1
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Hendi Z, Pandey MK, Kushvaha SK, Roesky HW. Recent progress in transition metal complexes featuring silylene as ligands. Chem Commun (Camb) 2024. [PMID: 39119696 DOI: 10.1039/d4cc01930j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Silylenes, divalent silicon(II) compounds, once considered highly reactive and transient species, are now widely employed as stable synthons in main-group and coordination chemistry for myriad applications. The synthesis of stable silylenes represents a major breakthrough, which led to extensive exploration of silylenes in stabilizing low-valent main-group elements and as versatile ligands in coordination chemistry and catalysis. In recent years, the exploration of transition metal complexes stabilized with silylene ligands has captivated significant research attention. This is due to their robust σ-donor characteristics and capacity to stabilize transition metals in low valent states. It has also been demonstrated that the transition metal complexes of silylenes are effective catalysts for hydroboration, hydrosilylation, hydrogenation, hydrogen isotope exchange reactions, and small molecule activation chemistry. This review article focuses on the recent progress in the synthesis and catalytic application of transition metal complexes of silylenes.
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Affiliation(s)
- Zohreh Hendi
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Göttingen, 37077, Germany.
| | - Madhusudan K Pandey
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Göttingen, 37077, Germany.
| | - Saroj Kumar Kushvaha
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Göttingen, 37077, Germany.
| | - Herbert W Roesky
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Göttingen, 37077, Germany.
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2
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Madron du Vigné A, Cramer N. Streamlined synthetic assembly of α-chiral CAAC ligands and catalytic performance of their copper and ruthenium complexes. Chem Sci 2024:d4sc04278f. [PMID: 39129771 PMCID: PMC11306997 DOI: 10.1039/d4sc04278f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Accepted: 07/23/2024] [Indexed: 08/13/2024] Open
Abstract
The unique electronic and steric parameters of chiral cyclic alkyl amino carbene (CAAC) ligands render them appealing steering ligands for enantioselective transition-metal catalyzed transformations. Due to the lack of efficient synthetic strategies to access particularly attractive α-chiral CAACs assessment and exploitation of their full synthetic potential remain difficult. Herein, we report a streamlined strategy to assemble a library of diastereo- and enantiomerically pure CAAC ligands featuring the notoriously difficult to access α-quaternary stereogenic centers. A tailored Julia-Kocienski olefination reagent allows the Claisen-rearrangement to be leveraged as an expedient route to form the synthetically pivotal racemic α-chiral methallyl aldehydes. Subsequent condensation with chiral amines and further cyclization provided a library of diastereomeric mixtures of the targeted ligand precursors. The CAAC salts as well as their corresponding metal complexes are conveniently separable by standard silica gel flash chromatography closing a long-standing accessibility gap in chiral CAAC ligands with proximal α-chirality. The rapid availability of both diastereomers enables testing of the relevance and synergistic effects of two chiral centers on the ligand in catalytic applications. A broad range of metal complexes with copper, gold, rhodium and ruthenium were obtained and structurally analyzed. The catalytic performances of the corresponding chiral CAAC copper and ruthenium complexes were assessed in enantioselective conjugate borylations and asymmetric ring closing metathesis, displaying selectivities of up 95 : 5 er.
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Affiliation(s)
- Adrien Madron du Vigné
- Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Nicolai Cramer
- Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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3
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Huang M, Li K, Zhang Z, Zhou J. Antimony Redox Catalysis: Hydroboration of Disulfides through Unique Sb(I)/Sb(III) Redox Cycling. J Am Chem Soc 2024; 146:20432-20438. [PMID: 38981106 DOI: 10.1021/jacs.4c05905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
The stibinidene ArSbI (Ar = [2,6-(tBuN═CH)2-C6H3], 1) reacts with S2Tol2 (Tol = p-tolyl) to form ArSbIII(STol)2 (2), which upon treatment with pinacolborane, regenerates 1. These processes unveil an unprecedented antimony redox catalysis involving Sb(I)/Sb(III) cycling for the hydroboration of organic disulfides. Elementary reaction studies and density functional theory calculations support that the catalysis mimics transition metal processes, proceeding through oxidative addition, ligand metathesis, and reductive elimination. The thiophenols and sulfidoborates generated from the hydroboration of disulfides react in situ with α,β-unsaturated carbonyl compounds with the assistance of 1 as a base catalyst. These tandem reactions establish a one-pot synthetic method for β-sulfido carbonyl compounds, in which a stibinidene functions as a redox catalyst and a base catalyst successively, illustrating the versatility and efficiency of antimony catalysis in organic synthesis.
