S, Patra S, Rana A, Serrano PN, George SJ, Cramer SP, Ghosh Dey S, Dey A. Facile electrocatalytic proton reduction by a [Fe-Fe]-hydrogenase bio-inspired synthetic model bearing a terminal CN - ligand. Chem Sci 2024; 15:2167-2180. [PMID: 38332837 PMCID: PMC10848691 DOI: 10.1039/d3sc05397k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 12/22/2023] [Indexed: 02/10/2024] Open
Abstract
An azadithiolate bridged CN- bound pentacarbonyl bis-iron complex, mimicking the active site of [Fe-Fe] H2ase is synthesized. The geometric and electronic structure of this complex is elucidated using a combination of EXAFS analysis, infrared and Mössbauer spectroscopy and DFT calculations. The electrochemical investigations show that complex 1 effectively reduces H+ to H2 between pH 0-3 at diffusion-controlled rates (1011 M-1 s-1) i.e. 108 s-1 at pH 3 with an overpotential of 140 mV. Electrochemical analysis and DFT calculations suggests that a CN- ligand increases the pKa of the cluster enabling hydrogen production from its Fe(i)-Fe(0) state at pHs much higher and overpotential much lower than its precursor bis-iron hexacarbonyl model which is active in its Fe(0)-Fe(0) state. The formation of a terminal Fe-H species, evidenced by spectroelectrochemistry in organic solvent, via a rate determining proton coupled electron transfer step and protonation of the adjacent azadithiolate, lowers the kinetic barrier leading to diffusion controlled rates of H2 evolution. The stereo-electronic factors enhance its catalytic rate by 3 order of magnitude relative to a bis-iron hexacarbonyl precursor at the same pH and potential.
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Affiliation(s)
- Abhijit Nayek
- School of Chemical Science, Indian Association for the Cultivation of Science Kolkata 700032 India
| | - Subal Dey
- School of Chemical Science, Indian Association for the Cultivation of Science Kolkata 700032 India
| | - Suman Patra
- School of Chemical Science, Indian Association for the Cultivation of Science Kolkata 700032 India
| | - Atanu Rana
- School of Chemical Science, Indian Association for the Cultivation of Science Kolkata 700032 India
| | - Pauline N Serrano
- Department of Chemistry, University of California Davis CA 94616 USA
| | - Simon J George
- Department of Chemistry, University of California Davis CA 94616 USA
- SETI Institute 339 Bernardo Ave, Suite, 200 Mountain View CA 94043 USA
| | - Stephen P Cramer
- Department of Chemistry, University of California Davis CA 94616 USA
- Physical Biosciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
- SETI Institute 339 Bernardo Ave, Suite, 200 Mountain View CA 94043 USA
| | - Somdatta Ghosh Dey
- School of Chemical Science, Indian Association for the Cultivation of Science Kolkata 700032 India
| | - Abhishek Dey
- School of Chemical Science, Indian Association for the Cultivation of Science Kolkata 700032 India
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9
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Meyer Q, Yang C, Cheng Y, Zhao C. Overcoming the Electrode Challenges of High-Temperature Proton Exchange Membrane Fuel Cells. ELECTROCHEM ENERGY R 2023. [DOI: 10.1007/s41918-023-00180-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
AbstractProton exchange membrane fuel cells (PEMFCs) are becoming a major part of a greener and more sustainable future. However, the costs of high-purity hydrogen and noble metal catalysts alongside the complexity of the PEMFC system severely hamper their commercialization. Operating PEMFCs at high temperatures (HT-PEMFCs, above 120 °C) brings several advantages, such as increased tolerance to contaminants, more affordable catalysts, and operations without liquid water, hence considerably simplifying the system. While recent progresses in proton exchange membranes for HT-PEMFCs have made this technology more viable, the HT-PEMFC viscous acid electrolyte lowers the active site utilization by unevenly diffusing into the catalyst layer while it acutely poisons the catalytic sites. In recent years, the synthesis of platinum group metal (PGM) and PGM-free catalysts with higher acid tolerance and phosphate-promoted oxygen reduction reaction, in conjunction with the design of catalyst layers with improved acid distribution and more triple-phase boundaries, has provided great opportunities for more efficient HT-PEMFCs. The progress in these two interconnected fields is reviewed here, with recommendations for the most promising routes worthy of further investigation. Using these approaches, the performance and durability of HT-PEMFCs will be significantly improved.
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10
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Zhang HT, Xie F, Guo YH, Xiao Y, Zhang MT. Selective Four-Electron Reduction of Oxygen by a Nonheme Heterobimetallic CuFe Complex. Angew Chem Int Ed Engl 2023; 62:e202310775. [PMID: 37837365 DOI: 10.1002/anie.202310775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/16/2023]
Abstract
We report herein the first nonheme CuFe oxygen reduction catalyst ([CuII (bpbp)(μ-OAc)2 FeIII ]2+ , CuFe-OAc), which serves as a functional model of cytochrome c oxidase and can catalyze oxygen reduction to water with a turnover frequency of 2.4×103 s-1 and selectivity of 96.0 % in the presence of Et3 NH+ . This performance significantly outcompetes its homobimetallic analogues (2.7 s-1 of CuCu-OAc with %H2 O2 selectivity of 98.9 %, and inactive of FeFe-OAc) under the same conditions. Structure-activity relationship studies, in combination with density functional theory calculation, show that the CuFe center efficiently mediates O-O bond cleavage via a CuII (μ-η1 : η2 -O2 )FeIII peroxo intermediate in which the peroxo ligand possesses distinctive coordinating and electronic character. Our work sheds light on the nature of Cu/Fe heterobimetallic cooperation in oxygen reduction catalysis and demonstrates the potential of this synergistic effect in the design of nonheme oxygen reduction catalysts.
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Affiliation(s)
- Hong-Tao Zhang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Fei Xie
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yu-Hua Guo
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yao Xiao
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Ming-Tian Zhang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
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11
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Uchida T. Development of Catalytic Site-Selective C-H Oxidation. CHEM REC 2023; 23:e202300156. [PMID: 37350373 DOI: 10.1002/tcr.202300156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/05/2023] [Indexed: 06/24/2023]
Abstract
Direct C-H bond oxygenation is a strong and useful tool for the construction of oxygen functional groups. After Chen and White's pioneering works, various non-heme-type iron and manganese complexes were introduced, leading to strong development in this area. However, for this method to become a truly useful tool for synthetic organic chemistry, it is necessary to make further efforts to improve site-selectivity, and catalyst durability. Recently, we found that non-heme-type ruthenium complex cis-1 presents efficient catalysis in C(sp3 )-H oxygenation under acidic conditions. cis-1-catalysed C-H oxygenation can oxidize various substrates including highly complex natural compounds using hypervalent iodine reagents as a terminal oxidant. Moreover, the catalyst system can use almost stoichiometric water molecules as the oxygen source through reversible hydrolysis of PhI(OCOR)2 . It is a strong tool for producing isotopic-oxygen-labelled compounds. Moreover, the environmentally friendly hydrogen peroxide can be used as a terminal oxidant under acidic conditions.
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Affiliation(s)
- Tatsuya Uchida
- Faculty of Arts and Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
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12
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Jiang YY, Chen C. Recent advances in computational studies on Cu-catalyzed aerobic reactions: cooperation of copper catalysts and dioxygen. Org Biomol Chem 2023; 21:7852-7872. [PMID: 37725071 DOI: 10.1039/d3ob00976a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
O2, one of the ideal oxidants, suffers from low solubility, low oxidizability, low selectivity and a triplet ground state when applied in organic synthesis. Biomimetic copper catalysis has been demonstrated to be a powerful method for activating and transforming O2 to conduct aerobic reactions for a long time. On the other hand, the structures of Cu-O2 complexes are complex with diverse downstream reactions, whereas active copper intermediates were rarely identified by experimental methods, making the mechanisms of many Cu-catalyzed aerobic reactions far from clear. In this context, computational studies emerged as an effective alternative to mechanistic studies on Cu-catalyzed aerobic reactions. This review introduces the relevant computational studies since 2012, focusing on showing the cooperation of copper catalysts and O2 in dehydrogenation, oxygenation and coupling reactions.
