1
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Le Dé Q, Valyaev DA, Simonneau A. Nitrogen Fixation by Manganese Complexes - Waiting for the Rush? Chemistry 2024; 30:e202400784. [PMID: 38709147 DOI: 10.1002/chem.202400784] [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: 02/26/2024] [Revised: 05/05/2024] [Accepted: 05/06/2024] [Indexed: 05/07/2024]
Abstract
Manganese is currently experiencing a great deal of attention in homogeneous catalysis as a sustainable alternative to platinum group metals due to its abundance, affordable price and low toxicity. While homogeneous nitrogen fixation employing well-defined transition metal complexes has been an important part of coordination chemistry, manganese derivatives have been only sporadically used in this research area. In this contribution, the authors systematically cover manganese organometallic chemistry related to N2 activation spanning almost 60 years, identify apparent pitfalls and outline encouraging perspectives for its future development.
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Affiliation(s)
- Quentin Le Dé
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - Dmitry A Valyaev
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - Antoine Simonneau
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
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2
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Mahato S, VandeVen W, MacNeil GA, Pulfer JM, Storr T. Untangling ancillary ligand donation versus locus of oxidation effects on metal nitride reactivity. Chem Sci 2024; 15:2211-2220. [PMID: 38332824 PMCID: PMC10848731 DOI: 10.1039/d3sc05403a] [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: 10/12/2023] [Accepted: 01/01/2024] [Indexed: 02/10/2024] Open
Abstract
We detail the relative role of ancillary ligand electron-donating ability in comparison to the locus of oxidation (either metal or ligand) on the electrophilic reactivity of a series of oxidized Mn salen nitride complexes. The electron-donating ability of the ancillary salen ligand was tuned via the para-phenolate substituent (R = CF3, H, tBu, OiPr, NMe2, NEt2) in order to have minimal effect on the geometry at the metal center. Through a suite of experimental (electrochemistry, electron paramagnetic resonance spectroscopy, UV-vis-NIR spectroscopy) and theoretical (density functional theory) techniques, we have demonstrated that metal-based oxidation to [MnVI(SalR)N]+ occurs for R = CF3, H, tBu, OiPr, while ligand radical formation to [MnV(SalR)N]+˙ occurs with the more electron-donating substituents R = NMe2, NEt2. We next investigated the reactivity of the electrophilic nitride with triarylphosphines to form a MnIV phosphoraneiminato adduct and determined that the rate of reaction decreases as the electron-donating ability of the salen para-phenolate substituent is increased. Using a Hammett plot, we find a break in the Hammett relation between R = OiPr and R = NMe2, without a change in mechanism, consistent with the locus of oxidation exhibiting a dominant effect on nitride reactivity, and not the overall donating ability of the ancillary salen ligand. This work differentiates between the subtle and interconnected effects of ancillary ligand electron-donating ability, and locus of oxidation, on electrophilic nitride reactivity.
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Affiliation(s)
- Samyadeb Mahato
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Warren VandeVen
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Gregory A MacNeil
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Jason M Pulfer
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Tim Storr
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
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3
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Kim J, Park Y, Chirik PJ. Iridium-Catalyzed Hydrogenation of a Phenoxy Radical to the Phenol: Overcoming Catalyst Deactivation with Visible Light Irradiation. Inorg Chem 2023; 62:19582-19592. [PMID: 37980598 DOI: 10.1021/acs.inorgchem.3c02918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Piano-stool iridium hydride complexes bearing phenylpyridine ligands are effective precatalysts for promoting the formation of element-hydrogen bonds using H2 as the stoichiometric H-atom source. Irradiation with blue light resulted in a profound enhancement of catalyst turnover for the iridium-catalyzed hydrogenation of the aryloxyl radical 2,4,6-tBu3-C6H2O• to the corresponding phenol. Monitoring the progress of the reaction revealed the formation of an iridium 3,3-dimethyl-2,3-dihydrobenzofuranyl compound arising from two C-H activation events following the proton-coupled electron transfer (PCET) step. Under thermal conditions, this compound was inactive for catalytic aryloxide hydrogenation, representing a deactivation pathway. Irradiation with blue light under H2 released the free heterocycle and regenerated the piano-stool iridium hydride precatalyst, establishing a pathway for catalyst recovery and overall enhanced turnover.