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Affiliation(s)
- Minghao Huang
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
| | - Kunlong Li
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
| | - Zichen Zhang
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
| | - Jiliang Zhou
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
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4
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He M, Hu C, Wei R, Wang XF, Liu LL. Recent advances in the chemistry of isolable carbene analogues with group 13-15 elements. Chem Soc Rev 2024; 53:3896-3951. [PMID: 38436383 DOI: 10.1039/d3cs00784g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Carbenes (R2C:), compounds with a divalent carbon atom containing only six valence shell electrons, have evolved into a broader class with the replacement of the carbene carbon or the RC moiety with main group elements, leading to the creation of main group carbene analogues. These analogues, mirroring the electronic structure of carbenes (a lone pair of electrons and an empty orbital), demonstrate unique reactivity. Over the last three decades, this area has seen substantial advancements, paralleling the innovations in carbene chemistry. Recent studies have revealed a spectrum of unique carbene analogues, such as monocoordinate aluminylenes, nitrenes, and bismuthinidenes, notable for their extraordinary properties and diverse reactivity, offering promising applications in small molecule activation. This review delves into the isolable main group carbene analogues that are in the forefront from 2010 and beyond, spanning elements from group 13 (B, Al, Ga, In, and Tl), group 14 (Si, Ge, Sn, and Pb) and group 15 (N, P, As, Sb, and Bi). Specifically, this review focuses on the potential amphiphilic species that possess both lone pairs of electrons and vacant orbitals. We detail their comprehensive synthesis and stabilization strategies, outlining the reactivity arising from their distinct structural characteristics.
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Affiliation(s)
- Mian He
- Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis and Research Center for Chemical Biology and Omics Analysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Chaopeng Hu
- Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis and Research Center for Chemical Biology and Omics Analysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Rui Wei
- Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis and Research Center for Chemical Biology and Omics Analysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Xin-Feng Wang
- Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis and Research Center for Chemical Biology and Omics Analysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Liu Leo Liu
- Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis and Research Center for Chemical Biology and Omics Analysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
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5
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Vermersch F, Wang VT, Abdellaoui M, Jazzar R, Bertrand G. Ambiphilicity of ring-expanded N-heterocyclic carbenes. Chem Sci 2024; 15:3707-3710. [PMID: 38455021 PMCID: PMC10915854 DOI: 10.1039/d3sc04543a] [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: 08/29/2023] [Accepted: 01/18/2024] [Indexed: 03/09/2024] Open
Abstract
N-heterocyclic carbenes, such as imidazole-2-ylidenes and imidazolin-2-ylidenes, the popular class of singlet carbenes introduced by Arduengo in 1991 have not been shown to be ambiphilic owing to the two σ-withdrawing, π-donating amino groups flanking the carbene centre. However, our experimental data suggest that ring-expanded N-heterocyclic carbenes (RE-NHCs), especially the seven and eight membered rings, are significantly ambiphilic. Our results also show that the steric environment in RE-NHCs can become a determining factor for controlling the E-H bond activation.
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Affiliation(s)
- François Vermersch
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093-0358 USA
| | - Victor T Wang
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093-0358 USA
| | - Mehdi Abdellaoui
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093-0358 USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093-0358 USA
| | - Guy Bertrand
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093-0358 USA
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6
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Zhao Q, Rahman MM, Zhou T, Yang S, Lalancette R, Szostak R, Szostak M. Wingtip-Flexible N-Heterocyclic Carbenes: Unsymmetrical Connection between IMes and IPr. Angew Chem Int Ed Engl 2024; 63:e202318703. [PMID: 38135660 PMCID: PMC10922840 DOI: 10.1002/anie.202318703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/19/2023] [Accepted: 12/22/2023] [Indexed: 12/24/2023]
Abstract
IMes (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) and IPr (IPr=1,3- bis(2,6-diisopropylphenyl)imidazol-2-ylidene) represent by far the most frequently used N-heterocyclic carbene ligands in homogeneous catalysis, however, despite numerous advantages, these ligands are limited by the lack of steric flexibility of catalytic pockets. We report a new class of unique unsymmetrical N-heterocyclic carbene ligands that are characterized by freely-rotatable N-aromatic wingtips in the imidazol-2-ylidene architecture. The combination of rotatable N-CH2 Ar bond with conformationally-fixed N-Ar linkage results in a highly modular ligand topology, entering the range of geometries inaccessible to IMes and IPr. These ligands are highly reactive in Cu(I)-catalyzed β-hydroboration, an archetypal borylcupration process that has had a transformative impact on the synthesis of boron-containing compounds. The most reactive Cu(I)-NHC in this class has been commercialized in collaboration with MilliporeSigma to enable broad access of the synthetic chemistry community. The ligands gradually cover %Vbur geometries ranging from 37.3 % to 52.7 %, with the latter representing the largest %Vbur described for an IPr analogue, while retaining full flexibility of N-wingtip. Considering the modular access to novel geometrical space in N-heterocyclic carbene catalysis, we anticipate that this concept will enable new opportunities in organic synthesis, drug discovery and stabilization of reactive metal centers.
