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Kumar M, Gupta MK, Ansari M, Ansari A. C-H bond activation by high-valent iron/cobalt-oxo complexes: a quantum chemical modeling approach. Phys Chem Chem Phys 2024; 26:4349-4362. [PMID: 38235511 DOI: 10.1039/d3cp05866b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
High-valent metal-oxo species serve as key intermediates in the activation of inert C-H bonds. Here, we present a comprehensive DFT analysis of the parameters that have been proposed as influencing factors in modeled high-valent metal-oxo mediated C-H activation reactions. Our approach involves utilizing DFT calculations to explore the electronic structures of modeled FeIVO (species 1) and CoIVO ↔ CoIII-O˙ (species 2), scrutinizing their capacity to predict improved catalytic activity. DFT and DLPNO-CCSD(T) calculations predict that the iron-oxo species possesses a triplet as the ground state, while the cobalt-oxo has a doublet as the ground state. Furthermore, we have investigated the mechanistic pathways for the first C-H bond activation, as well as the desaturation of the alkanes. The mechanism was determined to be a two-step process, wherein the first hydrogen atom abstraction (HAA) represents the rate-limiting step, involving the proton-coupled electron transfer (PCET) process. However, we found that the second HAA step is highly exothermic for both species. Our calculations suggest that the iron-oxo species (Fe-O = 1.672 Å) exhibit relatively sluggish behavior compared to the cobalt-oxo species (Co-O = 1.854 Å) in C-H bond activation, attributed to a weak metal-oxygen bond. MO, NBO, and deformation energy analysis reveal the importance of weakening the M-O bond in the cobalt species, thereby reducing the overall barrier to the reaction. This catalyst was found to have a C-H activation barrier relatively smaller than that previously reported in the literature.
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Affiliation(s)
- Manjeet Kumar
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Manoj Kumar Gupta
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Mursaleem Ansari
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
| | - Azaj Ansari
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
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Wang S, Sun D, Wu Z, Zhao Y, Wang Y. The elusive reaction mechanism of Mn(II)-mediated benzylic oxidation of alkylarene by H 2O 2: a gem-diol mechanism or a dual hydrogen abstraction mechanism? Dalton Trans 2023. [PMID: 37997638 DOI: 10.1039/d3dt02943c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
The direct oxygenation of alkylarenes at the benzylic position employing bioinspired nonheme catalysts has emerged as a promising strategy for the production of bioactive arene ketone scaffolds in drugs. However, the structure-activity relationship of the active species and the mechanism of these reactions remain elusive. Herein, the reaction mechanism of the Mn(II)-mediated benzylic oxygenation of phenylbutanoic acid (PBA) to 4-oxo-4-phenylbutyric acid (4-oxo-PBA) by H2O2 was investigated using density functional theory calculations. The calculated results demonstrated that the MnIII-OOH species (1) is a sluggish oxidant and needs to be converted to a high-valent manganese-oxo species (2). The conversion of PBA to 4-oxo-PBA by 2 occurs via the consecutive hydroxylation of PBA to 4-hydroxyl-4-phenylbutyric acid (4-OH-PBA) and the alcohol oxidation of 4-OH-PBA to 4-oxo-PBA. The hydroxylation of PBA proceeds via a novel hydride transfer/hydroxyl-rebound mechanism and the alcohol oxidation of 4-OH-PBA occurs via three pathways (gem-diol, dual hydrogen abstraction (DHA), and reversed-DHA pathways). The regio-selectivity of benzylic oxidations was caused by a strong π-π stacking interaction between the pyridine ring of the nonheme ligand and the phenyl ring of the substrate. These mechanistic findings enrich the knowledge of biomimetic alcohol oxidations and play a positive role in the rational design of new non-heme catalysts.
