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Singh G, Duhan N, Dhilip Kumar TJ, Nagaraja CM. Pyrene-Based Nanoporous Covalent Organic Framework for Carboxylation of C-H Bonds with CO 2 and Value-Added 2-Oxazolidinones Synthesis under Ambient Conditions. ACS APPLIED MATERIALS & INTERFACES 2024; 16:5857-5868. [PMID: 38259199 DOI: 10.1021/acsami.3c16690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The selective carbon capture and utilization (CCU) as a one-carbon (C1) feedstock offers dual advantages for mitigating the rising atmospheric CO2 content and producing fine chemicals/fuels. In this context, herein, we report the application of a porous bipyridine-functionalized, pyrene-based covalent organic framework (Pybpy-COF) for the stable anchoring of catalytic Ag(0) nanoparticles (NPs) and its catalytic investigation for fixation of CO2 to commodity chemicals at ambient conditions. Notably, Ag@Pybpy-COF showed excellent catalytic activity for the carboxylation of various terminal alkynes to corresponding alkynyl carboxylic acids/phenylpropiolic acids via C-H bond activation under atmospheric pressure conditions. Besides, carboxylative cyclization of various propargylic amines with CO2 to generate 2-oxazolidinones, an important class of antibiotics, has also been achieved under mild conditions. This significant catalytic activity of Ag@Pybpy-COF with wide functional group tolerance is rendered by the presence of highly exposed, alkynophilic Ag(0) catalytic sites decorated on the pore walls of high surface area (787 m2 g-1) Pybpy-COF. Further, density functional theory calculations unveiled the detailed mechanistic path of the Ag@Pybpy-COF-catalyzed transformation of CO2 to alkynyl carboxylic acids and 2-oxazolidinones. Moreover, the catalyst showed high recyclability for several cycles of reuse without significant loss in its catalytic activity and structural rigidity. This work demonstrates the promising application of Pybpy-COF for stable anchoring of Ag NPs for successful transformation of CO2 to valuable commodity chemicals at ambient conditions.
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Affiliation(s)
- Gulshan Singh
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Nidhi Duhan
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - T J Dhilip Kumar
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - C M Nagaraja
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
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2
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Fabrication of alginate-based multi-crosslinked biomembranes for direct methanol fuel cell application. Carbohydr Polym 2023; 300:120261. [DOI: 10.1016/j.carbpol.2022.120261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022]
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3
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Mitra A, Ghosh S, Paliwal KS, Ghosh S, Tudu G, Chandrasekar A, Mahalingam V. Alumina-Based Bifunctional Catalyst for Efficient CO 2 Fixation into Epoxides at Atmospheric Pressure. Inorg Chem 2022; 61:16356-16369. [PMID: 36194766 DOI: 10.1021/acs.inorgchem.2c02363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The quest toward sustainability and decarbonization demands the development of methods for efficient carbon dioxide capture and utilization. The nonreductive CO2 fixation into epoxides to prepare cyclic carbonates has gained attention in recent years. In this work, we report the development of guanidine hydrochloride-functionalized γ alumina (γ-Al2O3), prepared using green solvents, as an efficient bifunctional catalyst for CO2 fixation. The resulting guanidine-grafted γ-Al2O3 (Al-Gh) proved to be an excellent catalyst to prepare cyclic carbonates from epoxides and CO2 with high selectivity. The nitrogen-rich Al-Gh shows increased CO2 adsorption capacity compared to that of γ-Al2O3. The as-prepared catalyst was able to carry out CO2 fixation at 85 °C under atmospheric pressure in the absence of solvents and external additives (e.g., TBAI or KI). The material showed negligible loss of catalytic activity even after five cycles of catalysis. The catalyst successfully converted many epoxides into their respective cyclic carbonates under the optimized conditions. The gram-scale synthesis of commercially important styrene carbonates from styrene oxide and CO2 using Al-Gh was also achieved. Density functional theory (DFT) calculations revealed the role of alumina in activating the epoxide. This activation facilitated the chloride ion to open the ring to react with CO2. The DFT studies also validated the role of alumina in stabilizing the electron-rich intermediates during the course of the reaction.