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Affiliation(s)
- Yuan-Ye Jiang
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, People's Republic of China.
| | - Chao Chen
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, People's Republic of China.
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13
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Hwang D, Wrigley LM, Lee M, Sobolewski AL, Domcke W, Schlenker CW. Local Hydrogen Bonding Determines Branching Pathways in Intermolecular Heptazine Photochemistry. J Phys Chem B 2023. [PMID: 37471476 DOI: 10.1021/acs.jpcb.3c01397] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Heptazine is the molecular core of the widely studied photocatalyst carbon nitride. By analyzing the excited-state intermolecular proton-coupled electron-transfer (PCET) reaction between a heptazine derivative and a hydrogen-atom donor substrate, we are able to spectroscopically identify the resultant heptazinyl reactive radical species on a picosecond time scale. We provide detailed spectroscopic characterization of the tri-anisole heptazine:4-methoxyphenol hydrogen-bonded intermolecular complex (TAHz:MeOPhOH), using femtosecond transient absorption spectroscopy and global analysis, to reveal distinct product absorption signatures at ∼520, 1250, and 1600 nm. We assign these product peaks to the hydrogenated TAHz radical (TAHzH•) based on control experiments utilizing 1,4-dimethoxybenzene (DMB), which initiates electron transfer without concomitant proton transfer, i.e., no excited-state PCET. Additional control experiments with radical quenchers, protonation agents, and UV-vis-NIR spectroelectrochemistry also corroborate our product peak assignments. These spectral assignments allowed us to monitor the influence of the local hydrogen-bonding environment on the resulting evolution of photochemical products from excited-state PCET of heptazines. We observe that the preassociation of heptazine with the substrate in solution is extremely sensitive to the hydrogen-bond-accepting character of the solvent. This sensitivity directly influences which product signatures we detect with time-resolved spectroscopy. The spectral signature of the TAHzH• radical assigned in this work will facilitate future in-depth analysis of heptazine and carbon nitride photochemistry. Our results may also be utilized for designing improved PCET-based photochemical systems that will require precise control over local molecular environments. Examples include applications such as preparative synthesis involving organic photoredox catalysis, on-site solar water purification, as well as photocatalytic water splitting and artificial photosynthesis.
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Affiliation(s)
- Doyk Hwang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Liam M Wrigley
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Micah Lee
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | | | - Wolfgang Domcke
- Department of Chemistry, Technical University of Munich, D-85747 Garching, Germany
| | - Cody W Schlenker
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Molecular Engineering & Sciences Institute, University of Washington, Seattle, Washington 98195-1652, United States
- Clean Energy Institute, University of Washington, Seattle, Washington 98195-1653, United States
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14
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Franceschi P, Rossin E, Goti G, Scopano A, Vega-Peñaloza A, Natali M, Singh D, Sartorel A, Dell'Amico L. A Proton-Coupled Electron Transfer Strategy to the Redox-Neutral Photocatalytic CO 2 Fixation. J Org Chem 2023; 88:6454-6464. [PMID: 36760023 DOI: 10.1021/acs.joc.2c02952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Herein, we report our study on the design and development of a novel photocarboxylation method. We have used an organic photoredox catalyst (PC, 4CzIPN) and differently substituted dihydropyridines (DHPs) in combination with an organic base (1,5,7-triazabicyclodec-5-ene, TBD) to access a proton-coupled electron transfer (PCET) based manifold. In depth mechanistic investigations merging experimental analysis (NMR, IR, cyclic voltammetry) and density-functional theory (DFT) calculations reveal the key activity of a H-bonding complex between the DHP and the base. The thermodynamic and kinetic benefits of the PCET mechanism allowed the implementation of a redox-neutral fixation process leading to synthetically relevant carboxylic acids (18 examples with isolated yields up to 75%) under very mild reaction conditions. Finally, diverse product manipulations were performed to demonstrate the synthetic versatility of the obtained products.
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Affiliation(s)
- Pietro Franceschi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Elena Rossin
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Giulio Goti
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Angelo Scopano
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Alberto Vega-Peñaloza
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Mirco Natali
- Department of Chemical, Pharmaceutical, and Agricultural Sciences, University of Ferrara, Via L. Borsari 46, 44121 Ferrara, Italy
| | - Deepak Singh
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Andrea Sartorel
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Luca Dell'Amico
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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15
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Zhang D, Crawley MR, Oldacre AN, Kyle LJ, MacMillan SN, Cook TR. Lowering the Symmetry of Cofacial Porphyrin Prisms for Selective Oxygen Reduction Electrocatalysis. Inorg Chem 2023; 62:1766-1775. [PMID: 35699516 DOI: 10.1021/acs.inorgchem.2c01109] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cofacial porphyrin catalysts for the Oxygen Reduction Reaction (ORR) formed via coordination-driven self-assembly have so far been limited to designs with fourfold symmetry, where four molecular clips bridge two porphyrin sites. We have synthesized six PynPhm (Py = pyridyl, Ph = phenyl) metalloporphyrin prisms (Co2+, Zn2+) bridged by molecular clips containing two Rh3+ centers. Four of these structures are lower symmetry, with the Py3Ph and Py2Ph2 prisms containing three and two molecular clips, respectively. The Co2+ species were evaluated for their ORR activity. Cyclic and hydrodynamic voltammetry studies of heterogeneous catalyst inks in aqueous media revealed marked differences in selectivity from ∼5% (Py3Ph) to ∼37% (Py2Ph2) for the formation of H2O2. The single-crystal X-ray structure of the Zn2 Py2Ph2 prism shows an offset between the porphyrin faces. This structural feature may be responsible for the change in selectivity, consistent with previous studies of covalently tethered cofacial porphyrins that have shown that geometry is a critical determinant of two-electron/two-proton versus four-electron/four-proton pathways. Extraction of standard rate constants ks for the ORR revealed a cofacial enhancement of ∼2 orders of magnitude over mononuclear Co2+ tetrapyridyl porphyrin. Even though all the prisms described here use the same molecular clip, the resultant structures, and thus the reactivity for the ORR, differ significantly based on the number and orientation of pyridyl donor groups on the porphyrins, highlighting how coordination-driven self-assembly can be used to rapidly tune dinuclear catalysts.
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Affiliation(s)
- Daoyang Zhang
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Matthew R Crawley
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Amanda N Oldacre
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Lea J Kyle
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Timothy R Cook
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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16
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Battistella B, Iffland-Mühlhaus L, Schütze M, Cula B, Kuhlmann U, Dau H, Hildebrandt P, Lohmiller T, Mebs S, Apfel UP, Ray K. Evidence of Sulfur Non-Innocence in [Co II (dithiacyclam)] 2+ -Mediated Catalytic Oxygen Reduction Reactions. Angew Chem Int Ed Engl 2023; 62:e202214074. [PMID: 36378951 PMCID: PMC10108118 DOI: 10.1002/anie.202214074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/16/2022]
Abstract
In many metalloenzymes, sulfur-containing ligands participate in catalytic processes, mainly via the involvement in electron transfer reactions. In a biomimetic approach, we now demonstrate the implication of S-ligation in cobalt mediated oxygen reduction reactions (ORR). A comparative study between the catalytic ORR capabilities of the four-nitrogen bound [Co(cyclam)]2+ (1; cyclam=1,5,8,11-tetraaza-cyclotetradecane) and the S-containing analog [Co(S2 N2 -cyclam)]2+ (2; S2 N2 -cyclam=1,8-dithia-5,11-diaza-cyclotetradecane) reveals improved catalytic performance once the chalcogen is introduced in the Co coordination sphere. Trapping and characterization of the intermediates formed upon dioxygen activation at the CoII centers in 1 and 2 point to the involvement of sulfur in the O2 reduction process as the key for the improved catalytic ORR capabilities of 2.