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Affiliation(s)
- Junho Kim
- Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, New Jersey 08544, United States
| | - Yoonsu Park
- Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, New Jersey 08544, United States
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4
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Mei T, Zhang P, Song Z, Wang B, Qu J, Ye S, Yang D. Unusual Hydrogenation Reactivities of a Thiolate-Bridged Dicobalt μ-Nitride Featuring a Bent {Co III-N-Co III} Core. J Am Chem Soc 2023; 145:20578-20587. [PMID: 37674257 DOI: 10.1021/jacs.3c07254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Transition metal nitrides have received considerable attention owing to their crucial roles in nitrogen fixation and nitrogen atom transfer reactions. Compared to the early and middle transition metals, it is much more challenging to access late transition metal nitrides, especially cobalt in group 9. So far, only a handful of cobalt nitrides have been reported; consequently, their hydrogenation reactivity is largely unexplored. Herein, we present a structurally and spectroscopically well-characterized thiolate-bridged dicobalt μ-nitride [Cp*CoIII(μ-SAd)(μ-N)CoIIICp*] (2) featuring a bent {CoIII(μ-N)CoIII} core. Remarkably, complex 2 can realize not only direct hydrogenation of nitride to amide but also stepwise N-H bond formation from nitride to ammonia. Specifically, 2 can facilely activate dihydrogen (H2) at mild conditions to generate a dicobalt μ-amide [Cp*CoII(μ-SAd)(μ-NH2)CoIICp*] (4) via an unusual mechanism of two-electron oxidation of H2 as proposed by computational studies; in the presence of protons (H+) and electrons, nitride 2 can convert to dicobalt μ-imide [Cp*CoIII(μ-SAd)(μ-NH)CoIIICp*][BPh4] (3[BPh4]) and to CoIICoII μ-amide 4, and finally release ammonia. In contrast to 2, the only other structurally characterized dicobalt μ-nitride Na(THF)4{[(ketguan)CoIII(N3)]2(μ-N)} (ketguan = [(tBu2CN)C(NDipp)2]-, Dipp = 2,6-diisopropylphenyl) (e) that possesses a linear {CoIII(μ-N)CoIII} moiety cannot directly react with H2 or H+. Further in-depth electronic structure analyses shed light on how the varying geometries of the {CoIII(μ-N)CoIII} moieties in 2 and e, bent vs linear, impart their disparate reactivities.
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Affiliation(s)
- Tao Mei
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Peng Zhang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zihe Song
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Baomin Wang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jingping Qu
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
- State Key Laboratory of Bioreactor Engineering, Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Dawei Yang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
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5
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Park Y, Zhong H, Pabst TP, Kim J, Chirik PJ. Pentamethylcyclopentadienyl Metalloradical Iron Complexes Containing Redox Noninnocent α-Diimine-Type Ligands: Synthesis, Molecular, and Electronic Structures. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Affiliation(s)
- Yoonsu Park
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Hongyu Zhong
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Tyler P. Pabst
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Junho Kim
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J. Chirik
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
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6
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Jia F, Zhang B. Computational Mechanism Investigation of C=C Bond Hydrogenation Catalyzed by Rhodium Hydride. Chemphyschem 2023; 24:e202200562. [PMID: 36148802 DOI: 10.1002/cphc.202200562] [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: 07/29/2022] [Revised: 09/15/2022] [Indexed: 02/03/2023]
Abstract
The hydrogenation of unsaturated carbons is a commonly used synthetic tool in pharmaceutical and industrial production. Recently, the Norton group realized highly selective hydrogenation of C=C bonds catalyzed by a rhodium hydride. Despite the great efforts made by experimentalists, details regarding the mechanism remained unclear. In this work, detailed DFT calculations were carried out to elucidate the principal features of this transformation. For enones we find that two possible competing mechanisms proposed by the experimental groups are computationally excluded, our proposed alternative mechanism with a total barrier of 20.0 kcal mol-1 is theoretically feasible, solvent methanol to also plays a crucial role in assisting β-hydrogenation in addition to being the hydrogen source for α-hydrogenation, and the cross-polarization of the substrate enone-conjugated system to result in an enhanced charge density of the α-carbon, which favors being hydrogenated first. For isolated alkenes, neither of the two possible competing mechanisms can be excluded computationally and which carbon atom is first hydrogenated depends on the electronic properties of the substrate itself. The combination of rhodium and C=C bonds changes the electronic properties of H on the rhodium hydride and enhances its hydrogenation activity.