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Affiliation(s)
- Antarip Mitra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Sourav Ghosh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Khushboo S Paliwal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Suptish Ghosh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Gouri Tudu
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Aditi Chandrasekar
- School of Arts and Sciences, Azim Premji University, Bangalore 562125, India
| | - Venkataramanan Mahalingam
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
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4
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Rajeshwaree B, Ali A, Mir AQ, Grover J, Lahiri GK, Dutta A, Maiti D. Group 6 transition metal-based molecular complexes for sustainable catalytic CO2 activation. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01378e] [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
CO2 activation is one of the key steps towards CO2 mitigation. In this context, the group 6 transition metal-based molecular catalysts can lead the way.
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Affiliation(s)
- B. Rajeshwaree
- Chemistry Department, IIT Bombay, Powai, Mumbai-400076, India
| | - Afsar Ali
- Chemistry Discipline, IIT Gandhinagar, Palaj, Gandhinagar-382355, India
| | - Ab Qayoom Mir
- Chemistry Discipline, IIT Gandhinagar, Palaj, Gandhinagar-382355, India
| | - Jagrit Grover
- Chemistry Department, IIT Bombay, Powai, Mumbai-400076, India
| | | | - Arnab Dutta
- Chemistry Department, IIT Bombay, Powai, Mumbai-400076, India
- Interdisciplinary Programme in Climate Studies, IIT Bombay, Powai, Mumbai-400076, India
| | - Debabrata Maiti
- Chemistry Department, IIT Bombay, Powai, Mumbai-400076, India
- Interdisciplinary Programme in Climate Studies, IIT Bombay, Powai, Mumbai-400076, India
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5
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Mandal SK, P S, Sarkar P, DUTTA SUPRITI, Das A, Pati SK. Regioselective ring-opening of epoxides towards Markovnikov alcohols: A metal-free catalytic approach using abnormal N-heterocyclic carbene. Chem Commun (Camb) 2022; 58:9540-9543. [DOI: 10.1039/d2cc03549a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report the first metal-free regioselective Markovnikov ring-opening of epoxides (selectivity up to 99%) using an abnormal N-heterocyclic carbene (aNHC) to yield secondary alcohols. DFT calculations and X-ray crystallography...
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6
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Hu C, Paul R, Dai Q, Dai L. Carbon-based metal-free electrocatalysts: from oxygen reduction to multifunctional electrocatalysis. Chem Soc Rev 2021; 50:11785-11843. [PMID: 34559871 DOI: 10.1039/d1cs00219h] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Since the discovery of N-doped carbon nanotubes as the first carbon-based metal-free electrocatalyst (C-MFEC) for oxygen reduction reaction (ORR) in 2009, C-MFECs have shown multifunctional electrocatalytic activities for many reactions beyond ORR, such as oxygen evolution reaction (OER), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CO2RR), nitrogen reduction reaction (NRR), and hydrogen peroxide production reaction (H2O2PR). Consequently, C-MFECs have attracted a great deal of interest for various applications, including metal-air batteries, water splitting devices, regenerative fuel cells, solar cells, fuel and chemical production, water purification, to mention a few. By altering the electronic configuration and/or modulating their spin angular momentum, both heteroatom(s) doping and structural defects (e.g., atomic vacancy, edge) have been demonstrated to create catalytic active sites in the skeleton of graphitic carbon materials. Although certain C-MFECs have been made to be comparable to or even better than their counterparts based on noble metals, transition metals and/or their hybrids, further research and development are necessary in order to translate C-MFECs for practical applications. In this article, we present a timely and comprehensive, but critical, review on recent advancements in the field of C-MFECs within the past five years or so by discussing various types of electrocatalytic reactions catalyzed by C-MFECs. An emphasis is given to potential applications of C-MFECs for energy conversion and storage. The structure-property relationship for and mechanistic understanding of C-MFECs will also be discussed, along with the current challenges and future perspectives.