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Affiliation(s)
- Qun Zhao
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102 (United States)
| | - Md. Mahbubur Rahman
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102 (United States)
| | - Tongliang Zhou
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102 (United States)
| | - Shiyi Yang
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102 (United States)
| | - Roger Lalancette
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102 (United States)
| | - Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383 (Poland)
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102 (United States)
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7
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Takahashi S, Kamiyama S, Ishii A, Nakata N. Syntheses of Iminophosphomamido Chlorogermylenes and Their Complexation with a Rhodium(I) Complex. Chem Asian J 2024; 19:e202300968. [PMID: 38050920 DOI: 10.1002/asia.202300968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/07/2023]
Abstract
Three-coordinated chlorogermylenes of the type [Ph2 P(RN)2 ]GeCl (3: R=t Bu; 4: R=Dip=2,6-i Pr2 C6 H3 ), which bear an N,N-substituted iminophosphonamide ligand, were synthesized. The coordination behavior of 3 and 4 toward rhodium(I) complex was investigated. When 3 was treated with 1/2 of an equivalent of [RhCl(cod)]2 (cod=1,5-cyclooctadiene), the corresponding chlorogermylene-Rh(I) complex 5 was obtained as orange crystals. In contrast, the reaction of 4 with a half equivalent of [RhCl(cod)]2 under a CO atmosphere resulted in the formation of a five-membered germarhodacycle 7. Compounds 3, 4, 5, and 7 were characterized using NMR spectroscopies and single-crystal X-ray diffraction. Complex 5 can be employed as a catalyst for the hydrosilylation and hydroboration reactions of diphenylacetylene, thus demonstrating the utility of germylene ligands comparable to those of NHCs in the major transition metal catalytic processes.
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Affiliation(s)
- Shintaro Takahashi
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 225, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Shota Kamiyama
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 225, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Akihiko Ishii
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 225, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Norio Nakata
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 225, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
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8
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Touj N, Mazars F, Zaragoza G, Delaude L. Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes. Beilstein J Org Chem 2023; 19:1947-1956. [PMID: 38170157 PMCID: PMC10760461 DOI: 10.3762/bjoc.19.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
The synthesis of zwitterionic dithiocarboxylate adducts was achieved by deprotonating various aldiminium or 1,2,3-triazolium salts with a strong base, followed by the nucleophilic addition of the in situ-generated cyclic (alkyl)(amino) or mesoionic carbenes (CAACs or MICs) onto carbon disulfide. Nine novel compounds were isolated and fully characterized by 1H and 13C NMR, FTIR, and HRMS techniques. Moreover, the molecular structures of two CAAC·CS2 and two MIC·CS2 betaines were determined by X-ray diffraction analysis. The analytical data recorded for all these adducts were compared with those reported previously for related NHC·CS2 betaines derived from imidazolinium or (benz)imidazolium salts. Due to the absence of electronic communication between the CS2 unit and the orthogonal heterocycle, all the CAAC·CS2, MIC·CS2, and NHC·CS2 zwitterions displayed similar electronic properties and featured the same bite angle. Yet, their steric properties are liable to ample modifications by varying the exact nature of their cationic heterocycle and its substituents.
