1
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Gera R, De P, Singh KK, Jannuzzi SAV, Mohanty A, Velasco L, Kulbir, Kumar P, Marco JF, Nagarajan K, Pecharromán C, Rodríguez-Pascual PM, DeBeer S, Moonshiram D, Gupta SS, Dasgupta J. Trapping an Elusive Fe(IV)-Superoxo Intermediate Inside a Self-Assembled Nanocage in Water at Room Temperature. J Am Chem Soc 2024; 146:21729-21741. [PMID: 39078020 DOI: 10.1021/jacs.4c05849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Molecular cavities that mimic natural metalloenzymes have shown the potential to trap elusive reaction intermediates. Here, we demonstrate the formation of a rare yet stable Fe(IV)-superoxo intermediate at room temperature subsequent to dioxygen binding at the Fe(III) site of a (Et4N)2[FeIII(Cl)(bTAML)] complex confined inside the hydrophobic interior of a water-soluble Pd6L412+ nanocage. Using a combination of electron paramagnetic resonance, Mössbauer, Raman/IR vibrational, X-ray absorption, and emission spectroscopies, we demonstrate that the cage-encapsulated complex has a Fe(IV) oxidation state characterized by a stable S = 1/2 spin state and a short Fe-O bond distance of ∼1.70 Å. We find that the O2 reaction in confinement is reversible, while the formed Fe(IV)-superoxo complex readily reacts when presented with substrates having weak C-H bonds, highlighting the lability of the O-O bond. We envision that such optimally trapped high-valent superoxos can show new classes of reactivities catalyzing both oxygen atom transfer and C-H bond activation reactions.
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Affiliation(s)
- Rahul Gera
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
- Department of Education in Science and Mathematics, Regional Institute of Education - Mysuru, NCERT, Mysuru 570006, India
| | - Puja De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Kundan K Singh
- Chemical Engineering Division, CSIR-National Chemical Laboratory, Pune, Maharashtra 411008, India
- Chemistry Department, Indian Institute of Technology, Dharwad 580007, India
| | - Sergio A V Jannuzzi
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, Mülheim an der Ruhr 45470, Germany
| | - Aisworika Mohanty
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Lucia Velasco
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Kulbir
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India
| | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India
| | - J F Marco
- Instituto de Quimica Fisica Blas Cabrera, Consejo Superior de Investigaciones Científicas, Serrano 119, Madrid 28006, Spain
| | - Kalaivanan Nagarajan
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Carlos Pecharromán
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - P M Rodríguez-Pascual
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Serena DeBeer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, Mülheim an der Ruhr 45470, Germany
| | - Dooshaye Moonshiram
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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2
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Cao Q, Diefenbach M, Maguire C, Krewald V, Muldoon MJ, Hintermair U. Water co-catalysis in aerobic olefin epoxidation mediated by ruthenium oxo complexes. Chem Sci 2024; 15:3104-3115. [PMID: 38425537 PMCID: PMC10901482 DOI: 10.1039/d3sc05516g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/05/2024] [Indexed: 03/02/2024] Open
Abstract
We report the development of a versatile Ru-porphyrin catalyst system which performs the aerobic epoxidation of aromatic and aliphatic (internal) alkenes under mild conditions, with product yields of up to 95% and turnover numbers (TON) up to 300. Water is shown to play a crucial role in the reaction, significantly increasing catalyst efficiency and substrate scope. Detailed mechanistic investigations employing both computational studies and a range of experimental techniques revealed that water activates the RuVI di-oxo complex for alkene epoxidation via hydrogen bonding, stabilises the RuIV mono-oxo intermediate, and is involved in the regeneration of the RuVI di-oxo complex leading to oxygen atom exchange. Distinct kinetics are obtained in the presence of water, and side reactions involved in catalyst deactivation have been identified.