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Affiliation(s)
- Chuangang Hu
- Australian Carbon Materials Centre (A-CMC), School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Rajib Paul
- Department of Macromolecular Science and Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Quanbin Dai
- Department of Macromolecular Science and Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Liming Dai
- Australian Carbon Materials Centre (A-CMC), School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
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7
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Maji S, Das A, Mandal SK. Mesoionic N-heterocyclic olefin catalysed reductive functionalization of CO 2 for consecutive N-methylation of amines. Chem Sci 2021; 12:12174-12180. [PMID: 34667583 PMCID: PMC8457391 DOI: 10.1039/d1sc02819g] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/02/2021] [Indexed: 11/21/2022] Open
Abstract
A mesoionic N-heterocyclic olefin (mNHO) was introduced as a metal-free catalyst for the reductive functionalization of CO2 leading to consecutive double N-methylation of primary amines in the presence of 9-borabicyclo[3.3.1]nonane (9-BBN). A wide range of secondary amines and primary amines were successfully methylated under mild conditions. The catalyst sustained over six successive cycles of N-methylation of secondary amines without compromising its activity, which encouraged us to check its efficacy towards double N-methylation of primary amines. Moreover, this method was utilized for the synthesis of two commercially available drug molecules. A detailed mechanistic cycle was proposed by performing a series of control reactions along with the successful characterisation of active catalytic intermediates either by single-crystal X-ray study or by NMR spectroscopic studies in association with DFT calculations.
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Affiliation(s)
- Subir Maji
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Arpan Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
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8
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Dong Z, Blaskovits JT, Fadaei-Tirani F, Scopelliti R, Sienkiewicz A, Corminboeuf C, Severin K. Tuning the π-Accepting Properties of Mesoionic Carbenes: A Combined Computational and Experimental Study. Chemistry 2021; 27:11983-11988. [PMID: 34105837 PMCID: PMC8456875 DOI: 10.1002/chem.202101742] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Indexed: 02/02/2023]
Abstract
Mesoionic imidazolylidenes are recognized as excellent electron‐donating ligands in organometallic and main group chemistry. However, these carbene ligands typically show poor π‐accepting properties. A computational analysis of 71 mesoionic imidazolylidenes that bear different aryl or heteroaryl substituents in C2 position was performed. The study has revealed that a diphenyltriazinyl (Dpt) substituent renders the corresponding carbene particularly π‐acidic. The computational results could be corroborated experimentally. A mesoionic imidazolylidene with a Dpt substituent was found to be a better σ‐donor and a better π‐acceptor compared to an Arduengo‐type N‐heterocyclic carbene. To demonstrate the utility of the new carbene, the ligand was used to stabilize a low‐valent paramagnetic tin compound.
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Affiliation(s)
- Zhaowen Dong
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - J Terence Blaskovits
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Farzaneh Fadaei-Tirani
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Andrzej Sienkiewicz
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.,ADSresonances Sarl, Route de Genève 60B, 1028, Préverenges, Switzerland
| | - Clémence Corminboeuf
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Kay Severin
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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9
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Das A, Ahmed J, Rajendran NM, Adhikari D, Mandal SK. A Bottleable Imidazole-Based Radical as a Single Electron Transfer Reagent. J Org Chem 2021; 86:1246-1252. [PMID: 33280378 DOI: 10.1021/acs.joc.0c02465] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Reduction of 1,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-1H-imidazol-3-ium chloride (1) resulted in the formation of the first structurally characterized imidazole-based radical 2. 2 was established as a single electron transfer reagent by treating it with an acceptor molecule tetracyanoethylene. Moreover, radical 2 was utilized as an organic electron donor in a number of organic transformations such as in activation of an aryl-halide bond, alkene hydrosilylation, and in catalytic reduction of CO2 to methoxyborane, all under ambient temperature and pressure.