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Affiliation(s)
- Nedra Touj
- Laboratory of Catalysis, MolSys Research Unit, Université de Liège, Institut de chimie organique (B6a), Allée du six août 13, 4000 Liège, Belgium
| | - François Mazars
- Laboratory of Catalysis, MolSys Research Unit, Université de Liège, Institut de chimie organique (B6a), Allée du six août 13, 4000 Liège, Belgium
| | - Guillermo Zaragoza
- Unidad de Difracción de Rayos X, RIAIDT, Universidade de Santiago de Compostella, Edificio CACTUS, Campus Vida, 15782 Santiago de Compostela, Spain
| | - Lionel Delaude
- Laboratory of Catalysis, MolSys Research Unit, Université de Liège, Institut de chimie organique (B6a), Allée du six août 13, 4000 Liège, Belgium
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9
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Lu B, Zeng X. Phosphinidenes: Fundamental Properties and Reactivity. Chemistry 2023:e202303283. [PMID: 38108540 DOI: 10.1002/chem.202303283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 12/19/2023]
Abstract
Phosphinidenes are heavy congeners of nitrenes that have been broadly used as in situ reagents in synthetic phosphorus chemistry and also serve as versatile ligands in coordination with transition metals. However, the detection of free phosphinidenes is largely challenged by their high reactivity and also the lack of suitable synthetic methods, rendering the knowledge about the fundamental properties of this class of low-valent phosphorus compounds limited. Recently, an increasing number of free phosphinidenes bearing prototype structural and bonding properties have been prepared for the first time, thus enabling the exploration of their distinct reactivity from the nitrene analogues. This Concept article will discuss the experimental approaches for the generation of the highly unstable phosphinidenes and highlight their distinct reactivity from the nitrogen analogues so as to stimuate future studies about their potential applications in phosphorus chemistry.
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Affiliation(s)
- Bo Lu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China
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10
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Canac Y. Carbon-Phosphorus Ligands with Extreme Donating Character. CHEM REC 2023; 23:e202300187. [PMID: 37435947 DOI: 10.1002/tcr.202300187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/22/2023] [Indexed: 07/13/2023]
Abstract
Carbeniophosphines [R2 C+ -PR2 ] and phosphonium ylides [R3 P+ -CR2 - ] are two complementary classes of carbon-phosphorus based ligands defined by their unique donor properties. Indeed, while carbeniophosphines are electron-poor P-ligands due to the positioning of a positive charge near the coordinating P-atom, phosphonium ylides are electron-rich C-ligands due to the presence of a negatively charged coordinating C-atom. Based on this knowledge, this account summarizes our recent contribution on these two classes of carbon-phosphorus ligands, and in particular the strategies developed to lower the donor character of carbeniophosphines and enhance that of phosphonium ylides. This led us to design, at both extremities of the donating scale, extremely electron-poor P-ligands exemplified by imidazoliophosphonites [R2 C+ -P(OR)2 ] and dicarbeniophosphines [(R2 C+ )2 -PR], and extremely electron-rich C-ligands illustrated by pincer architectures exhibiting several phosphonium ylide donor extremities. In the context of carbon-phosphorus analogy, the closely related cases of ligands where the C-atom of a NHC ligand is in close proximity of two positive charges, and that of a phosphonium ylide coordinated through its P-atom are also discussed. An overview of the synthetic methods, coordinating properties, general reactivity and electronic structure of all these C,P-based species is presented here.
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Affiliation(s)
- Yves Canac
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077, Toulouse Cedex 4, France
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11
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Ohashi M, Ando K, Murakami S, Michigami K, Ogoshi S. N-Heterocyclic Carbenes with Polyfluorinated Groups at the 4- and 5-Positions from [3 + 2] Cycloadditions between Formamidinates and cis-1,2-Difluoroalkene Derivatives. J Am Chem Soc 2023; 145:23098-23108. [PMID: 37749910 DOI: 10.1021/jacs.3c06331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
We herein report the formation of fluorinated N-heterocyclic carbenes (NHCFs) that bear fluorine atoms at the 4- and 5-positions of the imidazol-2-ylidene ring. Treatment of sodium N,N'-bis(aryl)formamidinates with tetrafluoroethylene followed by the addition of LiBF4 induced a [3 + 2] cycloaddition to afford 4,5-difluorinated imidazolium salts, which served as the precursors for 4,5-difluorinated NHCs. A key feature of this procedure is its applicability to other perfluorinated compounds, which enabled us to incorporate polyfluorinated functional groups at 4- and 5-positions on the imidazol-2-ylidene skeleton. Thus, employing octafluorocyclopentene and hexafluorobenzene led to the formation of 4,4,5,5,6,6-hexafluoro-1,3-diaryl-3,4,5,6-tetrahydrocyclopenta[d]imidazolium (CypIPrF·HBF4) and 4,5,6,7-tetrafluoro-1,3-diarylbenzimidazolium (BIPrF·HBF4) salts, respectively. A thorough NMR analysis of these NHCFs, their selenium adducts, and their tricarbonyl nickel complexes, (NHCF)Ni(CO)3, demonstrated that the fluorine substituents, contrary to expectations, tend to act as electron donors owing to the considerable positive mesomeric effect, while the perfluorocyclopentene-fused and tetrafluorobenzo-fused rings are pure electron acceptors due to their strong negative inductive effect. The unique and increased π-accepting character of the perfluorocyclopentene-fused and tetrafluorobenzo-fused NHCFs in both stoichiometric and catalytic reactions is further demonstrated by employing (NHCF)Ni(CO)3 and (NHCF)AuCl species, respectively. Moreover, an analysis of the % buried volume (%Vbur) values clearly suggests that the modification of the NHC backbone with polyfluorinated groups can drastically alter the electronic properties of the NHC ligand without substantially changing its steric properties. Our experimental results were further corroborated by a series of computational calculations.