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Affiliation(s)
- Feiyun Jia
- School of Pharmacy, North Sichuan Medical College, 55 Dongshun Road, 637100, Nanchong, Sichuan, P. R. China
| | - Bo Zhang
- School of Pharmacy, North Sichuan Medical College, 55 Dongshun Road, 637100, Nanchong, Sichuan, P. R. China
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7
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Xin X, Douair I, Zhao Y, Wang S, Maron L, Zhu C. Dinitrogen cleavage and hydrogenation to ammonia with a uranium complex. Natl Sci Rev 2023; 10:nwac144. [PMID: 36950222 PMCID: PMC10026940 DOI: 10.1093/nsr/nwac144] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/12/2022] [Accepted: 07/12/2022] [Indexed: 11/14/2022] Open
Abstract
The Haber-Bosch process produces ammonia (NH3) from dinitrogen (N2) and dihydrogen (H2), but requires high temperature and pressure. Before iron-based catalysts were exploited in the current industrial Haber-Bosch process, uranium-based materials served as effective catalysts for production of NH3 from N2. Although some molecular uranium complexes are known to be capable of combining with N2, further hydrogenation with H2 forming NH3 has not been reported to date. Here, we describe the first example of N2 cleavage and hydrogenation with H2 to NH3 with a molecular uranium complex. The N2 cleavage product contains three uranium centers that are bridged by three imido μ 2-NH ligands and one nitrido μ 3-N ligand. Labeling experiments with 15N demonstrate that the nitrido ligand in the product originates from N2. Reaction of the N2-cleaved complex with H2 or H+ forms NH3 under mild conditions. A synthetic cycle has been established by the reaction of the N2-cleaved complex with trimethylsilyl chloride. The isolation of this trinuclear imido-nitrido product implies that a multi-metallic uranium assembly plays an important role in the activation of N2.
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Affiliation(s)
- Xiaoqing Xin
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Iskander Douair
- LPCNO, CNRS and INSA, Université Paul Sabatier, Toulouse 31077, France
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Shuao Wang
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
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8
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Catalytic nitrogen fixation using visible light energy. Nat Commun 2022; 13:7263. [PMID: 36456553 PMCID: PMC9715552 DOI: 10.1038/s41467-022-34984-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/15/2022] [Indexed: 12/05/2022] Open
Abstract
The synthesis of ammonia from atmospheric dinitrogen, nitrogen fixation, is one of the essential reactions for human beings. Because the current industrial nitrogen fixation depends on dihydrogen produced from fossil fuels as raw material, the development of a nitrogen fixation reaction that relies on the energy provided by renewable energy, such as visible light, is an important research goal from the viewpoint of sustainable chemistry. Herein, we establish an iridium- and molybdenum-catalysed process for synthesizing ammonia from dinitrogen under ambient reaction conditions and visible light irradiation. In this reaction system, iridium complexes and molybdenum triiodide complexes bearing N-heterocyclic carbene-based pincer ligands act as cooperative catalysts to activate 9,10-dihydroacridine and dinitrogen, respectively. The reaction of dinitrogen with 9,10-dihydroacridine is not thermodynamically favoured, and it only takes place under visible light irradiation. Therefore, the described reaction system is one that affords visible light energy-driven ammonia formation from dinitrogen catalytically.
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9
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Bora D, Gayen FR, Saha B. Ammonia from dinitrogen at ambient conditions by organometallic catalysts. RSC Adv 2022; 12:33567-33583. [PMID: 36505716 PMCID: PMC9682445 DOI: 10.1039/d2ra06156b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/15/2022] [Indexed: 11/24/2022] Open
Abstract
Fixation of atmospheric dinitrogen in plants by [Mo-Fe] cofactor of nitrogenase enzyme takes place efficiently under atmospheric pressure and normal temperature. In search for an alternative methodology for the highly energy intensive Haber-Bosch process, design and synthesis of highly efficient inorganic and organometallic complexes by mimicking the structure and function of [Mo-Fe] cofactor system is highly desirable for ammonia synthesis from dinitrogen. An ideal catalyst for ammonia synthesis should effectively catalyse the reduction of dinitrogen in the presence of a proton source under mild to moderate conditions, and thereby, significantly reducing the cost of ammonia production and increasing the energy efficacy of the process. In the light of current research, it is evident that there is a plenty of scope for the development and enhanced performance of the inorganic and organometallic catalysts for ammonia synthesis under ambient temperature and pressure. The review furnishes a comprehensive outlook of numerous organometallic catalysts used in the synthesis of ammonia from dinitrogen in the past few decades.