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Affiliation(s)
- Arpan Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Jasimuddin Ahmed
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - N M Rajendran
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Debashis Adhikari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306, India
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
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10
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P S, Mandal SK. From CO 2 activation to catalytic reduction: a metal-free approach. Chem Sci 2020; 11:10571-10593. [PMID: 34094313 PMCID: PMC8162374 DOI: 10.1039/d0sc03528a] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/19/2020] [Indexed: 12/18/2022] Open
Abstract
Over exploitation of natural resources and human activities are relentlessly fueling the emission of CO2 in the atmosphere. Accordingly, continuous efforts are required to find solutions to address the issue of excessive CO2 emission and its potential effects on climate change. It is imperative that the world looks towards a portfolio of carbon mitigation solutions, rather than a single strategy. In this regard, the use of CO2 as a C1 source is an attractive strategy as CO2 has the potential to be a great asset for the industrial sector and consumers across the globe. In particular, the reduction of CO2 offers an alternative to fossil fuels for various organic industrial feedstocks and fuels. Consequently, efficient and scalable approaches for the reduction of CO2 to products such as methane and methanol can generate value from its emissions. Accordingly, in recent years, metal-free catalysis has emerged as a sustainable approach because of the mild reaction conditions by which CO2 can be reduced to various value-added products. The metal-free catalytic reduction of CO2 offers the development of chemical processes with low cost, earth-abundant, non-toxic reagents, and low carbon-footprint. Thus, this perspective aims to present the developments in both the reduction and reductive functionalization chemistry of CO2 during the last decade using various metal-free catalysts.
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Affiliation(s)
- Sreejyothi P
- Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata Mohanpur-741246 India
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata Mohanpur-741246 India
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11
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Lombardo L, Yang H, Zhao K, Dyson PJ, Züttel A. Solvent- and Catalyst-Free Carbon Dioxide Capture and Reduction to Formate with Borohydride Ionic Liquid. CHEMSUSCHEM 2020; 13:2025-2031. [PMID: 31994287 DOI: 10.1002/cssc.201903514] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/16/2020] [Indexed: 06/10/2023]
Abstract
The metal- and solvent-free capture and reduction of large amounts of CO2 to formate under ambient conditions is achieved by combining a pyrrolidinium-based ionic liquid with a borohydride anion. This material demonstrates one of the highest CO2 capacities at room temperature and 1 bar with up to 1 g CO 2 g-1 IL . CO2 gas reacts with the BH4 - anion to give triformatoborohydride, [HB(OCHO)3 ]- . The reaction occurs without loss in capacity at low CO2 concentration (6 vol % diluted with N2 ). The thermodynamics and kinetics of the reaction were monitored by using a magnetic suspended balance. In addition, more than 1 mol CO 2 mol-1 [ EMPY ] [ BH 4 ] is captured and reduced if air is used as a CO2 source. The product can be then treated with HCl to give formic acid and the corresponding ionic liquid chloride, which can be recycled. This ionic liquid borohydride demonstrates great potential as a CO2 absorber and reducer to produce alternative fuels.