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Affiliation(s)
- Masato Ohashi
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, Sakai 599-8531 Osaka, Japan
| | - Kota Ando
- Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita 565-0871 Osaka, Japan
| | - Shoichi Murakami
- Department of Chemistry, Faculty of Science, Osaka Prefecture University, Sakai 599-8531 Osaka, Japan
| | - Kenichi Michigami
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, Sakai 599-8531 Osaka, Japan
| | - Sensuke Ogoshi
- Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita 565-0871 Osaka, Japan
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12
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Heinz M, Arrowsmith M, Schweizer JI, Krummenacher I, Holthausen MC, Braunschweig H. Experimental and Computational Study of a Confirmed Borylene-to-Diborene Dimerization. J Am Chem Soc 2023; 145:22685-22696. [PMID: 37802099 DOI: 10.1021/jacs.3c07979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
While the dimerization of heavier group 13 carbene analogues to the corresponding alkene analogues is known and relatively well understood, the dimerization of dicoordinate borylenes (LRB:, L = neutral donor; R = anionic substituent) to the corresponding diborenes (LRB═BRL) has never been directly observed. In this study we present the first example of a formal borylene-to-diborene dimerization through abstraction of a labile phosphine ligand from the tricoordinate hydroborylene precursor (CAAC)(Me3P)BH (CAAC = cyclic alkyl(amino)carbene) by bulky Lewis-acidic dihaloboranes (BX2Y, X = Cl, Br, Y = aryl, boryl), generating the corresponding dihydrodiborene (CAAC)HB═BH(CAAC) and (Me3P)BX2Y as the byproduct. An in-depth experimental and computational mechanistic analysis shows that this seemingly simple process (2 LL'BH + 2 BX2Y → LHB═BHL + 2 L'BX2Y) is in fact based on a complex sequence of finely tuned processes, involving the one-electron oxidation of and PMe3 abstraction from the borylene precursor by BX2Y, multiple halide transfers between (di)boron intermediates and BX2Y/[BX3Y]-, and multiple one-electron redox processes between diboron intermediates and the borylene precursor, which make the reaction ultimately autocatalytic in [(CAAC)(Me3P)BH]•+. The findings suggest that [LBXR]• boryl radicals are more likely coupling partners than dicoordinate LRB: borylenes in the reductive coupling of base-stabilized LBX2R boranes to LRB═BRL diborenes.
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Affiliation(s)
- Myron Heinz
- Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Merle Arrowsmith
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Julia I Schweizer
- Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Max C Holthausen
- Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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13
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Nguyen TH, Pauly C, Kent GT, Wu G, Hayton TW. Dimerization and ring-opening in bis(diisopropylamino)cyclopropenylidene (BAC) mediated by [U(NR 2) 3(CCPh)] (R = SiMe 3). Dalton Trans 2023; 52:13868-13871. [PMID: 37751280 DOI: 10.1039/d3dt02741d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Addition of 2 equiv. of bis(diisopropylamino)cyclopropenylidene (BAC) to [U(NR2)3(CCPh)] (1, R = SiMe3), in Et2O, results in formation of [cyclo-N(iPr)C(Me)2CH(NiPr2)C{CHC3(NiPr2)2}][U(NR2)2(N(SiMe3)SiMe2CH2)(CCPh)] (2) in moderate isolated yield. Complex 2 is the result of coupling and protonation of two BAC molecules, where complex 1 contributes the required proton. It was characterized by NMR spectroscopy and X-ray crystallography and represents a new mode of reactivity of the cyclopropenylidene fragment.