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Affiliation(s)
- Beatrice Battistella
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Linda Iffland-Mühlhaus
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Maximillian Schütze
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Dau
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Lohmiller
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany
| | - Stefan Mebs
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany.,Department for Electrosynthesis, Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047, Oberhausen, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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17
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Underhill J, Yang ES, Schmidt‐Räntsch T, Myers WK, Goicoechea JM, Abbenseth J. Dioxygen Splitting by a Tantalum(V) Complex Ligated by a Rigid, Redox Non-Innocent Pincer Ligand. Chemistry 2023; 29:e202203266. [PMID: 36281622 PMCID: PMC10098518 DOI: 10.1002/chem.202203266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Indexed: 12/05/2022]
Abstract
The reaction of TaMe3 Cl2 with the rigid acridane-derived trisamine H3 NNN yields the tantalum(V) complex [TaCl2 (NNNcat )]. Subsequent reaction with dioxygen results in the full four-electron reduction of O2 yielding the oxido-bridged bimetallic complex [{TaCl2 (NNNsq )}2 O]. This dinuclear complex features an open-shell ground state due to partial ligand oxidation and was comprehensively characterized by single crystal X-ray diffraction, LIFDI mass spectrometry, NMR, EPR, IR and UV/VIS/NIR spectroscopy. The mechanism of O2 activation was investigated by DFT calculations revealing initial binding of O2 to the tantalum(V) center followed by complete O2 scission to produce a terminal oxido-complex.
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Affiliation(s)
- Jack Underhill
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield Rd.OxfordOX1 3TAUnited Kingdom
| | - Eric S. Yang
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield Rd.OxfordOX1 3TAUnited Kingdom
| | - Till Schmidt‐Räntsch
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstraße 437077GöttingenGermany
| | - William K. Myers
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield Rd.OxfordOX1 3TAUnited Kingdom
| | - Jose M. Goicoechea
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield Rd.OxfordOX1 3TAUnited Kingdom
| | - Josh Abbenseth
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield Rd.OxfordOX1 3TAUnited Kingdom
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18
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Pandit YA, Usman M, Sarkar A, Shah SJ, Rath SP. Control of spin coupling through a redox-active bridge in a dinickel(II) porphyrin dimer: step-wise oxidations enable isolations of a chlorin-porphyrin heterodimer and a dication diradical with a singlet ground state. Dalton Trans 2023; 52:877-891. [PMID: 36464989 DOI: 10.1039/d2dt03283j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A dinickel(II)porphyrin dimer has been used here in which the redox-active pyrrole-moiety, similar to the tryptophan residue in diheme enzymes such as MauG and bCcP, has been placed between two Ni(II)porphyrin centers connected via a flexible, but unconjugated methylene bridge. This arrangement provides a large physical separation between the two metal centers and thus displays almost no communication between them through the bridge. Upon treatment with DDQ as an oxidant, the dinickel(II) porphyrin dimer slowly gets converted into an indolizinium-fused chlorin-porphyrin heterodimer. However, oxidations of the dinickel(II) porphyrin dimer up to two oxidizing equivalents using oxidants such as AgSbF6 and FeCl3 resulted in the formation of a dication diradical complex. Interestingly, in order to stabilize such a highly oxidized dication diradical, two non-conjugated methylene spacers undergo facile 2e-/-2H+ oxidation to make the bridge fully π-conjugated for promoting through-bond communication. Through the oxidized and conjugated bridge, two porphyrin π-cation radicals display considerable communications leading to an efficient intramolecular spin coupling to form a singlet state. Interestingly, the redox-active nature of the bridge controls the electronic communication just by simple oxidation or reduction, and thereby, acts as a molecular switch for efficient magnetic relay.
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Affiliation(s)
- Younis Ahmad Pandit
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Anindya Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Syed Jehanger Shah
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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19
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Zhang D, Crawley MR, Fang M, Kyle LJ, Cook TR. The rigidity of self-assembled cofacial porphyrins influences selectivity and kinetics of oxygen reduction electrocatalysis. Dalton Trans 2022; 51:18373-18377. [PMID: 36411983 DOI: 10.1039/d2dt02724k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We report the electrocatalytic Oxygen Reduction Reaction on a rigid Co(II) porphyrin prism scaffold bridged by Ag(I) ions. The reactivity of this scaffold differs significantly from previous prism catalysts in that its selectivity is similar to that of monomer (∼35% H2O) yet it displays sluggish kinetics, with an order of magnitude lower ks of ∼0.5 M-1 s-1. The deleterious cofacial effect is not simply due to metal-metal separation, which is similar to our most selective prism catalysts. Instead we conclude the structural rigidity is responsible for these differences.
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Affiliation(s)
- Daoyang Zhang
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA.
| | - Matthew R Crawley
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA.
| | - Ming Fang
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA.
| | - Lea J Kyle
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA.
| | - Timothy R Cook
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA.
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20
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Iacobini C, Vitale M, Haxhi J, Pesce C, Pugliese G, Menini S. Mutual Regulation between Redox and Hypoxia-Inducible Factors in Cardiovascular and Renal Complications of Diabetes. Antioxidants (Basel) 2022; 11:2183. [PMID: 36358555 PMCID: PMC9686572 DOI: 10.3390/antiox11112183] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 08/30/2023] Open
Abstract
Oxidative stress and hypoxia-inducible factors (HIFs) have been implicated in the pathogenesis of diabetic cardiovascular and renal diseases. Reactive oxygen species (ROS) mediate physiological and pathophysiological processes, being involved in the modulation of cell signaling, differentiation, and survival, but also in cyto- and genotoxic damage. As master regulators of glycolytic metabolism and oxygen homeostasis, HIFs have been largely studied for their role in cell survival in hypoxic conditions. However, in addition to hypoxia, other stimuli can regulate HIFs stability and transcriptional activity, even in normoxic conditions. Among these, a regulatory role of ROS and their byproducts on HIFs, particularly the HIF-1α isoform, has received growing attention in recent years. On the other hand, HIF-1α and HIF-2α exert mutually antagonistic effects on oxidative damage. In diabetes, redox-mediated HIF-1α deregulation contributes to the onset and progression of cardiovascular and renal complications, and recent findings suggest that deranged HIF signaling induced by hyperglycemia and other cellular stressors associated with metabolic disorders may cause mitochondrial dysfunction, oxidative stress, and inflammation. Understanding the mechanisms of mutual regulation between HIFs and redox factors and the specific contribution of the two main isoforms of HIF-α is fundamental to identify new therapeutic targets for vascular complications of diabetes.
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Affiliation(s)
- Carla Iacobini
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy
| | - Martina Vitale
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy
| | - Jonida Haxhi
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy
| | - Carlo Pesce
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and Maternal Infantile Sciences (DINOGMI), Department of Excellence of MIUR, University of Genoa Medical School, 16132 Genoa, Italy
| | - Giuseppe Pugliese
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy
| | - Stefano Menini
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy
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21
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Palladium complexes bearing calixpyrrole ligands with pendant hydrogen bond donors: Synthesis, structural characterization, electrochemistry and dihydrogen evolution. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.116046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Kumar A, Zhang G, Liu W, Sun X. Electrocatalysis and activity descriptors with metal phthalocyanines for energy conversion reactions. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Wei Y, Zhao L, Yuan R, Xue Z, Mack J, Chiyumba C, Nyokong T, Zhang J. Promotion of Catalytic Oxygen Reduction Reactions: The Utility of Proton Management Substituents on Cobalt Porphyrins. Inorg Chem 2022; 61:13085-13095. [PMID: 35943152 DOI: 10.1021/acs.inorgchem.2c01591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Three ABAB-type cobalt meso-tetraarylporphyrins with fluorine (F-CoPor), acetic acid (AC-CoPor), and cyanoacetic acid (CN-CoPor) groups at the para-positions of phenyl rings at the 10,20-positions are synthesized and evaluated as catalysts for oxygen reduction reactions (ORRs). In density functional theory calculations, the frontier molecular orbitals of these complexes were found to be stabilized relative to model complexes with electron-withdrawing atoms or moieties on the meso-aryl rings. Electrochemical measurements suggest that electrodes with CN-CoPor (CN-CoPor/C) exhibit the most positive ORR potential values and the highest limiting current density in both acidic and alkali electrolytes, while the F-CoPor/C electrocatalyst exhibits extremely low ORR performance. The electron transfer numbers for the electrocatalysts are more than 3.0, indicating that a mixture of 2- and 4-electron transfer pathways occurs. The results demonstrate that coupling the hydrogen bonding properties and electron-withdrawing abilities through rational design of the substituent at the meso-position is an efficient way to modify the ORR performance.
