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Ibáñez-Ibáñez L, Mollar-Cuni A, Apaloo-Messan E, Sharma AK, Mata JA, Maseras F, Vicent C. Ion mobility mass spectrometry uncovers regioselectivity in the carboxylate-assisted C-H activation of palladium N-heterocyclic carbene complexes. Dalton Trans 2024; 53:656-665. [PMID: 38073605 DOI: 10.1039/d3dt02793g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Carboxylate-assisted Pd-catalyzed C-H bond activation constitutes a mild and versatile synthetic tool to efficiently and selectively cleave inert C-H bonds. Herein, we demonstrate a simple method to experimentally evaluate both reactivity and selectivity in such systems using mass spectrometry (MS) methods. The N-heterocyclic carbene (NHC) cations [(NHC)PdX]+, bearing as X- ligand bases commonly used to promote the C-H activation (carboxylates and bicarbonate), are generated in the gas-phase by ESI-MS. Their C-H bond activation at the N-bound groups of the NHC is then studied using Collision Induced Dissociation (CID) experiments. Ion Mobility Spectrometry (IM)-MS is exploited to identify a number of regioisomers associated with the distinctive site selective C-H activations. It is demonstrated that such C-H activation concomitant with acetic acid release occurs from a mixture of activated [(NHC-H)Pd(CH3CO2H)]+ and non-activated [(NHC)Pd(CH3CO2)]+ complexes. The identity of the X-type ligands (X = Cl-, carboxylates and bicarbonate) has a significant impact on the regioisomer branching ratio upon CID conditions. IM-MS in conjunction with a DFT mechanistic study is presented for the acetate-assisted C-H activation of the [(NHC)Pd(CH3CO2)]+ cation featuring butyl and aryl as N-donor groups.
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Affiliation(s)
- Laura Ibáñez-Ibáñez
- Institute of Advanced Materials (INAM), Net of organometallic chemistry for sustainable solutions (OASIS), Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain.
| | - Andres Mollar-Cuni
- Institute of Advanced Materials (INAM), Net of organometallic chemistry for sustainable solutions (OASIS), Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain.
| | - Edmond Apaloo-Messan
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), The Barcelona Institute of Science and Technology, Avgda. Països Catalans, 16, 43007 Tarragona, Spain.
| | - Akhilesh K Sharma
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), The Barcelona Institute of Science and Technology, Avgda. Països Catalans, 16, 43007 Tarragona, Spain.
| | - Jose A Mata
- Institute of Advanced Materials (INAM), Net of organometallic chemistry for sustainable solutions (OASIS), Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain.
| | - Feliu Maseras
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), The Barcelona Institute of Science and Technology, Avgda. Països Catalans, 16, 43007 Tarragona, Spain.
| | - Cristian Vicent
- Serveis Centrals d'Instrumentació Científica (SCIC). Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain.
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Böhme M, Termühlen S, Dutschke PD, Hepp A, Hahn FE. Formation of C NHC∧C alkyl and C NHC∧C aryl κ 2-Chelate Complexes through Competitive sp 3- and sp 2-CH Activations: An Experimental and Computational Study. ACS OMEGA 2023; 8:48515-48521. [PMID: 38144098 PMCID: PMC10733921 DOI: 10.1021/acsomega.3c08427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/10/2023] [Indexed: 12/26/2023]
Abstract
Depending on the chelate ring present, cyclometalated complexes are useful catalysts for various reactions. The reactivity of IrIII and RhIII NHC complexes bearing aliphatic or aromatic N,N'-substituents and thus featuring various metalation sites toward cyclometalation has been investigated. The RhIII complex bearing an N-mesityl-N'-benzyl-NHC does not participate in any cyclometalation, while the IrIII complex reacts under metalation of an ortho-methyl group of the Mes substituent to give complex [3] with a six-membered chelate ring. The RhIII and IrIII complexes bearing an N-o-tolyl,N-benzyl-NHC undergo sp2-CH activation to yield the cyclometalated complexes [4] and [5] featuring a five-membered CNHC∧C chelate ring. Density functional theory (DFT) studies corroborated the experimental findings.