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Affiliation(s)
- Thien H Nguyen
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Christophe Pauly
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Greggory T Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
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14
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Wang B, Chen W, Yang J, Lu L, Liu J, Shen L, Wu D. N-Heterocyclic imine-based bis-gallium(I) carbene analogs featuring a four-membered Ga 2N 2 ring. Dalton Trans 2023; 52:12454-12460. [PMID: 37594454 DOI: 10.1039/d3dt00782k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
A combination of Ga(I) centers as important building blocks and scaffolds containing N-heterocyclic imines gives new insights into low-valent Ga chemistry. In this study, a mixture of LDipNLi (LDip = 1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene), tBuOK, and Cp*Ga (Cp* = pentamethylcyclopentadienyl) in toluene afforded [LDipN-Ga]2 (1) via salt metathesis. X-ray structure analysis of 1 revealed a four-membered Ga2N2 ring, and DFT studies indicated the presence of a lone pair at each Ga center. In addition, compound 1 demonstrated diverse reactivities towards methyl trifluoromethanesulfonate, diphenyl disulfide, 9,10-phenanthrenequinone, and ECl2 (E = Ge or Sn).
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Affiliation(s)
- Bing Wang
- College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
| | - Wenhao Chen
- College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
| | - Jiangnan Yang
- College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
| | - Linfang Lu
- College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
| | - Jiyong Liu
- Department of Chemistry, Zhejiang University, Hangzhou 310028, China
| | - Liang Shen
- College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
| | - Di Wu
- College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
- Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables, Hubei Engineering University, Hubei 432000, China
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15
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Rahman M, Gao P, Zhao Q, Lalancette R, Szostak R, Szostak M. [Au(Np #)Cl]: Highly Reactive and Broadly Applicable Au(I)─NHC Catalysts for Alkyne π-Activation Reactions. Catal Sci Technol 2023; 13:5131-5139. [PMID: 38464950 PMCID: PMC10923537 DOI: 10.1039/d3cy00717k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Cationic Au(I)─NHC (NHC = N-heterocyclic carbene) complexes have become an important class of catalysts for alkyne π-activation reactions in organic synthesis. In particular, these complexes are characterized by high stability of catalytic species engendered by strong σ-donation and metal backbonding. Herein, we report the synthesis and characterization of well-defined [Au(NHC)Cl] complexes featuring recently discovered IPr# family of ligands that hinge upon modular peralkylation of aniline. These ligands have been commercialized in collaboration with MilliporeSigma (IPr#: 915653; Np#: 915912; BIAN-IPr#: 916420). Evaluation of the [Au(NHC)Cl] complexes in a series of Au(I)─NHC-catalyzed π-functionalizations of alkynes, such as hydrocarboxylation, hydroamination and hydration, resulted in the identification of wingtip-flexible [Au(Np#)Cl] as a highly reactive and broadly applicable catalyst with the re-activity outperforming the classical [Au(IPr)Cl] and [Au(IPr*)Cl] complexes. The utility of this catalyst has been demonstrated in the direct late-stage derivatization of complex pharmaceuticals. Structural and computational studies were conducted to determine steric effects, frontier molecular orbitals and bond orders of this class of catalysts. Considering the attractive features of well-defined Au(I)─NHC complexes, we anticipate that this class of bulky and wingtip-flexible Au(I)─NHCs based on the modular peralkylated naphthylamine scaffold will find broad application in π-functionalization of alkynes in various areas of organic synthesis and catalysis.
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Affiliation(s)
- Mahbubur Rahman
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
| | - Pengcheng Gao
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
| | - Qun Zhao
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
| | - Roger Lalancette
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
| | - Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
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16
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Marigo N, Morgenstern B, Biffis A, Munz D. (CAAC)Pd(py) Catalysts Disproportionate to Pd(CAAC) 2. Organometallics 2023; 42:1567-1572. [PMID: 37448536 PMCID: PMC10337258 DOI: 10.1021/acs.organomet.3c00150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Indexed: 07/15/2023]
Abstract
Palladium complexes with one N-heterocyclic carbene (NHC) and a pyridine ancillary ligand are powerful cross-coupling precatalysts. Herein, we report such complexes with a cyclic (alkyl)(amino)carbene (CAAC) ligand replacing the NHC. We find that the alleged reduced form, (CAAC)Pd(py), disproportionates to the (CAAC)2Pd0 complex and palladium nanoparticles. This notwithstanding, they are potent catalysts in the Buchwald-Hartwig amination with aryl chlorides under mild conditions (60 °C). In the presence of dioxygen, these complexes catalyze the formation of diazenes from anilines. The catalytic activities of the NHC- and CAAC-supported palladium(0) and palladium(II) complexes are similar in the cross-coupling reaction, yet the CAAC complexes are superior for diazene formation.