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Affiliation(s)
- Debashree Bora
- Advanced Materials Group, Materials Sciences and Technology Division, CSIR-North East Institute of Science and TechnologyJorhatAssam-785006India,Academy of Scientific and Innovative Research (AcSIR)Ghaziabad-201002India
| | - Firdaus Rahaman Gayen
- Advanced Materials Group, Materials Sciences and Technology Division, CSIR-North East Institute of Science and TechnologyJorhatAssam-785006India,Academy of Scientific and Innovative Research (AcSIR)Ghaziabad-201002India
| | - Biswajit Saha
- Advanced Materials Group, Materials Sciences and Technology Division, CSIR-North East Institute of Science and TechnologyJorhatAssam-785006India,Academy of Scientific and Innovative Research (AcSIR)Ghaziabad-201002India
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10
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Kim S, Kim J, Zhong H, Panetti GB, Chirik PJ. Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand. J Am Chem Soc 2022; 144:20661-20671. [DOI: 10.1021/jacs.2c07800] [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)
- Sangmin Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Junho Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Hongyu Zhong
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Grace B. Panetti
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J. Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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11
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Martelino D, Mahato S, VandeVen W, Hein NM, Clarke RM, MacNeil GA, Thomas F, Storr T. Chromium Nitride Umpolung Tuned by the Locus of Oxidation. J Am Chem Soc 2022; 144:11594-11607. [PMID: 35749669 DOI: 10.1021/jacs.2c01840] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxidation of a series of CrV nitride salen complexes (CrVNSalR) with different para-phenolate substituents (R = CF3, tBu, NMe2) was investigated to determine how the locus of oxidation (either metal or ligand) dictates reactivity at the nitride. Para-phenolate substituents were chosen to provide maximum variation in the electron-donating ability of the tetradentate ligand at a site remote from the metal coordination sphere. We show that one-electron oxidation affords CrVI nitrides ([CrVINSalR]+; R = CF3, tBu) and a localized CrV nitride phenoxyl radical for the more electron-donating NMe2 substituent ([CrVNSalNMe2]•+). The facile nitride homocoupling observed for the MnVI analogues was significantly attenuated for the CrVI complexes due to a smaller increase in nitride character in the M≡N π* orbitals for Cr relative to Mn. Upon oxidation, both the calculated nitride natural population analysis (NPA) charge and energy of molecular orbitals associated with the {Cr≡N} unit change to a lesser extent for the CrV ligand radical derivative ([CrVNSalNMe2]•+) in comparison to the CrVI derivatives ([CrVINSalR]+; R = CF3, tBu). As a result, [CrVNSalNMe2]•+ reacts with B(C6F5)3, thus exhibiting similar nucleophilic reactivity to the neutral CrV nitride derivatives. In contrast, the CrVI derivatives ([CrVINSalR]+; R = CF3, tBu) act as electrophiles, displaying facile reactivity with PPh3 and no reaction with B(C6F5)3. Thus, while oxidation to the ligand radical does not change the reactivity profile, metal-based oxidation to CrVI results in umpolung, a switch from nucleophilic to electrophilic reactivity at the terminal nitride.