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Affiliation(s)
- Matthias
D. Böhme
- Institut für Anorganische
und Analytische Chemie, Westfälische
Wilhelms-Universität Münster, Corrensstraße 28-30, 48149 Münster, Germany
| | - Sebastian Termühlen
- Institut für Anorganische
und Analytische Chemie, Westfälische
Wilhelms-Universität Münster, Corrensstraße 28-30, 48149 Münster, Germany
| | - Patrick D. Dutschke
- Institut für Anorganische
und Analytische Chemie, Westfälische
Wilhelms-Universität Münster, Corrensstraße 28-30, 48149 Münster, Germany
| | - Alexander Hepp
- Institut für Anorganische
und Analytische Chemie, Westfälische
Wilhelms-Universität Münster, Corrensstraße 28-30, 48149 Münster, Germany
| | - F. Ekkehardt Hahn
- Institut für Anorganische
und Analytische Chemie, Westfälische
Wilhelms-Universität Münster, Corrensstraße 28-30, 48149 Münster, Germany
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3
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Mollar-Cuni A, Ibáñez-Ibáñez L, Guisado-Barrios G, Mata JA, Vicent C. Introducing Ion Mobility Mass Spectrometry to Identify Site-Selective C-H Bond Activation in N-Heterocyclic Carbene Metal Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:2291-2300. [PMID: 36374280 DOI: 10.1021/jasms.2c00257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The activation of C-H bonds in a selective manner still constitutes a major challenge from a synthetic point of view; thus, it remains an active area of fundamental and applied research. Herein, we introduce ion mobility spectrometry mass spectrometry-based (IM-MS) approaches to uncover site-selective C-H bond activation in a series of metal complexes of general formula [(NHC)LMCl]+ (NHC = N-heterocyclic carbene; L = pentamethylcyclopentadiene (Cp*) or p-cymene; M = Pd, Ru, and Ir). The C-H bond activation at the N-bound groups of the NHC ligand is promoted upon collision induced dissociation (CID). The identification of the resulting [(NHC-H)LM]+ isomers relies on the distinctive topology that such cyclometalated isomers adopt upon site-selective C-H bond activation. Such topological differences can be reliably evidenced as different mobility peaks in their respective CID-IM mass spectra. Alternative isomers are also identified via dehydrogenation at the Cp*/p-cymene (L) ligands to afford [(NHC)(L-H)M]+. The fragmentation of the ion mobility-resolved peaks is also investigated by CID-IM-CID. It enables the assignment of mobility peaks to the specific isomers formed from C(sp2)-H or C(sp3)-H bond activation and distinguishes them from the Cp*/p-cymene (L) dehydrogenation isomers. The conformational change of the NHC ligands upon C-H bond activation, concomitant with cyclometalation, is also discussed on the basis of the estimated collision cross section (CCS). A unique conformation change of the pyrene-tagged NHC members is identified that involves the reorientation of the NHC ring accompanied by a folding of the pyrene moiety.
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Affiliation(s)
- Andrés Mollar-Cuni
- Institute of Advanced Materials (INAM), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain
| | - Laura Ibáñez-Ibáñez
- Institute of Advanced Materials (INAM), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain
| | - Gregorio Guisado-Barrios
- Departamento de Química Inorgánica. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, 50009Zaragoza, Spain
| | - Jose A Mata
- Institute of Advanced Materials (INAM), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain
| | - Cristian Vicent
- Serveis Centrals d'Intrumentació Científica (SCIC). Universitat Jaume I, Avda. Sos Baynat s/n, 12071Castellón, Spain
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4
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Ganguli K, Belkova N, Kundu S. Cyclometalated (NNC)Ru(II) complex catalyzed β-methylation of alcohols using methanol. Dalton Trans 2022; 51:4354-4365. [DOI: 10.1039/d1dt03967a] [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
Indolyl fragment containing phenanthroline based new ligands and their corresponding Ru(II) complexes were synthesized and fully characterized by various spectroscopic techniques. Catalytic activity of these newly synthesized cyclometalated (NNC)Ru(II) complexes...
