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Kumar S, Patra DK, Rit A. Heterobimetallic Complexes Bridged by an Unsymmetrical Bis(NHC) Ligand: Study of Enhanced Catalytic Activity in Tandem Transformations and Understanding of Cooperativity between the Metal Centers. Chemistry 2023; 29:e202302180. [PMID: 37702918 DOI: 10.1002/chem.202302180] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/12/2023] [Accepted: 09/12/2023] [Indexed: 09/14/2023]
Abstract
The bis(azolium) salt [L1-H2 ]Br2 was found to serve as a suitable platform for accessing the heterobimetallic IrIII -M (M=PdII /AuI ) and PdII -IrIII complexes. Initially, selective mono-metalation of [L1-H2 ]Br2 yielded an orthometalated IrIII - or non-orthometalated PdII -complex. Sequential metalation of the mono-IrIII complex resulted in the formation of heterobimetallic IrIII -PdII /AuI complexes. Similarly, a distinct heterobimetallic PdII -IrIII complex was synthesized starting from the mono-PdII complex. Further, the corresponding homobimetallic IrIII -IrIII and PdII -PdII complexes were directly obtained from [L1-H2 ]Br2 . Additionally, monometallic PdII and IrIII analogues were synthesized from [L2-H]Br and [L3-H]Br, respectively. The heterobimetallic IrIII -PdII and PdII -IrIII complexes were then evaluated as catalysts in various one-pot tandem catalytic reactions in which they demonstrated superior activity than the mixtures of both their corresponding homobimetallic IrIII -IrIII /PdII -PdII and monometallic IrIII /PdII counterparts, under the constant concentrations of metal centers. Moreover, while comparing complexes IrIII -PdII and PdII -IrIII , the former exhibits higher activity in all the studied reactions. All these findings suggest the presence of some form of cooperativity between the two metal centers (Ir and Pd) connected by a single ligand framework in IrIII -PdII and PdII -IrIII complex, with IrIII -PdII displaying better cooperativity that has been validated by electrochemical, NMR, and DFT studies.
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Affiliation(s)
- Shashi Kumar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Deeptesh K Patra
- 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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Poyatos M, Peris E. Insights into the past and future of Janus-di-N-heterocyclic carbenes. Dalton Trans 2021; 50:12748-12763. [PMID: 34581341 DOI: 10.1039/d1dt02035h] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Janus di-N-heterocyclic carbene (NHC) ligands are a subclass of poly-NHCs that feature coordination to two transition metals in a facially opposed manner. The combination of the structural features of Janus type ligands, with the properties conferred by the NHC ligands, has conferred Janus-di-NHCs with privileged attributes for their use in diverse areas of research, such as homogeneous catalysis, materials chemistry and supramolecular chemistry. In molecular chemistry, Janus di-NHCs constitute one of the most useful chemical platforms for constructing dimetallic structures, and this includes both homo- and hetero-dimetallic compounds. This review aims to cover the most relevant advances in the use of Janus-di-NHCs during the last 15 years, by classifying them according to their specific structural features.
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Affiliation(s)
- Macarena Poyatos
- Institute of Advanced Materials (INAM), Universitat Jaume I, Av. Vicente Sos Baynat s/n, Castellón, E-1271, Spain.
| | - Eduardo Peris
- Institute of Advanced Materials (INAM), Universitat Jaume I, Av. Vicente Sos Baynat s/n, Castellón, E-1271, Spain.
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Ruiz‐Zambrana C, Gutiérrez‐Blanco A, Gonell S, Poyatos M, Peris E. Redox‐Switchable Cycloisomerization of Alkynoic Acids with Napthalenediimide‐Derived N‐Heterocyclic Carbene Complexes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- César Ruiz‐Zambrana
- Institute of Advanced Materials (INAM). Universitat Jaume I. Av. Vicente Sos Baynat s/n. 12071 Castellón Spain
| | - Ana Gutiérrez‐Blanco
- Institute of Advanced Materials (INAM). Universitat Jaume I. Av. Vicente Sos Baynat s/n. 12071 Castellón Spain
| | - Sergio Gonell
- Institute of Advanced Materials (INAM). Universitat Jaume I. Av. Vicente Sos Baynat s/n. 12071 Castellón Spain
| | - Macarena Poyatos
- Institute of Advanced Materials (INAM). Universitat Jaume I. Av. Vicente Sos Baynat s/n. 12071 Castellón Spain
| | - Eduardo Peris
- Institute of Advanced Materials (INAM). Universitat Jaume I. Av. Vicente Sos Baynat s/n. 12071 Castellón Spain
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Ruiz-Zambrana C, Gutiérrez-Blanco A, Gonell S, Poyatos M, Peris E. Redox-Switchable Cycloisomerization of Alkynoic Acids with Napthalenediimide-Derived N-Heterocyclic Carbene Complexes. Angew Chem Int Ed Engl 2021; 60:20003-20011. [PMID: 34255909 PMCID: PMC8457061 DOI: 10.1002/anie.202107973] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Indexed: 12/22/2022]
Abstract
Two naphthalene‐diimide (NDI) bis‐imidazolium salts have been used as N‐heterocyclic carbene (NHC) precursors for the preparation of NDI‐functionalized complexes of rhodium and iridium of general formula [MCl(NDI‐NHC)(COD)] (M=Rh, Ir; NDI‐NHC=NDI‐functionalized NHC ligand). Comparison of the IR spectra of the complexes [IrCl(NDI‐NHC)(CO)2] and their related one‐ and two‐electron reduced forms, reveal that each one‐electron reduction produces a decrease of the average ν(CO) of 9–10 cm−1, indicating a significant enhancement of the electron‐richness of the metal. The [MCl(NDI‐NHC)(COD)] complexes were tested in the catalytic cycloisomerization of alkynoic acids. The one‐electron reduced forms showed greatly enhanced activities. For the cyclization of 5‐hexynoic acid, the two‐electron reduction of the ligand produced further enhancement of the catalytic activity, therefore showing that the catalyst can switch between three redox species with three distinct catalytic activities.