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Affiliation(s)
- Diego Martelino
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Samyadeb Mahato
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Warren VandeVen
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Nicholas M Hein
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Ryan M Clarke
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Gregory A MacNeil
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Fabrice Thomas
- Univ. Grenoble Alpes, CNRS, DCM, F-38000 Grenoble, France
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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12
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Park Y, Tian L, Kim S, Pabst TP, Kim J, Scholes GD, Chirik PJ. Visible-Light-Driven, Iridium-Catalyzed Hydrogen Atom Transfer: Mechanistic Studies, Identification of Intermediates, and Catalyst Improvements. JACS AU 2022; 2:407-418. [PMID: 35252990 PMCID: PMC8889617 DOI: 10.1021/jacsau.1c00460] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 06/14/2023]
Abstract
The harvesting of visible light is a powerful strategy for the synthesis of weak chemical bonds involving hydrogen that are below the thermodynamic threshold for spontaneous H2 evolution. Piano-stool iridium hydride complexes are effective for the blue-light-driven hydrogenation of organic substrates and contra-thermodynamic dearomative isomerization. In this work, a combination of spectroscopic measurements, isotopic labeling, structure-reactivity relationships, and computational studies has been used to explore the mechanism of these stoichiometric and catalytic reactions. Photophysical measurements on the iridium hydride catalysts demonstrated the generation of long-lived excited states with principally metal-to-ligand charge transfer (MLCT) character. Transient absorption spectroscopic studies with a representative substrate, anthracene revealed a diffusion-controlled dynamic quenching of the MLCT state. The triplet state of anthracene was detected immediately after the quenching events, suggesting that triplet-triplet energy transfer initiated the photocatalytic process. The key role of triplet anthracene on the post-energy transfer step was further demonstrated by employing photocatalytic hydrogenation with a triplet photosensitizer and a HAT agent, hydroquinone. DFT calculations support a concerted hydrogen atom transfer mechanism in lieu of stepwise electron/proton or proton/electron transfer pathways. Kinetic monitoring of the deactivation channel established an inverse kinetic isotope effect, supporting reversible C(sp2)-H reductive coupling followed by rate-limiting ligand dissociation. Mechanistic insights enabled design of a piano-stool iridium hydride catalyst with a rationally modified supporting ligand that exhibited improved photostability under blue light irradiation. The complex also provided improved catalytic performance toward photoinduced hydrogenation with H2 and contra-thermodynamic isomerization.
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13
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Léonard NG, Chantarojsiri T, Ziller JW, Yang JY. Cationic Effects on the Net Hydrogen Atom Bond Dissociation Free Energy of High-Valent Manganese Imido Complexes. J Am Chem Soc 2022; 144:1503-1508. [PMID: 35041788 PMCID: PMC9118977 DOI: 10.1021/jacs.1c09583] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Local electric fields can alter energy landscapes to impart enhanced reactivity in enzymes and at surfaces. Similar fields can be generated in molecular systems using charged functionalities. Manganese(V) salen nitrido complexes (salen = N,N'-ethylenebis(salicylideneaminato)) appended with a crown ether unit containing Na+ (1-Na), K+, (1-K), Ba2+ (1-Ba), Sr2+ (1-Sr), La3+ (1-La), or Eu3+ (1-Eu) cation were investigated to determine the effect of charge on pKa, E1/2, and the net bond dissociation free energy (BDFE) of N-H bonds. The series, which includes the manganese(V) salen nitrido without an appended crown, spans 4 units of charge. Bounds for the pKa values of the transient imido complexes were used with the Mn(VI/V) reduction potentials to calculate the N-H BDFEs of the imidos in acetonitrile. Despite a span of >700 mV and >9 pKa units across the series, the hydrogen atom BDFE only spans ∼6 kcal/mol (between 73 and 79 kcal/mol). These results suggest that the incorporation of cationic functionalities is an effective strategy for accessing wide ranges of reduction potentials and pKa values while minimally affecting the BDFE, which is essential to modulating electron, proton, or hydrogen atom transfer pathways.