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Affiliation(s)
- Yuqin Wei
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Long Zhao
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Rui Yuan
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Zhaoli Xue
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - John Mack
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, Makhanda 6140, South Africa
| | - Choonzo Chiyumba
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, Makhanda 6140, South Africa
| | - Tebello Nyokong
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, Makhanda 6140, South Africa
| | - Jianming Zhang
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
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24
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Ghatak A, Samanta S, Nayek A, Mukherjee S, Dey SG, Dey A. Second-Sphere Hydrogen-Bond Donors and Acceptors Affect the Rate and Selectivity of Electrochemical Oxygen Reduction by Iron Porphyrins Differently. Inorg Chem 2022; 61:12931-12947. [PMID: 35939766 DOI: 10.1021/acs.inorgchem.2c02170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The factors that control the rate and selectivity of 4e-/4H+ O2 reduction are important for efficient energy transformation as well as for understanding the terminal step of respiration in aerobic organisms. Inspired by the design of naturally occurring enzymes which are efficient catalysts for O2 and H2O2 reduction, several artificial systems have been generated where different second-sphere residues have been installed to enhance the rate and efficiency of the 4e-/4H+ O2 reduction. These include hydrogen-bonding residues like amines, carboxylates, ethers, amides, phenols, etc. In some cases, improvements in the catalysis were recorded, whereas in some cases improvements were marginal or nonexistent. In this work, we use an iron porphyrin complex with pendant 1,10-phenanthroline residues which show a pH-dependent variation of the rate of the electrochemical O2 reduction reaction (ORR) over 2 orders of magnitude. In-situ surface-enhanced resonance Raman spectroscopy reveals the presence of different intermediates at different pH's reflecting different rate-determining steps at different pH's. These data in conjunction with density functional theory calculations reveal that when the distal 1,10-phenanthroline is neutral it acts as a hydrogen-bond acceptor which stabilizes H2O (product) binding to the active FeII state and retards the reaction. However, when the 1,10-phenanthroline is protonated, it acts as a hydrogen-bond donor which enhances O2 reduction by stabilizing FeIII-O2.- and FeIII-OOH intermediates and activating the O-O bond for cleavage. On the basis of these data, general guidelines for controlling the different possible rate-determining steps in the complex multistep 4e-/4H+ ORR are developed and a bioinspired principle-based design of an efficient electrochemical ORR is presented.
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Affiliation(s)
- Arnab Ghatak
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, West Bengal 700032, India
| | - Soumya Samanta
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, West Bengal 700032, India
| | - Abhijit Nayek
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, West Bengal 700032, India
| | - Sudipta Mukherjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, West Bengal 700032, India
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, West Bengal 700032, India
| | - Abhishek Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, West Bengal 700032, India
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25
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Tabaru K, Obora Y. Synergic Palladium Catalysis for Aerobic Oxidative Coupling. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kazuki Tabaru
- Kansai University: Kansai Daigaku Department of Chemistry and Materials Engineering 3-3-35 Yamate-cho 564-8680 Suita JAPAN
| | - Yasushi Obora
- Kansai University: Kansai Daigaku Department of Chemistry and Materials Engineering 3-3-35 Yamate-cho 564-8680 Suita JAPAN
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26
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Jiang C, Miao J, Zhang D, Wen Z, Yang C, Li K. Acceptor-Donor-Acceptor π-Stacking Boosts Intramolecular Through-Space Charge Transfer towards Efficient Red TADF and High-Performance OLEDs. Research (Wash D C) 2022; 2022:9892802. [PMID: 35935129 PMCID: PMC9275096 DOI: 10.34133/2022/9892802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 06/01/2022] [Indexed: 11/18/2022] Open
Abstract
Organic push-pull systems featuring through-space charge transfer (TSCT) excited states have been disclosed to be capable of exhibiting thermally activated delayed fluorescence (TADF), but to realize high-efficiency long-wavelength emission still remains a challenge. Herein, we report a series of strongly emissive orange-red and red TSCT-TADF emitters having (quasi)planar and rigid donor and acceptor segments which are placed in close proximity and orientated in a cofacial manner. Emission maxima (λem) of 594−599 nm with photoluminescence quantum yields (PLQYs) of up to 91% and delayed fluorescence lifetimes of down to 4.9 μs have been achieved for new acceptor-donor-acceptor (A-D-A) molecules in doped thin films. The presence of multiple acceptors and the strong intramolecular π-stacking interactions have been unveiled to be crucial for the efficient low-energy TSCT-TADF emissions. Organic light-emitting diodes (OLEDs) based on the new A-D-A emitters demonstrated electroluminescence with maximum external quantum efficiencies (EQEs) of up to 23.2% for the red TSCT-TADF emitters. An EQE of 18.9% at the brightness of 1000 cd m−2 represents one of the highest values for red TADF OLEDs. This work demonstrates a modular approach for developing high-performance red TADF emitters through engineering through-space interactions, and it may also provide implications to the design of TADF emitter with other colours.
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Affiliation(s)
- Chenglin Jiang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jingsheng Miao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Danwen Zhang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Zhenhua Wen
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Chuluo Yang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
| | - Kai Li
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518055, China
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27
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Yang SY, Qu YK, Liao LS, Jiang ZQ, Lee ST. Research Progress of Intramolecular π-Stacked Small Molecules for Device Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104125. [PMID: 34595783 DOI: 10.1002/adma.202104125] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/18/2021] [Indexed: 06/13/2023]
Abstract
Organic semiconductors can be designed and constructed in π-stacked structures instead of the conventional π-conjugated structures. Through-space interaction (TSI) occurs in π-stacked optoelectronic materials. Thus, unlike electronic coupling along the conjugated chain, the functional groups can stack closely to facilitate spatial electron communication. Using π-stacked motifs, chemists and materials scientists can find new ways for constructing materials with aggregation-induced emission (AIE), thermally activated delayed fluorescence (TADF), circularly polarized luminescence (CPL), and room-temperature phosphorescence (RTP), as well as enhanced molecular conductance. Organic optoelectronic devices based on π-stacked molecules have exhibited very promising performance, with some of them exceeding π-conjugated analogues. Recently, reports on various organic π-stacked structures have grown rapidly, prompting this review. Representative molecular scaffolds and newly developed π-stacked systems could stimulate more attention on through-space charge transfer the well-known through-bond charge transfer. Finally, the opportunities and challenges for utilizing and improving particular materials are discussed. The previous achievements and upcoming prospects may provide new insights into the theory, materials, and devices in the field of organic semiconductors.
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Affiliation(s)
- Sheng-Yi Yang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, P. R. China
| | - Yang-Kun Qu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, P. R. China
| | - Liang-Sheng Liao
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, P. R. China
- Macao Institute of Materials Science and Engineering, Macau University of Science and Technology, Taipa, Macau SAR, 999078, P. R. China
| | - Zuo-Quan Jiang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, P. R. China
| | - Shuit-Tong Lee
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu, 215123, P. R. China
- Macao Institute of Materials Science and Engineering, Macau University of Science and Technology, Taipa, Macau SAR, 999078, P. R. China
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28
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Sanfui S, Usman M, Sarkar S, Pramanik S, Garribba E, Rath SP. Highly Oxidized Cobalt Porphyrin Dimer: Control of Spin Coupling via a Bridge. Inorg Chem 2022; 61:8419-8430. [PMID: 35613476 DOI: 10.1021/acs.inorgchem.1c03807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A cobalt porphyrin dimer is constructed in which two Co(II)porphyrins are connected covalently through a redox-active diethylpyrrole moiety via a flexible but "nonconjugated" methylene bridge. Upon oxidation with even a mild oxidant such as iodine, each cobalt(II) center and porphyrin ring undergo 1e- oxidation, leading to the formation of a 4e--oxidized cobalt(III)porphyrin dication diradical complex. Other oxidants such as Cl2 and Br2 also produce similar results. To stabilize such highly oxidized dication diradicals, the "nonconjugated" methylene spacer undergoes a facile and spontaneous oxidation to form a methine group with a drastic structural change, thereby making the bridge fully π-conjugated and enabling through-bond communication. This results in a strong spin coupling between two π-cation radicals which stabilizes the singlet state. The experimental observations are also strongly supported by extensive density functional theory calculations. The present study highlights the crucial role played by the nature of the bridge in the long-range electronic communication.