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Affiliation(s)
- Qun Cao
- School of Chemistry and Chemical Engineering, Queen's University Belfast Northern Ireland UK
- Dynamic Reaction Monitoring Facility, Institute for Sustainability, University of Bath UK
| | - Martin Diefenbach
- Theoretical Chemistry, Department of Chemistry, Technische Universität Darmstadt Germany
| | - Calum Maguire
- School of Chemistry and Chemical Engineering, Queen's University Belfast Northern Ireland UK
| | - Vera Krewald
- Theoretical Chemistry, Department of Chemistry, Technische Universität Darmstadt Germany
| | - Mark J Muldoon
- School of Chemistry and Chemical Engineering, Queen's University Belfast Northern Ireland UK
| | - Ulrich Hintermair
- Dynamic Reaction Monitoring Facility, Institute for Sustainability, University of Bath UK
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3
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Majumder P, Basak A, Kuiry H, Sasmal HS, Karak S, Saha P, Chandra B, Sen Gupta S, Banerjee R. Proximity-Enabled Photochemical C-H Functionalization using a Covalent Organic Framework-Confined Fe 2IV-μ-oxo Species in Water. J Am Chem Soc 2023; 145:18855-18864. [PMID: 37587434 DOI: 10.1021/jacs.3c04409] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Water has been recognized as an excellent solvent for maneuvering both the catalytic activity and selectivity, especially in the case of heterogeneous catalysis. However, maintaining the active catalytic species in their higher oxidation states (IV/V) while retaining the catalytic activity and recyclability in water is an enormous challenge. Herein, we have developed a solution to this problem using covalent organic frameworks (COFs) to immobilize the (Et4N)2[FeIII(Cl)bTAML] molecules, taking advantage of the COF's morphology and surface charge. By using the visible light and [CoIII(NH3)5Cl]Cl2 as a sacrificial electron acceptor within the COF, we have successfully generated and stabilized the [(bTAML)FeIV-O-FeIV(bTAML)]- species in water. The COF backbone simultaneously acts as a porous host and a photosensitizer. This is the first time that the photochemically generated Fe2IV-μ-oxo radical cation species has demonstrated high catalytic activity with moderate to high yield for the selective oxidation of the unactivated C-H bonds, even in water. To enhance the catalytic activity and achieve good recyclability, we have developed a TpDPP COF film by transforming the TpDPP COF nanospheres. We have achieved the regio- and stereoselective functionalization of unactivated C-H bonds of alkanes and alkenes (3°:2° = 102:1 for adamantane with the COF film), which is improbable in homogeneous conditions. The film exhibits C-H bond oxidation with higher catalytic yield (32-98%) and a higher degree of selectivity (cis/trans = 74:1; 3°:2° = 100:1 for cis-decalin).
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Affiliation(s)
- Poulami Majumder
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Ananda Basak
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Himangshu Kuiry
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Himadri Sekhar Sasmal
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Suvendu Karak
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Paramita Saha
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, West Bengal, India
| | - Bittu Chandra
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
| | - Rahul Banerjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India
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Liu M, Zhang G. Amorphous Goethite as a Catalyst of Chemoselectivity Epoxidation of Alkenes by Hydrogen Peroxide. RUSS J GEN CHEM+ 2022. [DOI: 10.1134/s1070363222080230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Kuiry H, Das D, Das S, Chakraborty S, Chandra B, Gupta SS. Electrocatalytic alcohol oxidation by a molecular iron complex. Faraday Discuss 2022; 234:42-57. [PMID: 35174376 DOI: 10.1039/d1fd00074h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient electrochemical method for the selective oxidation of alcohols to their corresponding aldehydes/ketones using a biomimetic iron complex, [(bTAML)FeIII-OH2]-, as the redox mediator in an undivided electrochemical cell with inexpensive carbon and nickel electrodes using water as an oxygen source is reported. The substrate scope also includes alcohols that contain O and N heteroatoms in the scaffold, which are well tolerated under these reaction conditions. Mechanistic studies show the involvement of a high-valent FeV(O) species, [(bTAML)FeV(O)]-, formed via PCET (overall 2H+/2e-) from [(bTAML)FeIII-OH2]- at 0.77 V (vs. Fc+/Fc). Moreover, electrokinetic studies of the oxidation of C-H bonds indicate a second-order reaction, with the C-H abstraction by FeV(O) being the rate-determining step. The overall mechanism, studied using linear free energy relationships and radical clocks, indicates a "net hydride" transfer, leading to the oxidation of the alcohol to the corresponding aldehyde or ketone. When the reaction was carried out at pH > 11, the reaction could be carried out at a ∼500 mV lower potential than that at pH 8, albeit with reduced reaction rates. The reactive intermediate involved at pH > 11 is the corresponding one-electron oxidized [(bTAML)FeIV(O)]2- species.