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Affiliation(s)
- Loris Lombardo
- Institute of Chemical Sciences and Engineering, Basic Science Faculty, École polytechnique fédérale de Lausanne, Valais/Wallis, Energypolis, Rue de l'Industrie 17, 1951, Sion, Switzerland
- Empa Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Heena Yang
- Institute of Chemical Sciences and Engineering, Basic Science Faculty, École polytechnique fédérale de Lausanne, Valais/Wallis, Energypolis, Rue de l'Industrie 17, 1951, Sion, Switzerland
- Empa Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Kun Zhao
- Institute of Chemical Sciences and Engineering, Basic Science Faculty, École polytechnique fédérale de Lausanne, Valais/Wallis, Energypolis, Rue de l'Industrie 17, 1951, Sion, Switzerland
- Empa Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Paul J Dyson
- Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Andreas Züttel
- Institute of Chemical Sciences and Engineering, Basic Science Faculty, École polytechnique fédérale de Lausanne, Valais/Wallis, Energypolis, Rue de l'Industrie 17, 1951, Sion, Switzerland
- Empa Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
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12
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Sau SC, Hota PK, Mandal SK, Soleilhavoup M, Bertrand G. Stable abnormal N-heterocyclic carbenes and their applications. Chem Soc Rev 2020; 49:1233-1252. [PMID: 31998907 DOI: 10.1039/c9cs00866g] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Although N-heterocyclic carbenes (NHCs) have been known as ligands for organometallic complexes since the 1960s, these carbenes did not attract considerable attention until Arduengo et al. reported the isolation of a metal-free imidazol-2-ylidene in 1991. In 2001 Crabtree et al. reported a few complexes featuring an NHC isomer, namely an imidazol-5-ylidene, also termed abnormal NHC (aNHCs). In 2009, it was shown that providing to protect the C-2 position of an imidazolium salt, the deprotonation occurred at the C-5 position, affording imidazol-5-ylidenes that could be isolated. Over the last ten years, stable aNHCs have been used for designing a range of catalysts employing Pd(ii), Cu(i), Ni(ii), Fe(0), Zn(ii), Ag(i), and Au(i/iii) metal based precursors. These catalysts were utilized for different organic transformations such as the Suzuki-Miyaura cross-coupling reaction, C-H bond activation, dehydrogenative coupling, Huisgen 1,3-dipolar cycloaddition (click reaction), hydroheteroarylation, hydrosilylation reaction and migratory insertion of carbenes. Main-group metal complexes were also synthesized, including K(i), Al(iii), Zn(ii), Sn(ii), Ge(ii), and Si(ii/iv). Among them, K(i), Al(iii), and Zn(ii) complexes were used for the polymerization of caprolactone and rac-lactide at room temperature. In addition, based on the superior nucleophilicity of aNHCs, relative to that of their nNHCs isomers, they were used for small molecules activation, such as carbon dioxide (CO2), nitrous oxide (N2O), tetrahydrofuran (THF), tetrahydrothiophene and 9-borabicyclo[3.3.1]nonane (9BBN). aNHCs have also been shown to be efficient metal-free catalysts for ring opening polymerization of different cyclic esters at room temperature; they are among the most active metal-free catalysts for ε-caprolactone polymerization. Recently, aNHCs successfully accomplished the metal-free catalytic formylation of amides using CO2 and the catalytic reduction of carbon dioxide, including atmospheric CO2, into methanol, under ambient conditions. Although other transition metal complexes featuring aNHCs as ligand have been prepared and used in catalysis, this review article summarize the results obtained with the isolated aNHCs.
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Affiliation(s)
- Samaresh Chandra Sau
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, Nadia, West Bengal, India.
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Hota PK, Maji S, Ahmed J, Rajendran NM, Mandal SK. NHC-catalyzed silylative dehydration of primary amides to nitriles at room temperature. Chem Commun (Camb) 2020; 56:575-578. [PMID: 31830152 DOI: 10.1039/c9cc08413d] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report an abnormal N-heterocyclic carbene catalyzed dehydration of primary amides in the presence of a silane. This process bypasses the energy demanding 1,2-siloxane elimination step usually required for metal/silane catalyzed reactions. A detailed mechanistic cycle of this process has been proposed based on experimental evidence along with computational study.