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Affiliation(s)
- Sarnali Sanfui
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Sabyasachi Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Subhadip Pramanik
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Eugenio Garribba
- Dipartimento di Scienze Mediche, Chirurgiche e Sperimentali, Università di Sassari, Viale San Pietro, Sassari I-07100, Italy
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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Sun R, Liu M, Zheng SL, Dogutan DK, Costentin C, Nocera DG. Proton-coupled electron transfer of macrocyclic ring hydrogenation: The chlorinphlorin. Proc Natl Acad Sci U S A 2022; 119:e2122063119. [PMID: 35533271 PMCID: PMC9171799 DOI: 10.1073/pnas.2122063119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/07/2022] [Indexed: 11/18/2022] Open
Abstract
SignificanceThe chemical reduction of unsaturated bonds occurs by hydrogenation with H2 as the reductant. Conversely, in biology, the unavailability of H2 engenders the typical reduction of unsaturated bonds with electrons and protons from different cofactors, requiring olefin hydrogenation to occur by proton-coupled electron transfer (PCET). Moreover, the redox noninnocence of tetrapyrrole macrocycles furnishes unusual PCET intermediates, including the phlorin, which is an intermediate in tetrapyrrole ring reductions. Whereas the phlorin of a porphyrin is well established, the phlorin of a chlorin is enigmatic. By controlling the PCET reactivity of a chlorin, including the use of a hangman functionality to manage the proton transfer, the formation of a chlorinphlorin by PCET is realized, and the mechanism for its formation is defined.
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Affiliation(s)
- Rui Sun
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Mengran Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Dilek K. Dogutan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Cyrille Costentin
- Université Grenoble Alpes, CNRS, Grenoble, 38000 France
- Université Paris Cité, Paris, 75013 France
| | - Daniel G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
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30
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Bhunia S, Ghatak A, Dey A. Second Sphere Effects on Oxygen Reduction and Peroxide Activation by Mononuclear Iron Porphyrins and Related Systems. Chem Rev 2022; 122:12370-12426. [PMID: 35404575 DOI: 10.1021/acs.chemrev.1c01021] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Activation and reduction of O2 and H2O2 by synthetic and biosynthetic iron porphyrin models have proved to be a versatile platform for evaluating second-sphere effects deemed important in naturally occurring heme active sites. Advances in synthetic techniques have made it possible to install different functional groups around the porphyrin ligand, recreating artificial analogues of the proximal and distal sites encountered in the heme proteins. Using judicious choices of these substituents, several of the elegant second-sphere effects that are proposed to be important in the reactivity of key heme proteins have been evaluated under controlled environments, adding fundamental insight into the roles played by these weak interactions in nature. This review presents a detailed description of these efforts and how these have not only demystified these second-sphere effects but also how the knowledge obtained resulted in functional mimics of these heme enzymes.
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Affiliation(s)
- Sarmistha Bhunia
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, India
| | - Arnab Ghatak
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, India
| | - Abhishek Dey
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, India
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31
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Cai Q, Tran LK, Qiu T, Eddy JW, Pham TN, Yap GPA, Rosenthal J. An Easily Prepared Monomeric Cobalt(II) Tetrapyrrole Complex That Efficiently Promotes the 4e -/4H + Peractivation of O 2 to Water. Inorg Chem 2022; 61:5442-5451. [PMID: 35358381 DOI: 10.1021/acs.inorgchem.1c03766] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The selective 4e-/4H+ reduction of dioxygen to water is an important reaction that takes place at the cathode of fuel cells. Monomeric aromatic tetrapyrroles (such as porphyrins, phthalocyanines, and corroles) coordinated to Co(II) or Co(III) have been considered as oxygen reduction catalysts due to their low cost and relative ease of synthesis. However, these systems have been repeatedly shown to be selective for O2 reduction by the less desired 2e-/2H+ pathway to yield hydrogen peroxide. Herein, we report the initial synthesis and study of a Co(II) tetrapyrrole complex based on a nonaromatic isocorrole scaffold that is competent for 4e-/4H+ oxygen reduction reaction (ORR). This Co(II) 10,10-dimethyl isocorrole (Co[10-DMIC]) is obtained in just four simple steps and has excellent yield from a known dipyrromethane synthon. Evaluation of the steady state spectroscopic and redox properties of Co[10-DMIC] against those of Co porphyrin (cobalt 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, [Co(TPFPP)]) and corrole (cobalt 5,10,15-tris(pentafluorophenyl)corrole triphenylphosphine, Co[TPFPC](PPh3)) homologues demonstrated that the spectroscopic and electrochemical properties of the isocorrole are distinct from those displayed by more traditional aromatic tetrapyrroles. Further, the investigation of the ORR activity of Co[10-DMIC] using a combination of electrochemical and chemical reduction studies revealed that this simple, unadorned monomeric Co(II) tetrapyrrole is ∼85% selective for the 4e-/4H+ reduction of O2 to H2O over the more kinetically facile 2e-/2H+ process that delivers H2O2. In contrast, the same ORR evaluations conducted for the Co porphyrin and corrole homologues demonstrated that these traditional aromatic systems catalyze the 2e-/2H+ conversion of O2 to H2O2 with near complete selectivity. Despite being a simple, easily prepared, monomeric tetrapyrrole platform, Co[10-DMIC] supports an ORR catalysis that has historically only been achieved using elaborate porphyrinoid-based architectures that incorporate pendant proton-transfer groups or ditopic molecular clefts or that impose cofacially oriented O2 binding sites. Accordingly, Co[10-DMIC] represents the first simple, unadorned, monomeric metalloisocorrole complex that can be easily prepared and shows a privileged performance for the 4e-/4H+ peractivation of O2 to water as compared to other simple cobalt containing tetrapyrroles.
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Affiliation(s)
- Qiuqi Cai
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Linh K Tran
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Tian Qiu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Jennifer W Eddy
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Trong-Nhan Pham
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Joel Rosenthal
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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Warburton RE, Soudackov AV, Hammes-Schiffer S. Theoretical Modeling of Electrochemical Proton-Coupled Electron Transfer. Chem Rev 2022; 122:10599-10650. [PMID: 35230812 DOI: 10.1021/acs.chemrev.1c00929] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Proton-coupled electron transfer (PCET) plays an essential role in a wide range of electrocatalytic processes. A vast array of theoretical and computational methods have been developed to study electrochemical PCET. These methods can be used to calculate redox potentials and pKa values for molecular electrocatalysts, proton-coupled redox potentials and bond dissociation free energies for PCET at metal and semiconductor interfaces, and reorganization energies associated with electrochemical PCET. Periodic density functional theory can also be used to compute PCET activation energies and perform molecular dynamics simulations of electrochemical interfaces. Various approaches for maintaining a constant electrode potential in electronic structure calculations and modeling complex interactions in the electric double layer (EDL) have been developed. Theoretical formulations for both homogeneous and heterogeneous electrochemical PCET spanning the adiabatic, nonadiabatic, and solvent-controlled regimes have been developed and provide analytical expressions for the rate constants and current densities as functions of applied potential. The quantum mechanical treatment of the proton and inclusion of excited vibronic states have been shown to be critical for describing experimental data, such as Tafel slopes and potential-dependent kinetic isotope effects. The calculated rate constants can be used as input to microkinetic models and voltammogram simulations to elucidate complex electrocatalytic processes.