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Affiliation(s)
- Himangshu Kuiry
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India-741246.
| | - Debasree Das
- Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Pune, Maharashtra-411008, India
| | - Soumadip Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India-741246.
| | - Soham Chakraborty
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India-741246.
| | - Bittu Chandra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India-741246.
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India-741246.
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6
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Chandra B, K M H, Pattanayak S, Gupta SS. Oxoiron(v) mediated selective electrochemical oxygenation of unactivated C-H and C[double bond, length as m-dash]C bonds using water as the oxygen source. Chem Sci 2020; 11:11877-11885. [PMID: 34094416 PMCID: PMC8162932 DOI: 10.1039/d0sc03616a] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
An efficient electrochemical method for the selective oxidation of C–H bonds of unactivated alkanes (BDE ≤97 kcal mol−1) and CC bonds of alkenes using a biomimetic iron complex, [(bTAML)FeIII-OH2]−, as the redox mediator in an undivided electrochemical cell with inexpensive carbon and nickel electrodes is reported. The O-atom of water remains the source of O-incorporation in the product formed after oxidation. The products formed upon oxidation of C–H bonds display very high regioselectivity (75 : 1, 3° : 2° for adamantane) and stereo-retention (RC ∼99% for cyclohexane derivatives). The substrate scope includes natural products such as cedryl acetate and ambroxide. For alkenes, epoxides were obtained as the sole product. Mechanistic studies show the involvement of a high-valent oxoiron(v) species, [(bTAML)FeV(O)]− formed via PCET (overall 2H+/2e−) from [(bTAML)FeIII-OH2]− in CPE at 0.80 V (vs. Ag/AgNO3). Moreover, electrokinetic studies for the oxidation of C–H bonds indicate a second-order reaction with the C–H abstraction by oxoiron(v) being the rate-determining step. A biomimetic iron complex-mediated selective and efficient electrochemical oxygenation of unactivated C–H bonds and CC bonds using water as an O-atom source.![]()
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Affiliation(s)
- Bittu Chandra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal India-741246
| | - Hellan K M
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal India-741246
| | - Santanu Pattanayak
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal India-741246
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal India-741246
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7
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Chandra B, De P, Sen Gupta S. Selective oxygenation of unactivated C-H bonds by dioxygen via the autocatalytic formation of oxoiron(v) species. Chem Commun (Camb) 2020; 56:8484-8487. [PMID: 32588843 DOI: 10.1039/d0cc03071f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Selective catalytic oxygenation of unactivated C-H bonds for a series of substrates by dioxygen using iron complexes was performed without the use of a co-reductant. Mechanistic studies indicate that the reaction proceeded via the autocatalytic formation of an oxoiron(v) intermediate, which brings high regioselectivity and stereoretention.
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Affiliation(s)
- Bittu Chandra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
| | - Puja De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
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8