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Affiliation(s)
- Nicola Marigo
- Coordination Chemistry, Saarland University, Campus C4.1, Saarbrücken D-66123, Germany
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova I-35131, Italy
| | - Bernd Morgenstern
- Coordination Chemistry, Saarland University, Campus C4.1, Saarbrücken D-66123, Germany
| | - Andrea Biffis
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova I-35131, Italy
| | - Dominik Munz
- Coordination Chemistry, Saarland University, Campus C4.1, Saarbrücken D-66123, Germany
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17
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Singh J, Sharma S, Prakasham AP, Rajaraman G, Ghosh P. Accessing Bioactive Hydrazones by the Hydrohydrazination of Terminal Alkynes Catalyzed by Gold(I) Acyclic Aminooxy Carbene Complexes and Their Gold(I) Arylthiolato and Gold(III) Tribromo Derivatives: A Combined Experimental and Computational Study. ACS OMEGA 2023; 8:21042-21073. [PMID: 37323414 PMCID: PMC10268297 DOI: 10.1021/acsomega.3c01925] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/05/2023] [Indexed: 06/17/2023]
Abstract
Hydrohydrazination of terminal alkynes with hydrazides yielding hydrazones 5-14 were successfully catalyzed by a series of gold(I) acyclic aminooxy carbene complexes of the type [{(4-R2-2,6-t-Bu2-C6H2O)(N(R1)2)}methylidene]AuCl, where R2 = H, R1 = Me (1b); R2 = H, R1 = Cy (2b); R2 = t-Bu, R1 = Me (3b); R2 = t-Bu, R1 = Cy (4b). The mass spectrometric evidence corroborated the existence of the catalytically active solvent-coordinated [(AAOC)Au(CH3CN)]SbF6 (1-4)A species and the acetylene-bound [(AAOC)Au(HC≡CPhMe)]SbF6 (3B) species of the proposed catalysis cycle. The hydrohydrazination reaction was successfully employed in synthesizing several bioactive hydrazone compounds (15-18) with anticonvulsant properties using a representative precatalyst (2b). The DFT studies favored the 4-ethynyltoluene (HC≡CPhMe) coordination pathway over the p-toluenesulfonyl hydrazide (NH2NHSO2C6H4CH3) coordination pathway, and that proceeded by a crucial intermolecular hydrazide-assisted proton transfer step. The gold(I) complexes (1-4)b were synthesized from the {[(4-R2-2,6-t-Bu2-C6H2O)(N(R1)2)]CH}+OTf- (1-4)a by treatment with (Me2S)AuCl in the presence of NaH as a base. The reactivity studies of (1-4)b yielded the gold(III) [{(4-R2-2,6-t-Bu2-C6H2O)(N(R1)2)}methylidene]AuBr3 (1-4)c complexes upon reaction with molecular bromine and the gold(I) perfluorophenylthiolato derivatives, [{(4-R2-2,6-t-Bu2-C6H2O)(N(R1)2)}methylidene]AuSC6F5 (1-4)d, upon treatment with C6F5SH.
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18
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Mageed AH, Al-Ameed K. Synthesis, structural studies and computational evaluation of cyclophanes incorporating imidazole-2-selones. RSC Adv 2023; 13:17282-17296. [PMID: 37323874 PMCID: PMC10265033 DOI: 10.1039/d3ra02913a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023] Open
Abstract
We report new cyclophanes containing imidazole-2-selone groups linked by xylylene rings. A set of imidazole-2-selone cyclophanes is synthesized by reaction corresponding to imidazolium cyclophanes with selenium in the presence of K2CO3. The structural behavior of the new imidazole-2-selone cyclophanes was determined by 1H and 13C NMR spectra and X-ray diffraction studies. Cyclophanes incorporating o-xylylene or mesitylene-m-cyclophane linked by selone groups were mutually syn in both the solid state and solution, and the cyclophanes showed a conformation similar to the cone conformation of calix[4]arenes. Cyclophanes incorporating p-xylylene or m-xylylene linked by selone groups showed two conformations in the solution: one mutually syn and the other mutually anti. There was no interconversion for both conformations observed on the NMR timescale. In the solid state, three conformations were detected for the p-xylylene-linked cyclophane: one is mutually syn and the other two are mutually anti and partial cone conformations. In the m-xylylene-linked case, only anti-conformation was characterized in the solid state. A density functional analysis was conducted to interpret the stability of the studied compounds and shed light on their origin. The energy preference analysis is in consistent agreement with the observed geometries and their co-existence.