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Affiliation(s)
- Pradip Kumar Hota
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
| | - Subir Maji
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
| | - Jasimuddin Ahmed
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
| | - N M Rajendran
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
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14
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Sokolovicz YCA, Nieto Faza O, Specklin D, Jacques B, López CS, dos Santos JHZ, Schrekker HS, Dagorne S. Acetate-catalyzed hydroboration of CO2 for the selective formation of methanol-equivalent products. Catal Sci Technol 2020. [DOI: 10.1039/d0cy00118j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The acetate anion is a highly robust and effective catalyst for the selective hydroboration of CO2 to methanol-equivalent products.
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Affiliation(s)
| | - Olalla Nieto Faza
- Epto. Química Orgánica
- Universidade de Vigo
- Facultade de Ciencias
- Ourense
- Spain
| | - David Specklin
- Institute of Chemistry
- Université de Strasbourg
- CNRS
- Strasbourg
- France
| | - Béatrice Jacques
- Institute of Chemistry
- Université de Strasbourg
- CNRS
- Strasbourg
- France
| | - Carlos Silva López
- Epto. Química Orgánica
- Universidade de Vigo
- Facultade de Ciencias
- Ourense
- Spain
| | | | - Henri S. Schrekker
- Institute of Chemistry
- Universidade Federal do Rio Grande do Sul
- Porto Alegre
- Brazil
| | - Samuel Dagorne
- Institute of Chemistry
- Université de Strasbourg
- CNRS
- Strasbourg
- France
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15
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Bhunia M, Sahoo SR, Das A, Ahmed J, P S, Mandal SK. Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: integrating nucleophilicity with Lewis acidic activation. Chem Sci 2019; 11:1848-1854. [PMID: 34123278 PMCID: PMC8148392 DOI: 10.1039/c9sc05953a] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis of pharmaceutically valuable precursors on a gram scale. During mechanistic investigation, several intermediates were isolated and characterized through spectroscopic techniques and one of the catalytic intermediates was characterized through single-crystal XRD. A well-defined catalyst and isolable intermediate along with several stoichiometric experiments, in situ NMR experiments and the DFT study helped us to sketch the mechanistic pathway for this reduction process unravelling the dual role of the catalyst involving nucleophilic activation by aNHC along with Lewis acidic activation by K ions. An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions.![]()
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Affiliation(s)
- Mrinal Bhunia
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Sumeet Ranjan Sahoo
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Arpan Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Jasimuddin Ahmed
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Sreejyothi P
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur-741246 India
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Manar KK, Porwal VK, Kamte RS, Adhikari M, Thakur SK, Bawari D, Choudhury AR, Singh S. Reactions of a BICAAC with hydroboranes: propensity for Lewis adduct formation and carbene insertion into the B-H bond. Dalton Trans 2019; 48:17472-17478. [PMID: 31714564 DOI: 10.1039/c9dt03382c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of a bicyclic (alkyl)(amino)carbene (BICAAC) towards different boranes has been examined in the present work. The reactions with boranes BX3·SMe2 (X = H, Cl, Br), BF3·OEt2 and BCl3 yield Lewis adducts [BICAAC·BH3] (1), [BICAAC·BHCl2] (2), [BICAAC·BH2Cl] (3), [BICAAC·BF3] (4), [BICAAC·BCl3] (5) and [BICAAC·BBr3] (6) respectively, whereas more hydridic boranes, 9-borabicyclo[3.3.1]nonane (9-BBN) and catecholborane (HBcat), enable the insertion of the carbene carbon into the B-H bond to form [BICAAC(H)-(9-BBN)] (7) and [BICAAC(H)-Bcat] (8). These complexes are the first examples of BICAAC-boron compounds and have been characterized using IR, multinuclear NMR spectroscopy, HRMS spectrometry and single crystal X-ray diffraction. Computational analyses were also performed to gain insight into the mechanism of B-H bond activation and adduct formation. Furthermore, the reactions of the BICAAC with boranes have been compared with the known reactions of CAACs and NHCs.
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Affiliation(s)
- Krishna K Manar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Mohali 140306, Punjab, India.
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