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Affiliation(s)
- Nadia G Léonard
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Teera Chantarojsiri
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Joseph W Ziller
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Jenny Y Yang
- Department of Chemistry, University of California, Irvine, California 92697, United States
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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14
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Zhang Y, Zhao J, Yang D, Wang B, Zhou Y, Wang J, Chen H, Mei T, Ye S, Qu J. A thiolate-bridged Fe IVFe IV μ-nitrido complex and its hydrogenation reactivity toward ammonia formation. Nat Chem 2022; 14:46-52. [PMID: 34949791 DOI: 10.1038/s41557-021-00852-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 11/02/2021] [Indexed: 11/09/2022]
Abstract
Iron nitrides are key intermediates in biological nitrogen fixation and the industrial Haber-Bosch process, used to form ammonia from dinitrogen. However, the proposed successive conversion of nitride to ammonia remains elusive. In this regard, the search for well-described multi-iron nitrido model complexes and investigations on controlling their reactivity towards ammonia formation have long been of great challenge and importance. Here we report a well-defined thiolate-bridged FeIVFeIV μ-nitrido complex featuring an uncommon bent Fe-N-Fe moiety. Remarkably, this complex shows excellent reactivity toward hydrogenation with H2 at ambient conditions, forming ammonia in high yield. Combined experimental and computational studies demonstrate that a thiolate-bridged FeIIIFeIII μ-amido complex is a key intermediate, which is generated through an unusual two-electron oxidation of H2. Moreover, ammonia production was also realized by treating this diiron μ-nitride with electrons and water as a proton source.
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Affiliation(s)
- Yixin Zhang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China
| | - Jinfeng Zhao
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China
| | - Dawei Yang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China
| | - Baomin Wang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China
| | - Yuhan Zhou
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China
| | - Junhu Wang
- Mössbauer Effect Data Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People's Republic of China
| | - Hui Chen
- CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Tao Mei
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany. .,State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People's Republic of China.
| | - Jingping Qu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, People's Republic of China. .,State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China.
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15
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Hein NM, MacNeil GA, Storr T. Elaboration on the Electronics of Salen Manganese Nitrides: Investigations into Alkoxy-Substituted Ligand Scaffolds. Inorg Chem 2021; 60:16895-16905. [PMID: 34719930 DOI: 10.1021/acs.inorgchem.1c02668] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ligand electronics of salen manganese nitride complexes directly influence the locus of oxidation and, thus, the reactivity of the resulting oxidized species. This work investigates the influence of tert-butoxy, isopropoxy, and methoxy substituents on the electronics of salen manganese nitride species and includes the first documentation of the para Hammett value for the tert-butoxy substituent (σpara = -0.13 ± 0.03). Each alkoxy-substituted complex undergoes metal-based oxidation to form manganese(VI), and the kinetics of bimolecular homocoupling to form N2 were assessed by cyclic voltammetry. Bis-oxidation of the manganese complexes was investigated at low temperature using cyclic voltammery and UV-vis-near-IR spectroscopy, and in combination with theoretical calculations, plausible electronic structures of the dications are provided.
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Affiliation(s)
- Nicholas M Hein
- Department of Chemistry, Simon Fraser University (SFU), 8888 University Drive, Burnaby, British Columbia V5A 1S4, Canada
| | - Gregory A MacNeil
- Department of Chemistry, Simon Fraser University (SFU), 8888 University Drive, Burnaby, British Columbia V5A 1S4, Canada
| | - Tim Storr
- Department of Chemistry, Simon Fraser University (SFU), 8888 University Drive, Burnaby, British Columbia V5A 1S4, Canada
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16
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Visible light enables catalytic formation of weak chemical bonds with molecular hydrogen. Nat Chem 2021; 13:969-976. [PMID: 34253889 DOI: 10.1038/s41557-021-00732-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/13/2021] [Indexed: 02/08/2023]
Abstract
The synthesis of weak chemical bonds at or near thermodynamic potential is a fundamental challenge in chemistry, with applications ranging from catalysis to biology to energy science. Proton-coupled electron transfer using molecular hydrogen is an attractive strategy for synthesizing weak element-hydrogen bonds, but the intrinsic thermodynamics presents a challenge for reactivity. Here we describe the direct photocatalytic synthesis of extremely weak element-hydrogen bonds of metal amido and metal imido complexes, as well as organic compounds with bond dissociation free energies as low as 31 kcal mol-1. Key to this approach is the bifunctional behaviour of the chromophoric iridium hydride photocatalyst. Activation of molecular hydrogen occurs in the ground state and the resulting iridium hydride harvests visible light to enable spontaneous formation of weak chemical bonds near thermodynamic potential with no by-products. Photophysical and mechanistic studies corroborate radical-based reaction pathways and highlight the uniqueness of this photodriven approach in promoting new catalytic chemistry.