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Affiliation(s)
- Robert E Warburton
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Alexander V Soudackov
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Sharon Hammes-Schiffer
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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33
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Ghosh I, Chakraborty B, Bera A, Paul S, Paine TK. Selective oxygenation of C-H and CC bonds with H 2O 2 by high-spin cobalt(II)-carboxylate complexes. Dalton Trans 2022; 51:2480-2492. [PMID: 35050271 DOI: 10.1039/d1dt02235k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Four cobalt(II)-carboxylate complexes [(6-Me3-TPA)CoII(benzoate)](BPh4) (1), [(6-Me3-TPA)CoII(benzilate)](ClO4) (2), [(6-Me3-TPA)CoII(mandelate)](BPh4) (3), and [(6-Me3-TPA)CoII(MPA)](BPh4) (4) (HMPA = 2-methoxy-2-phenylacetic acid) of the 6-Me3-TPA (tris((6-methylpyridin-2-yl)methyl)amine) ligand were isolated to investigate their ability in H2O2-dependent selective oxygenation of C-H and CC bonds. All six-coordinate complexes contain a high-spin cobalt(II) center. While the cobalt(II) complexes are inert toward dioxygen, each of these complexes reacts readily with hydrogen peroxide to form a diamagnetic cobalt(III) species, which decays with time leading to the oxidation of the methyl groups on the pyridine rings of the supporting ligand. Intramolecular ligand oxidation by the cobalt-based oxidant is partially inhibited in the presence of external substrates, and the substrates are converted to their corresponding oxidized products. Kinetic studies and labelling experiments indicate the involvement of a metal-based oxidant in affecting the chemo- and stereo-selective catalytic oxygenation of aliphatic C-H bonds and epoxidation of alkenes. An electrophilic cobalt-oxygen species that exhibits a kinetic isotope effect (KIE) value of 5.3 in toluene oxidation by 1 is proposed as the active oxidant. Among the complexes, the cobalt(II)-benzoate (1) and cobalt(II)-MPA (4) complexes display better catalytic activity compared to their α-hydroxy analogues (2 and 3). Catalytic studies with the cobalt(II)-acetonitrile complex [(6-Me3-TPA)CoII(CH3CN)2](ClO4)2 (5) in the presence and absence of externally added benzoate support the role of the carboxylate co-ligand in oxidation reactions. The proposed catalytic reaction involves a carboxylate-bridged dicobalt complex in the activation of H2O2 followed by the oxidation of substrates by a metal-based oxidant.
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Affiliation(s)
- Ivy Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India.
| | - Biswarup Chakraborty
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India.
| | - Abhijit Bera
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India.
| | - Satadal Paul
- Department of Chemistry, Bangabasi Morning College, 19, Rajkumar Chakraborty Sarani, Kolkata - 700 009, India
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India.
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34
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Nocera DG. Proton-Coupled Electron Transfer: The Engine of Energy Conversion and Storage. J Am Chem Soc 2022; 144:1069-1081. [PMID: 35023740 DOI: 10.1021/jacs.1c10444] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proton-coupled electron transfer (PCET) underpins energy conversion in chemistry and biology. Four energy systems are described whose discoveries are based on PCET: the water splitting chemistry of the Artificial Leaf, the carbon fixation chemistry of the Bionic Leaf-C, the nitrogen fixation chemistry of the Bionic Leaf-N and the Coordination Chemistry Flow Battery (CCFB). Whereas the Artificial Leaf, Bionic Leaf-C, and Bionic Leaf-N require strong coupling between electron and proton to reduce energetic barriers to enable high energy efficiencies, the CCFB requires complete decoupling of the electron and proton so as to avoid parasitic energy-wasting reactions. The proper design of PCET in these systems facilitates their implementation in the areas of (i) centralized large scale grid storage of electricity and (ii) decentralized energy storage/conversion using only sunlight, air and any water source to produce fuel and food within a sustainable cycle for the biogenic elements of C, N and P.
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Affiliation(s)
- Daniel G Nocera
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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35
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Yu XC, Zhang CC, Wang LT, Li JZ, Li T, Wei WT. The synthesis of seven- and eight-membered rings by radical strategies. Org Chem Front 2022. [DOI: 10.1039/d2qo00774f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radical strategies for preparation of seven- or eight-membered rings.
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Affiliation(s)
- Xuan-Chi Yu
- Institute of Drug Discovery Technology, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211, China
| | - Can-Can Zhang
- Institute of Drug Discovery Technology, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211, China
| | - Ling-Tao Wang
- Institute of Drug Discovery Technology, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211, China
| | - Jiao-Zhe Li
- Institute of Drug Discovery Technology, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211, China
| | - Ting Li
- College of Chemistry and Pharmaceutical Engineering, Nanyang Normal University, Nanyang, Henan, 473061, China
| | - Wen-Ting Wei
- Institute of Drug Discovery Technology, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211, China
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36
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Hanana M, Kahlfuss C, Weiss J, Cornut R, Jousselme B, Wytko JA, Campidelli S. ORR activity of metalated phenanthroline-strapped porphyrin adsorbed on carbon nanotubes. CR CHIM 2021. [DOI: 10.5802/crchim.86] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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37
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Xiao F, Wang YC, Wu ZP, Chen G, Yang F, Zhu S, Siddharth K, Kong Z, Lu A, Li JC, Zhong CJ, Zhou ZY, Shao M. Recent Advances in Electrocatalysts for Proton Exchange Membrane Fuel Cells and Alkaline Membrane Fuel Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006292. [PMID: 33749011 DOI: 10.1002/adma.202006292] [Citation(s) in RCA: 139] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/10/2020] [Indexed: 05/18/2023]
Abstract
The rapid progress of proton exchange membrane fuel cells (PEMFCs) and alkaline exchange membrane fuel cells (AMFCs) has boosted the hydrogen economy concept via diverse energy applications in the past decades. For a holistic understanding of the development status of PEMFCs and AMFCs, recent advancements in electrocatalyst design and catalyst layer optimization, along with cell performance in terms of activity and durability in PEMFCs and AMFCs, are summarized here. The activity, stability, and fuel cell performance of different types of electrocatalysts for both oxygen reduction reaction and hydrogen oxidation reaction are discussed and compared. Research directions on the further development of active, stable, and low-cost electrocatalysts to meet the ultimate commercialization of PEMFCs and AMFCs are also discussed.
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Affiliation(s)
- Fei Xiao
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yu-Cheng Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Zhi-Peng Wu
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Guangyu Chen
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Guangzhou, 511458, China
| | - Fei Yang
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Shangqian Zhu
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Kumar Siddharth
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Zhijie Kong
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Aolin Lu
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Jin-Cheng Li
- Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Guangzhou, 511458, China
| | - Chuan-Jian Zhong
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Zhi-You Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Minhua Shao
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Guangzhou, 511458, China
- Energy Institute, and Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing 1st RD, South Area, Hi-tech Park, Nanshan, Shenzhen, 518057, China
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38
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PCET to bound-superoxide by NADH and NADHX in aqueous-acid media: a kinetic inspection. J CHEM SCI 2021. [DOI: 10.1007/s12039-021-01994-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Singh AK, Usman M, Sarkar S, Sciortino G, Kumar D, Garribba E, Rath SP. Ferromagnetic Coupling in Oxidovanadium(IV)-Porphyrin Radical Dimers. Inorg Chem 2021; 60:16492-16506. [PMID: 34664950 DOI: 10.1021/acs.inorgchem.1c02331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three different oxidovanadium(IV) porphyrin dimers with anti, cis, and trans arrangements of the two rings have been synthesized by changing the bridge between the porphyrin macrocycles. This provides a unique opportunity to investigate the role of the bridge and spatial arrangement between the two VIVO centers for their electronic communication and magnetic coupling. They were characterized by the combined application of XRD analysis, UV-vis and electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry, magnetic susceptibility, and DFT calculations. One- and two-electron oxidations produce mono- and dication diradical species, respectively, which display an unusual ferromagnetic interaction between the unpaired spins of vanadium(IV) and porphyrin π-cation radical, in contrast to other metalloporphyrin dimers. The oxidized species show a dissimilar behavior between cis and trans isomers. The ferromagnetic coupling occurs between the porphyrin π-cation radical and the unpaired electron of the VIVO ion on the dxy orbital, orthogonal to the porphyrin-based molecular orbitals a1u and a2u.