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Affiliation(s)
- Shoujun Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Zhimin Wu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Yong Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
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Monika, Kumar M, Somi, Sarkar A, Gupta MK, Ansari A. Theoretical study of the formation of metal-oxo species of the first transition series with the ligand 14-TMC: driving factors of the "Oxo Wall". Dalton Trans 2023; 52:14160-14169. [PMID: 37750348 DOI: 10.1039/d3dt02109b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Terminal metal-oxo species of the early transition metal series are well known, whereas those for the late transition series are rare, and this is related to the "Oxo Wall". Here, we have undertaken a theoretical study on the formation of metal-oxo species from the metal hydroperoxo species of the 3d series (Cr, Mn, Fe, Co, Ni, and Cu) with the ligand 14-TMC (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) via O⋯O bond cleavage. DFT calculations reveal that the barrier for O⋯O bond cleavage is higher with the late transition metals (Co, Ni, and Cu) than the early transition metals (Cr, Mn, and Fe), and the formed late metal-oxo species are also thermodynamically less stable. The higher barrier may be due to electronic repulsion because of the pairing of d electrons. In the late transition metal series, the electron goes into an antibonding orbital, which decreases the bond order and hence decreases the possibility of metal-oxo formation. Computed structural parameters and spin densities suggest that valence tautomerism occurs in the late transition metal-oxo species which remain as a metal-oxyl. Our findings support the concept of the "Oxo Wall".
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Affiliation(s)
- Monika
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Manjeet Kumar
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Somi
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Arup Sarkar
- Department of Chemistry, The University of Chicago 5735 South Ellis Avenue, Chicago, IL 60637, USA
| | - Manoj Kumar Gupta
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Azaj Ansari
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
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Zhou A, Li XX, Sun D, Cao X, Wu Z, Chen H, Zhao Y, Nam W, Wang Y. Theoretical investigation on the elusive structure-activity relationship of bioinspired high-valence nickel-halogen complexes in oxidative fluorination reactions. Dalton Trans 2023; 52:1977-1988. [PMID: 36691931 DOI: 10.1039/d2dt03212k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Very recently, bioinspired high-valence metal-halogen complexes have been proven to be competent oxidants in the C-H bond activation and heteroatom dihalogenation reactions. However, the structure-activity relationship of such active species and the reaction mechanisms of oxidations mediated by these oxidants are still elusive. In this study, density functional theory (DFT) calculations were performed to systematically study the oxidizing ability of the high-valence NiIII-X (X = F and Cl) complexes Et4N[NiIII(Cl/F)(L)], (1Cl/F, Et = ethyl, L = N,N'-(2,6-dimethylphenyl)-2,6-pyridinedicarboxamide), such as the reaction mechanism of fluorination of 1,4-cyclohexadiene (CHD) by 1F in the presence of AgF and the reaction mechanism of difluorination of triphenyl phosphine (PPh3) by 1F. All calculated results fit well with the experiments and present new mechanistic findings. The C-H bond activation by the high-valence nickel(III)-halogen complexes was found to proceed via a hydrogen-atom transfer (HAT) mechanism by analysis of the molecular orbitals of the transition states. C-H bond activation by 1F takes a Ni-F-H angle of ca. 180°, whereas that by 1Cl takes an angle of ca. 120° on the transition states. These results indicate that the exchange-enhanced reactivity is responsible for the dramatic oxidative difference between these two oxidants. The role of AgF in C-H fluorination of CHD by 1F is proposed to act as a Lewis acid adduct, AgF-binding Ni(III)-fluorine complex 1F-Ag-F, which acts both as an oxidant in C-H bond activation and as a fluorine donor in the fluorination step. A cooperative oxidation mechanism involving two 1F oxidants was proposed for the difluorination of PPh3 by 1F. These theoretical findings will enrich the knowledge of high-valence metal-halogen chemistry and play a positive role in the rational design of new catalysts.
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Affiliation(s)
- Anran Zhou
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China. .,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Xiao-Xi Li
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Sciences, Shandong University, Qingdao 266237, China
| | - Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China. .,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Xuanyu Cao
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Zhimin Wu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China. .,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Huanhuan Chen
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China. .,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China. .,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.
| | - Yong Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China. .,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
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Malik DD, Lee Y, Nam W. Identification of a cobalt(
IV
)–oxo intermediate as an active oxidant in catalytic oxidation reactions. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Deesha D. Malik
- Department of Chemistry and Nano Science Ewha Womans University Seoul South Korea
| | - Yong‐Min Lee
- Department of Chemistry and Nano Science Ewha Womans University Seoul South Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science Ewha Womans University Seoul South Korea
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