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Panda C, Sarkar A, Sen Gupta S. Coordination chemistry of carboxamide ‘Nx’ ligands to metal ions for bio-inspired catalysis. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213314] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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A Bimetallic Pure Inorganic Framework for Highly Efficient and Selective Photocatalytic Oxidation of Cyclohexene to 2-Cyclohexen-1-ol. Catal Letters 2019. [DOI: 10.1007/s10562-019-02847-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Sheet D, Bera A, Fu Y, Desmecht A, Riant O, Hermans S. Carbon‐Nanotube‐Appended PAMAM Dendrimers Bearing Iron(II) α‐Keto Acid Complexes: Catalytic Non‐Heme Oxygenase Models. Chemistry 2019; 25:9191-9196. [DOI: 10.1002/chem.201901735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/13/2019] [Indexed: 01/20/2023]
Affiliation(s)
- Debobrata Sheet
- Institute of Condensed Matter and Nanosciences/Molecular Chemistry, Materials and Catalysis (IMCN/MOST)UCLouvain Place Louis Pasteur 1 1348 Louvain-la-Neuve Belgium
- Department of ChemistryPresidency University, 86/1 College Street Kolkata 700073 India
| | - Abhijit Bera
- School of Chemical SciencesIndian Association for the Cultivation of Sciences 2A & 2B Raja S C Mullick Road Kolkata 700032 India
| | - Yang Fu
- Institute of Condensed Matter and Nanosciences/Molecular Chemistry, Materials and Catalysis (IMCN/MOST)UCLouvain Place Louis Pasteur 1 1348 Louvain-la-Neuve Belgium
| | - Antonin Desmecht
- Institute of Condensed Matter and Nanosciences/Molecular Chemistry, Materials and Catalysis (IMCN/MOST)UCLouvain Place Louis Pasteur 1 1348 Louvain-la-Neuve Belgium
| | - Olivier Riant
- Institute of Condensed Matter and Nanosciences/Molecular Chemistry, Materials and Catalysis (IMCN/MOST)UCLouvain Place Louis Pasteur 1 1348 Louvain-la-Neuve Belgium
| | - Sophie Hermans
- Institute of Condensed Matter and Nanosciences/Molecular Chemistry, Materials and Catalysis (IMCN/MOST)UCLouvain Place Louis Pasteur 1 1348 Louvain-la-Neuve Belgium
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11
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Sheet D, Bera A, Jana RD, Paine TK. Oxidizing Ability of a Dioxygen-Activating Nonheme Iron(II)-Benzilate Complex Immobilized on Gold Nanoparticles. Inorg Chem 2019; 58:4828-4841. [PMID: 30916560 DOI: 10.1021/acs.inorgchem.8b03288] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
An iron(II)-benzilate complex [(TPASH)FeII(benzilate)]ClO4@C8Au (2) (TPASH = 11-((6-((bis(pyridin-2-ylmethyl)amino)methyl)pyridin-2-yl)methoxy)undecane-1-thiol) immobilized on octanethiol stabilized gold nanoparticles (C8Au) of core diameter less than 5 nm has been prepared to evaluate its reactivity toward O2-dependent oxidations compared to a nonimmobilized complex [(TPA-O-Allyl)FeII(benzilate)]ClO4 (1a) (TPA-O-Allyl = N-((6-(allyloxymethyl)pyridin-2-yl)methyl)(pyridin-2-yl)- N-(pyridin-2-ylmethyl)methanamine). X-ray crystal structure of the nonimmobilized complex 1a reveals a six-coordinate iron(II) center in which the TPA-O-Allyl acts as a pentadentate ligand and the benzilate anion binds in monodentate fashion. Both the complexes (1a and 2) react with dioxygen under ambient conditions to form benzophenone as the sole product through decarboxylation of the coordinated benzilate. Interception studies reveal that a nucleophilic iron-oxygen intermediate is formed in the decarboxylation reaction. The oxidants from both the complexes are able to carry out oxo atom transfer reactions. The immobilized complex 2 not only performs faster decarboxylation but also exhibits enhanced reactivity in oxo atom transfer to sulfides. Importantly, the immobilized complex 2, unlike 1a, displays catalytic turnovers in sulfide oxidation. However, the complexes are not efficient to carry out cis-dihydroxylation of alkenes. Although the immobilized complex yields a slightly higher amount of cis-diol from 1-octene, restricted access of dioxygen and substrates at the coordinatively saturated metal centers of the complexes likely makes the resulting iron-oxygen species less active in oxygen atom transfer to alkenes. The results implicate that surface immobilized nonheme iron complexes containing accessible coordination sites would exhibit better reactivity in O2-dependent oxygenation reactions.