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Affiliation(s)
- Akhil Kumar Singh
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Sabyasachi Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Giuseppe Sciortino
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via Vienna 2, I-07100 Sassari, Italy.,Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), 43007 Tarragona, Spain
| | - Devesh Kumar
- Department of Physics, School for Physical and Decision Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India
| | - Eugenio Garribba
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via Vienna 2, I-07100 Sassari, Italy
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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40
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Huang G, Li Y, Du S, Wu Y, Chen R, Zhang J, Cheng Y, Lu S, Tao L, Wang S. Silica-facilitated proton transfer for high-temperature proton-exchange membrane fuel cells. Sci China Chem 2021. [DOI: 10.1007/s11426-021-1142-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Li Y, Wang N, Lei H, Li X, Zheng H, Wang H, Zhang W, Cao R. Bioinspired N4-metallomacrocycles for electrocatalytic oxygen reduction reaction. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213996] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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42
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Nichols AW, Cook EN, Gan YJ, Miedaner PR, Dressel JM, Dickie DA, Shafaat HS, Machan CW. Pendent Relay Enhances H 2O 2 Selectivity during Dioxygen Reduction Mediated by Bipyridine-Based Co-N 2O 2 Complexes. J Am Chem Soc 2021; 143:13065-13073. [PMID: 34380313 DOI: 10.1021/jacs.1c03381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Generally, cobalt-N2O2 complexes show selectivity for hydrogen peroxide during electrochemical dioxygen (O2) reduction. We recently reported a Co(III)-N2O2 complex with a 2,2'-bipyridine-based ligand backbone which showed alternative selectivity: H2O was observed as the primary reduction product from O2 (71 ± 5%) with decamethylferrocene as a chemical reductant and acetic acid as a proton donor in methanol solution. We hypothesized that the key selectivity difference in this case arises in part from increased favorability of protonation at the distal O position of the key intermediate Co(III)-hydroperoxide species. To interrogate this hypothesis, we have prepared a new Co(III) compound that contains pendent -OMe groups poised to direct protonation toward the proximal O atom of this hydroperoxo intermediate. Mechanistic studies in acetonitrile (MeCN) solution reveal two regimes are possible in the catalytic response, dependent on added acid strength and the presence of the pendent proton donor relay. In the presence of stronger acids, the activity of the complex containing pendent relays becomes O2 dependent, implying a shift to Co(III)-superoxide protonation as the rate-determining step. Interestingly, the inclusion of the relay results in primarily H2O2 production in MeCN, despite minimal difference between the standard reduction potentials of the three complexes tested. EPR spectroscopic studies indicate the formation of Co(III)-superoxide species in the presence of exogenous base, with greater O2 reactivity observed in the presence of the pendent -OMe groups.
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Affiliation(s)
- Asa W Nichols
- Department of Chemistry, University of Virginia, McCormick Rd., PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Emma N Cook
- Department of Chemistry, University of Virginia, McCormick Rd., PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Yunqiao J Gan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Ave., Columbus, Ohio 43210, United States
| | - Peter R Miedaner
- Department of Chemistry, University of Virginia, McCormick Rd., PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Julia M Dressel
- Department of Chemistry, University of Virginia, McCormick Rd., PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, McCormick Rd., PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Hannah S Shafaat
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Ave., Columbus, Ohio 43210, United States
| | - Charles W Machan
- Department of Chemistry, University of Virginia, McCormick Rd., PO Box 400319, Charlottesville, Virginia 22904-4319, United States
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Kumar A, Usman M, Samanta D, Rath SP. Through Bridge Spin Coupling in Homo- and Heterobimetallic Porphyrin Dimers upon Stepwise Oxidations: A Spectroscopic and Theoretical Investigation. Chemistry 2021; 27:11428-11441. [PMID: 34061401 DOI: 10.1002/chem.202101384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Indexed: 12/16/2022]
Abstract
We have described copper(II)-iron(III) and copper(II)-manganese(III) heterobimetallic porphyrin dimers and compared them with the corresponding homobimetallic analogs. UV-visible spectra are very distinct in the heterometallic species while electrochemical studies demonstrate that these species, as compared to the homobimetallic analog, are much easier to oxidize. Combined Mössbauer, EPR, NMR, magnetic and UV-visible spectroscopic studies show that upon 2e-oxidation of the heterobimetallic complexes only ring-centered oxidation occurs. The energy differences between HOMO and LUMO are linearly dependent with the low-energy NIR band obtained for the 2e-oxidized complexes. Also, strong electronic communication between two porphyrin rings through the bridge facilitates coupling between various unpaired spins present while the coupling model depends on the nature of metal ions used. While unpaired spins of Fe(III) and the porphyrin π-cation radical are strongly antiferromagnetically coupled, such coupling is rather weak between Mn(III) and a porphyrin π-cation radical. Moreover, the coupling between two π-cation radicals are much stronger in the 2e-oxidized complexes of dimanganese(III) and copper(II)-manganese(III) porphyrin dimers as compared to their diiron(III) and copper(II)-iron(III) analogs. Furthermore, coupling between the unpaired spins of a π-cation radical and copper(II) is much stronger in the 2e-oxidized complex of copper(II)-iron(III) porphyrin dimer as compared to its copper(II)-manganese(III) analog. The Mulliken spin density distributions in 2e-oxidized homo- and heterobimetallic complexes show symmetric and asymmetric spread between the two macrocycles, respectively. In both the 2e-oxidized heterobimetallic complexes, the Cu(II) porphyrin center acts as a charge donor while Fe(III)/Mn(III) porphyrin center act as a charge acceptor. The experimental observations are also strongly supported by DFT calculations.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Deepannita Samanta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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Lang C, Li J, Yang KR, Wang Y, He D, Thorne JE, Croslow S, Dong Q, Zhao Y, Prostko G, Brudvig GW, Batista VS, Waegele MM, Wang D. Observation of a potential-dependent switch of water-oxidation mechanism on Co-oxide-based catalysts. Chem 2021. [DOI: 10.1016/j.chempr.2021.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sigmund LM, Ehlert C, Enders M, Graf J, Gryn'ova G, Greb L. Disauerstoffaktivierung und Pyrrol‐α‐Spaltung mit Calix[4]pyrrolatoaluminaten: Enzymmodell durch strukturellen Zwang. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104916] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lukas Maximilian Sigmund
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Christopher Ehlert
- Heidelberger Institut für Theoretische Studien (HITS gGmbH) Schloss-Wolfsbrunnenweg 35 69118 Heidelberg Deutschland
- Interdisziplinäres Zentrum für wissenschaftliches Rechnen (IWR) Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 205 69120 Heidelberg Deutschland
| | - Markus Enders
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Jürgen Graf
- Organisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Ganna Gryn'ova
- Heidelberger Institut für Theoretische Studien (HITS gGmbH) Schloss-Wolfsbrunnenweg 35 69118 Heidelberg Deutschland
- Interdisziplinäres Zentrum für wissenschaftliches Rechnen (IWR) Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 205 69120 Heidelberg Deutschland
| | - Lutz Greb
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
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Pistner AJ, Martin MI, Yap GP, Rosenthal J. Synthesis, structure, electronic characterization, and halogenation of gold(III) phlorin complexes. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500565] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The metalation chemistry of the phlorin, which is a non-aromatic tetrapyrrole macrocycle containing a single sp3-hybridized meso-carbon has remained underdeveloped, as compared to that of more traditional tetrapyrroles such as porphyrins, corroles and phthalocyanines. There have been few prior efforts to prepare metallophlorins, and those that have been reported have relied on either reduction or nucleophilic attack of parent metalloporphyrins, rather than direct metalation of freebase phlorin constructs. In this work, an alternate synthetic approach for preparation of gold(III) phlorin complexes that involves the first direct metalation of two different freebase phlorin derivatives (3H(Phl[Formula: see text] and 3H(Phl[Formula: see text] with AuBr3 to produce the stable and fully isolable gold(III) phlorin complexes Au(Phl[Formula: see text] and Au(Phl[Formula: see text] is reported. The first structural characterization of a metallophlorin bearing geminal dimethyl substituents at the sp3-hybridized meso-carbon via X-ray crystallography is also reported. In addition to the preparation of Au(Phl[Formula: see text] and Au(Phl[Formula: see text], the UV-vis absorption and redox properties of these two gold(III) phlorins in comparison to those of their freebase homologues is also detailed. Notably, the metallophlorins are characterized by panchromatic absorbance profiles and intense and broad bands that span the long-visible and into the near-IR regions, as well as two fully reversible oxidation and reduction waves as probed by cyclic voltammetry. Finally, the chlorination of Au(Phl[Formula: see text] using PhI(Cl[Formula: see text] was probed and it was found that this regioslective reaction generates monochlorinated (Au(Phl[Formula: see text]Cl)) and dichlorinated (Au(Phl[Formula: see text]Cl[Formula: see text] products, which were both structurally characterized by X-ray crystallography.