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17
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Bailey GA, Agapie T. Terminal Mo Carbide and Carbyne Reactivity: H2 Cleavage, B–C Bond Activation, and C–C Coupling. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00336] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Gwendolyn A. Bailey
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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18
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Gu Y, Norton JR, Salahi F, Lisnyak VG, Zhou Z, Snyder SA. Highly Selective Hydrogenation of C═C Bonds Catalyzed by a Rhodium Hydride. J Am Chem Soc 2021; 143:9657-9663. [PMID: 34142805 DOI: 10.1021/jacs.1c04683] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Under mild conditions (room temperature, 80 psi of H2) Cp*Rh(2-(2-pyridyl)phenyl)H catalyzes the selective hydrogenation of the C═C bond in α,β-unsaturated carbonyl compounds, including natural product precursors with bulky substituents in the β position and substrates possessing an array of additional functional groups. It also catalyzes the hydrogenation of many isolated double bonds. Mechanistic studies reveal that no radical intermediates are involved, and the catalyst appears to be homogeneous, thereby affording important complementarity to existing protocols for similar hydrogenation processes.
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Affiliation(s)
- Yiting Gu
- Department of Chemistry, Columbia University, 3000 Broadway, New York City, New York 10027, United States
| | - Jack R Norton
- Department of Chemistry, Columbia University, 3000 Broadway, New York City, New York 10027, United States
| | - Farbod Salahi
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Vladislav G Lisnyak
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Zhiyao Zhou
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Scott A Snyder
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
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19
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Zhao YX, Zhao XG, Yang Y, Ruan M, He SG. Rhodium chemistry: A gas phase cluster study. J Chem Phys 2021; 154:180901. [PMID: 34241019 DOI: 10.1063/5.0046529] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Due to the extraordinary catalytic activity in redox reactions, the noble metal, rhodium, has substantial industrial and laboratory applications in the production of value-added chemicals, synthesis of biomedicine, removal of automotive exhaust gas, and so on. The main drawback of rhodium catalysts is its high-cost, so it is of great importance to maximize the atomic efficiency of the precious metal by recognizing the structure-activity relationship of catalytically active sites and clarifying the root cause of the exceptional performance. This Perspective concerns the significant progress on the fundamental understanding of rhodium chemistry at a strictly molecular level by the joint experimental and computational study of the reactivity of isolated Rh-based gas phase clusters that can serve as ideal models for the active sites of condensed-phase catalysts. The substrates cover the important organic and inorganic molecules including CH4, CO, NO, N2, and H2. The electronic origin for the reactivity evolution of bare Rhx q clusters as a function of size is revealed. The doping effect and support effect as well as the synergistic effect among heteroatoms on the reactivity and product selectivity of Rh-containing species are discussed. The ingenious employment of diverse experimental techniques to assist the Rh1- and Rh2-doped clusters in catalyzing the challenging endothermic reactions is also emphasized. It turns out that the chemical behavior of Rh identified from the gas phase cluster study parallels the performance of condensed-phase rhodium catalysts. The mechanistic aspects derived from Rh-based cluster systems may provide new clues for the design of better performing rhodium catalysts including the single Rh atom catalysts.