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5
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Neshat A, Mastrorilli P, Mousavizadeh Mobarakeh A. Recent Advances in Catalysis Involving Bidentate N-Heterocyclic Carbene Ligands. Molecules 2021; 27:95. [PMID: 35011327 PMCID: PMC8746573 DOI: 10.3390/molecules27010095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/02/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
Since the discovery of persistent carbenes by the isolation of 1,3-di-l-adamantylimidazol-2-ylidene by Arduengo and coworkers, we witnessed a fast growth in the design and applications of this class of ligands and their metal complexes. Modular synthesis and ease of electronic and steric adjustability made this class of sigma donors highly popular among chemists. While the nature of the metal-carbon bond in transition metal complexes bearing N-heterocyclic carbenes (NHCs) is predominantly considered to be neutral sigma or dative bonds, the strength of the bond is highly dependent on the energy match between the highest occupied molecular orbital (HOMO) of the NHC ligand and that of the metal ion. Because of their versatility, the coordination chemistry of NHC ligands with was explored with almost all transition metal ions. Other than the transition metals, NHCs are also capable of establishing a chemical bond with the main group elements. The advances in the catalytic applications of the NHC ligands linked with a second tether are discussed. For clarity, more frequently targeted catalytic reactions are considered first. Carbon-carbon coupling reactions, transfer hydrogenation of alkenes and carbonyl compounds, ketone hydrosilylation, and chiral catalysis are among highly popular reactions. Areas where the efficacy of the NHC based catalytic systems were explored to a lesser extent include CO2 reduction, C-H borylation, alkyl amination, and hydroamination reactions. Furthermore, the synthesis and applications of transition metal complexes are covered.
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Affiliation(s)
- Abdollah Neshat
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran;
| | - Piero Mastrorilli
- Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, Via Orabona, I-70125 Bari, Italy;
| | - Ali Mousavizadeh Mobarakeh
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran;
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6
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Tiwari CS, Illam PM, Donthireddy SNR, Rit A. Recent Advances in the Syntheses and Catalytic Applications of Homonuclear Ru-, Rh-, and Ir-Complexes of C NHC ^C Cyclometalated Ligands. Chemistry 2021; 27:16581-16600. [PMID: 34469015 DOI: 10.1002/chem.202102540] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Indexed: 12/17/2022]
Abstract
In the past few decades, chemistry of cyclometalated species has gained momentum with increased applications in several areas of scientific developments. Cyclometalation reactions result in the formation of stable metallacycles through the generation of metal-carbon covalent bonds by activating the unreactive Csp2 -H or Csp3 -H bonds. The extra stability gained by the formation of metallacycles enhances their applicability scopes especially in the area of homogeneous catalysis. In the recent research development in this area, NHC ligands (strong σ-donor and generally, weak π-acceptor) have been found to be one of the most suitable candidates for the intramolecular C-H activation process which leads to the cyclometalated species. The growth in the area of cyclometalation chemistry that started in the late 20th century is still continuing and in the past few decades, various examples of NHC derived transition metal-based cyclometalated complexes came into the picture. As covering all the reported literatures in this area (includes mainly late transition metals) will exceed the limits of minireview, we restricted ourselves to the recent (2015 - May 2021) examples of the most common Ru-, Rh-, and Ir-based CNHC ^C cyclometalated complexes and their applications in various homogeneous catalytic conversions such as transfer hydrogenation, amidation, oxidation of alcohols, annulations, and so forth.
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Affiliation(s)
| | | | - S N R Donthireddy
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Arnab Rit
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
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7
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Ruthenacycles and Iridacycles as Transfer Hydrogenation Catalysts. Molecules 2021; 26:molecules26134076. [PMID: 34279416 PMCID: PMC8271416 DOI: 10.3390/molecules26134076] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 11/29/2022] Open
Abstract
In this review, we describe the synthesis and use in hydrogen transfer reactions of ruthenacycles and iridacycles. The review limits itself to metallacycles where a ligand is bound in bidentate fashion to either ruthenium or iridium via a carbon–metal sigma bond, as well as a dative bond from a heteroatom or an N-heterocyclic carbene. Pincer complexes fall outside the scope. Described are applications in (asymmetric) transfer hydrogenation of aldehydes, ketones, and imines, as well as reductive aminations. Oxidation reactions, i.e., classical Oppenauer oxidation, which is the reverse of transfer hydrogenation, as well as dehydrogenations and oxidations with oxygen, are described. Racemizations of alcohols and secondary amines are also catalyzed by ruthenacycles and iridacycles.