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Affiliation(s)
- César Ruiz-Zambrana
- Institute of Advanced Materials (INAM)., Universitat Jaume I., Av. Vicente Sos Baynat s/n., 12071, Castellón, Spain
| | - Ana Gutiérrez-Blanco
- Institute of Advanced Materials (INAM)., Universitat Jaume I., Av. Vicente Sos Baynat s/n., 12071, Castellón, Spain
| | - Sergio Gonell
- Institute of Advanced Materials (INAM)., Universitat Jaume I., Av. Vicente Sos Baynat s/n., 12071, Castellón, Spain
| | - Macarena Poyatos
- Institute of Advanced Materials (INAM)., Universitat Jaume I., Av. Vicente Sos Baynat s/n., 12071, Castellón, Spain
| | - Eduardo Peris
- Institute of Advanced Materials (INAM)., Universitat Jaume I., Av. Vicente Sos Baynat s/n., 12071, Castellón, Spain
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Chen C, Liu FS, Szostak M. BIAN-NHC Ligands in Transition-Metal-Catalysis: A Perfect Union of Sterically Encumbered, Electronically Tunable N-Heterocyclic Carbenes? Chemistry 2021; 27:4478-4499. [PMID: 32989914 PMCID: PMC7940599 DOI: 10.1002/chem.202003923] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/24/2020] [Indexed: 12/12/2022]
Abstract
The discovery of NHCs (NHC = N-heterocyclic carbenes) as ancillary ligands in transition-metal-catalysis ranks as one of the most important developments in synthesis and catalysis. It is now well-recognized that the strong σ-donating properties of NHCs along with the ease of scaffold modification and a steric shielding of the N-wingtip substituents around the metal center enable dramatic improvements in catalytic processes, including the discovery of reactions that are not possible using other ancillary ligands. In this context, although the classical NHCs based on imidazolylidene and imidazolinylidene ring systems are now well-established, recently tremendous progress has been made in the development and catalytic applications of BIAN-NHC (BIAN = bis(imino)acenaphthene) class of ligands. The enhanced reactivity of BIAN-NHCs is a direct result of the combination of electronic and steric properties that collectively allow for a major expansion of the scope of catalytic processes that can be accomplished using NHCs. BIAN-NHC ligands take advantage of (1) the stronger σ-donation, (2) lower lying LUMO orbitals, (3) the presence of an extended π-system, (4) the rigid backbone that pushes the N-wingtip substituents closer to the metal center by buttressing effect, thus resulting in a significantly improved control of the catalytic center and enhanced air-stability of BIAN-NHC-metal complexes at low oxidation state. Acenaphthoquinone as a precursor enables facile scaffold modification, including for the first time the high yielding synthesis of unsymmetrical NHCs with unique catalytic properties. Overall, this results in a highly attractive, easily accessible class of ligands that bring major advances and emerge as a leading practical alternative to classical NHCs in various aspects of catalysis, cross-coupling and C-H activation endeavors.
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Affiliation(s)
- Changpeng Chen
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ, 07102, USA
| | - Feng-Shou Liu
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ, 07102, USA
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan, Guangdong, 528458, China
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ, 07102, USA
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Olgun Karataş M, Alıcı B. Comparison of the catalytic performances of bridged bi-metallic and non-bridged mono-metallic PEPPSI type palladium N-heterocyclic carbene complexes. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2020.107890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Naz NR, Schnakenburg G, Mikeházi A, Kelemen Z, Nyulászi L, Boeré RT, Streubel R. Janus bis(NHCs) tuned by heteroatom-bridge oxidation states. Chem Commun (Camb) 2020; 56:2646-2649. [PMID: 32022028 DOI: 10.1039/c9cc08468a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Synthesis of the first tricyclic bis(carbenes) with facially opposed imidazole-2-ylidenes and two linking phosphorus centres in different oxidation states is presented using a modular, high-yield synthetic route. The formation of homo bimetallic coinage metal complexes provides a glimpse on their potential use.
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Affiliation(s)
- Nabila Rauf Naz
- Institut für Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
| | - Gregor Schnakenburg
- Institut für Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
| | - Antal Mikeházi
- Department of Inorganic and Analytical Chemistry and MTA-BME Computation Driven Chemistry Research Group, Budapest University of Technology and Economics, Szt Gellert ter 4, 1111 Budapest, Hungary.
| | - Zsolt Kelemen
- Department of Inorganic and Analytical Chemistry and MTA-BME Computation Driven Chemistry Research Group, Budapest University of Technology and Economics, Szt Gellert ter 4, 1111 Budapest, Hungary.
| | - László Nyulászi
- Department of Inorganic and Analytical Chemistry and MTA-BME Computation Driven Chemistry Research Group, Budapest University of Technology and Economics, Szt Gellert ter 4, 1111 Budapest, Hungary.
| | - René T Boeré
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, AB T1K3M4, Canada.
| | - Rainer Streubel
- Institut für Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
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