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Affiliation(s)
- Yan-Xia Zhao
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xi-Guan Zhao
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yuan Yang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Man Ruan
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Sheng-Gui He
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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20
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Barluzzi L, Hsueh FC, Scopelliti R, Atkinson BE, Kaltsoyannis N, Mazzanti M. Synthesis, structure, and reactivity of uranium(vi) nitrides. Chem Sci 2021; 12:8096-8104. [PMID: 34194699 PMCID: PMC8208130 DOI: 10.1039/d1sc01796a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/30/2021] [Indexed: 12/29/2022] Open
Abstract
Uranium nitride compounds are important molecular analogues of uranium nitride materials such as UN and UN2 which are effective catalysts in the Haber-Bosch synthesis of ammonia, but the synthesis of molecular nitrides remains a challenge and studies of the reactivity and of the nature of the bonding are poorly developed. Here we report the synthesis of the first nitride bridged uranium complexes containing U(vi) and provide a unique comparison of reactivity and bonding in U(vi)/U(vi), U(vi)/U(v) and U(v)/U(v) systems. Oxidation of the U(v)/U(v) bis-nitride [K2{U(OSi(O t Bu)3)3(μ-N)}2], 1, with mild oxidants yields the U(v)/U(vi) complexes [K{U(OSi(O t Bu)3)3(μ-N)}2], 2 and [K2{U(OSi(O t Bu)3)3}2(μ-N)2(μ-I)], 3 while oxidation with a stronger oxidant ("magic blue") yields the U(vi)/U(vi) complex [{U(OSi(O t Bu)3)3}2(μ-N)2(μ-thf)], 4. The three complexes show very different stability and reactivity, with N2 release observed for complex 4. Complex 2 undergoes hydrogenolysis to yield imido bridged [K2{U(OSi(O t Bu)3)3(μ-NH)}2], 6 and rare amido bridged U(iv)/U(iv) complexes [{U(OSi(O t Bu)3)3}2(μ-NH2)2(μ-thf)], 7 while no hydrogenolysis could be observed for 4. Both complexes 2 and 4 react with H+ to yield quantitatively NH4Cl, but only complex 2 reacts with CO and H2. Differences in reactivity can be related to significant differences in the U-N bonding. Computational studies show a delocalised bond across the U-N-U for 1 and 2, but an asymmetric bonding scheme is found for the U(vi)/U(vi) complex 4 which shows a U-N σ orbital well localised to U[triple bond, length as m-dash]N and π orbitals which partially delocalise to form the U-N single bond with the other uranium.
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Affiliation(s)
- Luciano Barluzzi
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Fang-Che Hsueh
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Rosario Scopelliti
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Benjamin E Atkinson
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Nikolas Kaltsoyannis
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Marinella Mazzanti
- Insititut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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21
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Margulieux GW, Kim S, Chirik PJ. Determination of the N-H Bond Dissociation Free Energy in a Pyridine(diimine)molybdenum Complex Prepared by Proton-Coupled Electron Transfer. Inorg Chem 2020; 59:15394-15401. [PMID: 33016073 DOI: 10.1021/acs.inorgchem.0c02382] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pyridine(diimine)molybdenum bis(imido) complex (iPrPDI)Mo(═NTol)2 (Tol = 4-methylphenyl) was synthesized by the addition of 2 equiv of 4-methylphenylazide to the corresponding molybdenum benzene derivative, (iPrPDI)Mo(η6-C6H6) [iPrPDI = 2,6-(2,6-iPr2C6H3N═CMe)2C5H3N]. Protonation of (iPrPDI)Mo(═NTol)2 with 2,6-lutinidum triflate yielded a cationic molybdenum amido complex, [(iPrPDI)Mo(NHTol)(═NTol)][OTf], which was further transformed into the neutral molybdenum amido (iPrPDI)Mo(NHTol)(═NTol) by reduction with zinc powder. A series of spectroscopic, synthetic, and pKa determination studies along with electrochemical measurements by the protonation-reduction pathway were used to establish an N-H bond dissociation free energy (BDFE) between 65 and 69 kcal/mol for the molybdenum imido-amido compound, (iPrPDI)Mo(NHTol)(═NTol). Full-molecule density functional theory studies provided a computed value of 61 kcal/mol. By contrast, reduction of (iPrPDI)Mo(═NTol)2 with KC8 afforded the corresponding anionic molybdenum complex K[(iPrPDI)Mo(═NTol)2], which has a potassium cation intercalated with the pyridine and tolyl groups. Protonation of K[(iPrPDI)Mo(═NTol)2] with the weak amidinium acid [TBD(H)][BArF24] (TBD = triazabicyclodecene; BArF24 = B[3,5-(CF3)2C6H3]4) also produced the neutral molybdenum amido complex (iPrPDI)Mo(NHTol)(═NTol). Measurement of the pKa and oxidation potential of K[(iPrPDI)Mo(═NTol)2] provided a range of 69-73 kcal/mol for the N-H BDFE of (iPrPDI)Mo(NHTol)(═NTol), in good agreement with the protonation-reduction route and completing the square scheme. The similar pKa and redox potentials obtained from each pathway demonstrate that both sequences are energetically feasible for proton-coupled electron-transfer (PCET) events. This study on the determination of N-H BDFE of the molybdenum amido complex renders fundamental insight into the N2 reduction cycle by PCET.
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Affiliation(s)
- Grant W Margulieux
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Sangmin Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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