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8
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Botubol-Ares JM, Cordón-Ouahhabi S, Moutaoukil Z, Collado IG, Jiménez-Tenorio M, Puerta MC, Valerga P. Methylene-Linked Bis-NHC Half-Sandwich Ruthenium Complexes: Binding of Small Molecules and Catalysis toward Ketone Transfer Hydrogenation. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00045] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- José Manuel Botubol-Ares
- Departamento de Química Orgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - Safa Cordón-Ouahhabi
- Departamento de Química Orgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - Zakaria Moutaoukil
- Departamento de Química Orgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - Isidro G. Collado
- Departamento de Química Orgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - Manuel Jiménez-Tenorio
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - M. Carmen Puerta
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - Pedro Valerga
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica-INBIO, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
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9
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Piehl P, Amuso R, Spannenberg A, Gabriele B, Neumann H, Beller M. Efficient methylation of anilines with methanol catalysed by cyclometalated ruthenium complexes. Catal Sci Technol 2021. [DOI: 10.1039/d0cy02210a] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cyclometalated ruthenium allow the effective and selective N-methylation of anilines under mild conditions.
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Affiliation(s)
- Patrick Piehl
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
| | - Roberta Amuso
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
- Laboratory of Industrial and Synthetic Organic Chemistry (LISOC)
- Department of Chemistry and Chemical Technologies
| | | | - Bartolo Gabriele
- Laboratory of Industrial and Synthetic Organic Chemistry (LISOC)
- Department of Chemistry and Chemical Technologies
- University of Calabria
- 87036 Arcavacata di Rende
- Italy
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10
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11
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Piehl P, Amuso R, Alberico E, Junge H, Gabriele B, Neumann H, Beller M. Cyclometalated Ruthenium Pincer Complexes as Catalysts for the α-Alkylation of Ketones with Alcohols. Chemistry 2020; 26:6050-6055. [PMID: 31985105 PMCID: PMC7317879 DOI: 10.1002/chem.202000396] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Indexed: 11/29/2022]
Abstract
Ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N‐bound ligands have been prepared and fully characterized for the first time. By replacing CO and H− as ancillary ligands in such complexes, additional electronic and steric modifications of this topical class of catalysts are possible. The advantages of the new catalysts are demonstrated in the general α‐alkylation of ketones with alcohols following a hydrogen autotransfer protocol. Herein, various aliphatic and benzylic alcohols were applied as green alkylating agents for ketones bearing aromatic, heteroaromatic or aliphatic substituents as well as cyclic ones. Mechanistic investigations revealed that during catalysis, Ru carboxylate complexes are predominantly formed whereas neither the PNP nor the CN ligand are released from the catalyst in significant amounts.
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Affiliation(s)
- Patrick Piehl
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059, Rostock, Germany
| | - Roberta Amuso
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059, Rostock, Germany.,Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria, Via Pietro Bucci 12/C, 87036, Arcavacata di, Rende (CS, Italy
| | - Elisabetta Alberico
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059, Rostock, Germany.,Istituto di Chimica Biomolecolare, CNR, tr. La Crucca 3, 07100, Sassari, Italy
| | - Henrik Junge
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059, Rostock, Germany
| | - Bartolo Gabriele
- Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria, Via Pietro Bucci 12/C, 87036, Arcavacata di, Rende (CS, Italy
| | - Helfried Neumann
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059, Rostock, Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059, Rostock, Germany
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12
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Ruthenium(II) complexes bearing N-heterocyclic carbene ligands with wingtip groups and their catalytic activity in the transfer hydrogenation of ketones. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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13
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Qiao X, Qiu D, Lin N, Zhu J, Deng W, Yao Z. Half‐sandwich ruthenium‐based versatile catalyst for both alcohol oxidation and catalytic hydrogenation of carbonyl compounds in aqueous media. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.4875] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Xin‐Chao Qiao