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Affiliation(s)
- Allen J. Pistner
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Maxwell I. Martin
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Glenn P.A. Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Joel Rosenthal
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
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Roubelakis MM, Bediako DK, Dogutan DK, Nocera DG. Influence of the proton relay spacer on hydrogen electrocatalysis by cobalt hangman porphyrins. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s108842462150067x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A cobalt hangman porphyrin system with a phenyl spacer between the porphyrin ring and an internal carboxylic acid group as well as its non-hangman analogue were synthesized and utilized for the study of the proton-coupled electron transfer (PCET) kinetics attendant to electrocatalytic hydrogen evolution. Cyclic voltammetry (CV) together with simulations show that a short distance between the proton relay and the redox active cobalt center as well as the increased proton donating strength results in superior catalytic activity. The mechanism of hydrogen generation is at the nexus of proton transfer–electron transfer (PTET) and concerted proton–electron transfer (CPET), as opposed to an ETPT mechanism that is characteristic of hangman systems with longer proton relay networks.
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Affiliation(s)
- Manolis M. Roubelakis
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - D. Kwabena Bediako
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Dilek K. Dogutan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Daniel G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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Sigmund LM, Ehlert C, Enders M, Graf J, Gryn'ova G, Greb L. Dioxygen Activation and Pyrrole α-Cleavage with Calix[4]pyrrolato Aluminates: Enzyme Model by Structural Constraint. Angew Chem Int Ed Engl 2021; 60:15632-15640. [PMID: 33955154 PMCID: PMC8362023 DOI: 10.1002/anie.202104916] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Indexed: 01/30/2023]
Abstract
The present work describes the reaction of triplet dioxygen with the porphyrinogenic calix[4]pyrrolato aluminates to alkylperoxido aluminates in high selectivity. Multiconfigurational quantum chemical computations disclose the mechanism for this spin‐forbidden process. Despite a negligible spin–orbit coupling constant, the intersystem crossing (ISC) is facilitated by singlet and triplet state degeneracy and spin–vibronic coupling. The formed peroxides are stable toward external substrates but undergo an unprecedented oxidative pyrrole α‐cleavage by ligand aromatization/dearomatization‐initiated O−O σ‐bond scission. A detailed comparison of the calix[4]pyrrolato aluminates with dioxygen‐related enzymology provides insights into the ISC of metal‐ or cofactor‐free enzymes. It substantiates the importance of structural constraint and element–ligand cooperativity for the functions of aerobic life.
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Affiliation(s)
- Lukas Maximilian Sigmund
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Christopher Ehlert
- Heidelberg Institute for Theoretical Studies (HITS gGmbH), Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing (IWR), Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 205, 69120, Heidelberg, Germany
| | - Markus Enders
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Jürgen Graf
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Ganna Gryn'ova
- Heidelberg Institute for Theoretical Studies (HITS gGmbH), Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing (IWR), Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 205, 69120, Heidelberg, Germany
| | - Lutz Greb
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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49
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Wang W, Tse ECM. Proton Removal Kinetics That Govern the Hydrogen Peroxide Oxidation Activity of Heterogeneous Bioinorganic Platforms. Inorg Chem 2021; 60:6900-6910. [PMID: 33621073 DOI: 10.1021/acs.inorgchem.0c03743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Precise regulation of proton-coupled electron-transfer (PCET) rates holds the key to simultaneously optimizing the turnover frequency and product selectivity of redox reactions that are central to the realization of renewable energy schemes in a sustainable future. In this work, a self-assembled monolayer (SAM) of a Ru complex electrografted onto a glassy carbon (GC) electrode was prepared as a heterogeneous electrocatalytic interface to facilitate the hydrogen peroxide (H2O2) oxidation half-cell reaction of a direct hydrogen peroxide/hydrogen peroxide fuel cell. A functional lipid membrane embedded with catalytic amounts of proton carriers was appended on top of the Ru SAM to construct a hybrid bilayer membrane (HBM) platform that can modulate the thermodynamics and kinetics of proton- and electron-transfer steps independently. The performances of the as-prepared Ru SAMs and HBMs toward H2O2 oxidation were investigated using electrochemical means, kinetic isotope effect (KIE) studies, and Tafel analyses. Proton carriers featuring borate, phosphate, and nitrile headgroups were found to dictate the transmembrane proton removal rate, thereby controlling the H2O2 oxidation activity. The first significance of this work was the expansion of HBM platforms to GC substrates to overcome the limited redox potential window on gold thiol systems, thereby enabling electrochemical investigations of anodic reactions at the SAM-lipid interface. The second highlight of this work was demonstrating for the first time that deprotonation kinetics can be taken advantage of to enhance the electrocatalytic oxidation performance of a metal complex anchored at the SAM-lipid interface of a HBM platform. When the knowledge gaps regarding how PCET steps govern redox pathways are closed, the advances achieved using our unique bioinorganic platform are envisioned to accelerate the understanding and optimization of electrocatalytic processes involving proton- and electron- transfer steps that are fundamental to the development of high-performance energy devices.
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Affiliation(s)
- Wanying Wang
- Department of Chemistry, HKU-CAS Joint Laboratory on New Materials, University of Hong Kong (HKU), Pok Fu Lam, Hong Kong Special Administrative Region, China
| | - Edmund C M Tse
- Department of Chemistry, HKU-CAS Joint Laboratory on New Materials, University of Hong Kong (HKU), Pok Fu Lam, Hong Kong Special Administrative Region, China.,HKU Zhejiang Institute of Research and Innovation, Zhejiang 311305, China
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Iacobini C, Vitale M, Pesce C, Pugliese G, Menini S. Diabetic Complications and Oxidative Stress: A 20-Year Voyage Back in Time and Back to the Future. Antioxidants (Basel) 2021; 10:727. [PMID: 34063078 PMCID: PMC8147954 DOI: 10.3390/antiox10050727] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 02/07/2023] Open
Abstract
Twenty years have passed since Brownlee and colleagues proposed a single unifying mechanism for diabetic complications, introducing a turning point in this field of research. For the first time, reactive oxygen species (ROS) were identified as the causal link between hyperglycemia and four seemingly independent pathways that are involved in the pathogenesis of diabetes-associated vascular disease. Before and after this milestone in diabetes research, hundreds of articles describe a role for ROS, but the failure of clinical trials to demonstrate antioxidant benefits and some recent experimental studies showing that ROS are dispensable for the pathogenesis of diabetic complications call for time to reflect. This twenty-year journey focuses on the most relevant literature regarding the main sources of ROS generation in diabetes and their role in the pathogenesis of cell dysfunction and diabetic complications. To identify future research directions, this review discusses the evidence in favor and against oxidative stress as an initial event in the cellular biochemical abnormalities induced by hyperglycemia. It also explores possible alternative mechanisms, including carbonyl stress and the Warburg effect, linking glucose and lipid excess, mitochondrial dysfunction, and the activation of alternative pathways of glucose metabolism leading to vascular cell injury and inflammation.
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Affiliation(s)
- Carla Iacobini
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy; (C.I.); (M.V.); (S.M.)
| | - Martina Vitale
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy; (C.I.); (M.V.); (S.M.)
| | - Carlo Pesce
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and Maternal Infantile Sciences (DINOGMI), Department of Excellence of MIUR, University of Genoa Medical School, 16132 Genoa, Italy;
| | - Giuseppe Pugliese
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy; (C.I.); (M.V.); (S.M.)
| | - Stefano Menini
- Department of Clinical and Molecular Medicine, “La Sapienza” University, 00189 Rome, Italy; (C.I.); (M.V.); (S.M.)
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