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Affiliation(s)
- Debobrata Sheet
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A & 2B Raja S. C. Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Abhijit Bera
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A & 2B Raja S. C. Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Rahul Dev Jana
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A & 2B Raja S. C. Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Tapan Kanti Paine
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A & 2B Raja S. C. Mullick Road , Jadavpur, Kolkata 700032 , India
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12
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Wang P, Yap GP, Riordan CG. Synthesis, characterization and O2 reactivity of a bioinspired cobalt(II)-catecholate complex. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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13
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Das A, Mandal I, Venkatramani R, Dasgupta J. Ultrafast photoactivation of C─H bonds inside water-soluble nanocages. SCIENCE ADVANCES 2019; 5:eaav4806. [PMID: 30801018 PMCID: PMC6386559 DOI: 10.1126/sciadv.aav4806] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/11/2019] [Indexed: 05/05/2023]
Abstract
Light energy absorbed by molecules can be harnessed to activate chemical bonds with extraordinary speed. However, excitation energy redistribution within various molecular degrees of freedom prohibits bond-selective chemistry. Inspired by enzymes, we devised a new photocatalytic scheme that preorganizes and polarizes target chemical bonds inside water-soluble cationic nanocavities to engineer selective functionalization. Specifically, we present a route to photoactivate weakly polarized sp3 C─H bonds in water via host-guest charge transfer and control its reactivity with aerial O2. Electron-rich aromatic hydrocarbons self-organize inside redox complementary supramolecular cavities to form photoactivatable host-guest charge transfer complexes in water. An ultrafast C─H bond cleavage within ~10 to 400 ps is triggered by visible-light excitation, through a cage-assisted and solvent water-assisted proton-coupled electron transfer reaction. The confinement prolongs the lifetime of the carbon-centered radical to enable a facile yet selective reaction with molecular O2 leading to photocatalytic turnover of oxidized products in water.
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Affiliation(s)
- Ankita Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Imon Mandal
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Ravindra Venkatramani
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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14
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Luo K, Zhao Y, Zhang J, He J, Huang R, Yan S, Lin J, Jin Y. Enantioselective Epoxypyrrolidines via a Tandem Cycloaddition/Autoxidation in Air and Mechanistic Studies. Org Lett 2018; 21:423-427. [PMID: 30588819 DOI: 10.1021/acs.orglett.8b03605] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A tandem cycloaddition/autoxidation reaction between heterocyclic ketene aminals and diazoester in air is described for the enantioselective preparation of epoxypyrrolidines. Notably, the results of mechanistic studies suggest that epoxide was oxidized from an sp3 C-C single bond, which is of mechanistic and practical interest as this protocol may be suitable for constructing other bioactive heterocyclic epoxides.
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Affiliation(s)
- Kaixiu Luo
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Yongqiang Zhao
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Jiawei Zhang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Jia He
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Rong Huang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Shengjiao Yan
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Jun Lin
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
| | - Yi Jin
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology , Yunnan University , Kunming 650091 , P. R. China
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15
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16
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Ghosh M, Pattanayak S, Dhar BB, Singh KK, Panda C, Sen Gupta S. Selective C-H Bond Oxidation Catalyzed by the Fe-bTAML Complex: Mechanistic Implications. Inorg Chem 2017; 56:10852-10860. [PMID: 28841016 DOI: 10.1021/acs.inorgchem.7b00453] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Nonheme iron complexes bearing tetradentate N-atom-donor ligands with cis labile sites show great promise for chemoselective aliphatic C-H hydroxylation. However, several challenges still limit their widespread application. We report a mechanism-guided development of a peroxidase mimicking iron complex based on the bTAML macrocyclic ligand framework (Fe-bTAML: biuret-modified tetraamido macrocyclic ligand) as a catalyst to perform selective oxidation of unactivated 3° bonds with unprecedented regioselectivity (3°:2° of 110:1 for adamantane oxidation), high stereoretention (99%), and turnover numbers (TONs) up to 300 using mCPBA as the oxidant. Ligand decomposition pathways involving acid-induced demetalation were identified, and this led to the development of more robust and efficient Fe-bTAML complexes that catalyzed chemoselective C-H oxidation. Mechanistic studies, which include correlation of the product formed with the FeV(O) reactive intermediates generated during the reaction, indicate that the major pathway involves the cleavage of C-H bonds by FeV(O). When these oxidations were performed in the presence of air, the yield of the oxidized product doubled, but the stereoretention remained unchanged. On the basis of 18O labeling and other mechanistic studies, we propose a mechanism that involves the dual activation of mCPBA and O2 by Fe-bTAML, leading to formation of the FeV(O) intermediate. This high-valent iron oxo remains the active intermediate for most of the reaction, resulting in high regio- and stereoselectivity during product formation.
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Affiliation(s)
- Munmun Ghosh
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Santanu Pattanayak
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Basab B Dhar
- Department of Chemistry, Shiv Nadar University , Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Kundan K Singh
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Chakadola Panda
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741246, India
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