- School of Chemical and Environmental EngineeringShanghai Institute of Technology Shanghai 201418 China
| | - Dan‐Chen Qiu
- School of Chemical and Environmental EngineeringShanghai Institute of Technology Shanghai 201418 China
| | - Nan Lin
- School of Chemical and Environmental EngineeringShanghai Institute of Technology Shanghai 201418 China
| | - Jing‐Wei Zhu
- School of Chemical and Environmental EngineeringShanghai Institute of Technology Shanghai 201418 China
| | - Wei Deng
- School of Chemical and Environmental EngineeringShanghai Institute of Technology Shanghai 201418 China
| | - Zi‐Jian Yao
- School of Chemical and Environmental EngineeringShanghai Institute of Technology Shanghai 201418 China
- Key Laboratory of Synthetic and Self‐Assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic ChemistryChinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- State Key Laboratory of Coordination ChemistryNanjing University Nanjing 210023 China
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14
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Balamurugan G, Balaji S, Ramesh R, Bhuvanesh NS. Synthesis and Structures of Arene Ruthenium (II)-NHC Complexes: Efficient Catalytic α-alkylation of ketones via Hydrogen Auto Transfer Reaction. Appl Organomet Chem 2018. [DOI: 10.1002/aoc.4696] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Gunasekaran Balamurugan
- Centre for organometallic Chemistry, School of Chemistry; Bharathidasan University; Tiruchirapalli 620024 Tamilnadu India
| | - Sundarraman Balaji
- Centre for organometallic Chemistry, School of Chemistry; Bharathidasan University; Tiruchirapalli 620024 Tamilnadu India
| | - Rengan Ramesh
- Centre for organometallic Chemistry, School of Chemistry; Bharathidasan University; Tiruchirapalli 620024 Tamilnadu India
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15
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Bauri S, Donthireddy SNR, Illam PM, Rit A. Effect of Ancillary Ligand in Cyclometalated Ru(II)-NHC-Catalyzed Transfer Hydrogenation of Unsaturated Compounds. Inorg Chem 2018; 57:14582-14593. [PMID: 30421610 DOI: 10.1021/acs.inorgchem.8b02246] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In an effort to develop efficient Ru(II)-NHC-based catalyst considering their stereoelectronic effect for hydride-transfer reaction, we found that the ancillary NHC ligand can play a significant role in its catalytic performance. This effect is demonstrated by comparing the activity of two different types of orthometalated precatalysts of general formula [( p-cymene)(NHC)RuII(X)] (NHC = an imidazolylidene-based ImNHC, compound 2a-c, or a mesoionic triazolylidene-based tzNHC, compound 4) in transfer hydrogenation of carbonyl substrates. The electron-rich precatalyst, 2c, containing p-OMe-substituted NHC ligand performed significantly better than both unsubstituted complex 2a and p-CF3 substituted electron-poor complex 2b in ketone reduction. Whereas bulky mesoionic triazolylidene ligand containing complex 4 was found to be superior catalyst for aldehyde reduction and the precatalyst 2a is more suitable for the selective transfer hydrogenation of a wide range of aromatic aldimines to amines. To the best of our knowledge, this is the first systematic study on the effect of stereoelectronic tuning of ancillary orthometalated NHC ligand in Ru(II)-catalyzed transfer hydrogenations of various types of unsaturated compounds with broad substrate scope.
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Affiliation(s)
- Somnath Bauri
- Department of Chemistry , Indian Institute of Technology Madras , Chennai 600036 , India
| | - S N R Donthireddy
- Department of Chemistry , Indian Institute of Technology Madras , Chennai 600036 , India
| | | | - Arnab Rit
- Department of Chemistry , Indian Institute of Technology Madras , Chennai 600036 , India
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16
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Thirumal M, Ramesh M, Kaleeswaran D, Venkatachalam GS. Synthesis, Structure and Catalytic Oxidation of Ruthenium(III) Complexes Containing 1‐(Arylazo)naphthol Ligands Derived from
β
−Naphthol and Sterically Bulky Amines. ChemistrySelect 2018. [DOI: 10.1002/slct.201802340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Muniyappan Thirumal
- PG & Research Department of ChemistryGovernment Arts College, Dharmapuri- 636 705 Tamilnadu India
| | - Madhan Ramesh
- PG & Research Department of ChemistryGovernment Arts College, Dharmapuri- 636 705 Tamilnadu India
| | - Dhananjayan Kaleeswaran
- Department of ChemistryIndian Institute of Technology Bombay, Powai, Mumbai- 400 076 Maharashtra India
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17
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Hey DA, Reich RM, Baratta W, Kühn FE. Current advances on ruthenium(II) N-heterocyclic carbenes in hydrogenation reactions. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.06.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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