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Affiliation(s)
- Ahmed Hassoon Mageed
- Department of Chemistry, Faculty of Science, The University of Kufa P. O. Box 21 Najaf 54001 Iraq
| | - Karrar Al-Ameed
- Department of Chemistry, Faculty of Science, The University of Kufa P. O. Box 21 Najaf 54001 Iraq
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19
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Cao Y, Mieres-Perez J, Lucht K, Ulrich I, Schweer P, Sanchez-Garcia E, Morgenstern K, Sander W. C-C Coupling of Carbene Molecules on a Metal Surface in the Presence of Water. J Am Chem Soc 2023; 145:11544-11552. [PMID: 37207364 DOI: 10.1021/jacs.2c12274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A novel surface-confined C-C coupling reaction involving two carbene molecules and a water molecule was studied by scanning tunneling microscopy in real space. Carbene fluorenylidene was generated from diazofluorene in the presence of water on a silver surface. While in the absence of water, fluorenylidene covalently binds to the surface to form a surface metal carbene, and water can effectively compete with the silver surface in reacting with the carbene. Water molecules in direct contact with fluorenylidene protonate the carbene to form the fluorenyl cation before the carbene can bind to the surface. In contrast, the surface metal carbene does not react with water. The fluorenyl cation is highly electrophilic and draws electrons from the metal surface to generate the fluorenyl radical which is mobile on the surface at cryogenic temperatures. The final step in this reaction sequence is the reaction of the radical with a remaining fluorenylidene molecule or with diazofluorene to produce the C-C coupling product. Both a water molecule and the metal surface are essential for the consecutive proton and electron transfer followed by C-C coupling. This C-C coupling reaction is unprecedented in solution chemistry.
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Affiliation(s)
- Yunjun Cao
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Joel Mieres-Perez
- Technische Universität Dortmund, Lehrstuhl für Computational Bioengineering, Dortmund 44227, Germany
| | - Karsten Lucht
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Iris Ulrich
- Ruhr-Universität Bochum, Lehrstuhl für Organische Chemie II, Universitätsstr. 150, Bochum D-44801, Germany
| | - Paul Schweer
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Elsa Sanchez-Garcia
- Technische Universität Dortmund, Lehrstuhl für Computational Bioengineering, Dortmund 44227, Germany
| | - Karina Morgenstern
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Wolfram Sander
- Ruhr-Universität Bochum, Lehrstuhl für Organische Chemie II, Universitätsstr. 150, Bochum D-44801, Germany
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20
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Rahman MM, Meng G, Bisz E, Dziuk B, Lalancette R, Szostak R, Szostak M. I tOct (I tOctyl) - pushing the limits of I tBu: highly hindered electron-rich N-aliphatic N-heterocyclic carbenes. Chem Sci 2023; 14:5141-5147. [PMID: 37206400 PMCID: PMC10189875 DOI: 10.1039/d3sc01006f] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/15/2023] [Indexed: 05/21/2023] Open
Abstract
ItBu (ItBu = 1,3-di-tert-butylimidazol-2-ylidene) represents the most important and most versatile N-alkyl N-heterocyclic carbene available in organic synthesis and catalysis. Herein, we report the synthesis, structural characterization and catalytic activity of ItOct (ItOctyl), C2-symmetric, higher homologues of ItBu. The new ligand class, including saturated imidazolin-2-ylidene analogues has been commercialized in collaboration with MilliporeSigma: ItOct, 929 298; SItOct, 929 492 to enable broad access of the academic and industrial researchers within the field of organic and inorganic synthesis. We demonstrate that replacement of the t-Bu side chain with t-Oct results in the highest steric volume of N-alkyl N-heterocyclic carbenes reported to date, while retaining the electronic properties inherent to N-aliphatic ligands, such as extremely strong σ-donation crucial to the reactivity of N-alkyl N-heterocyclic carbenes. An efficient large-scale synthesis of imidazolium ItOct and imidazolinium SItOct carbene precursors is presented. Coordination chemistry to Au(i), Cu(i), Ag(i) and Pd(ii) as well as beneficial effects on catalysis using Au(i), Cu(i), Ag(i) and Pd(ii) complexes are described. Considering the tremendous importance of ItBu in catalysis, synthesis and metal stabilization, we anticipate that the new class of ItOct ligands will find wide application in pushing the boundaries of new and existing approaches in organic and inorganic synthesis.
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Affiliation(s)
- Md Mahbubur Rahman
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
| | - Guangrong Meng
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
| | - Elwira Bisz
- Department of Chemistry, Opole University 48 Oleska Street Opole 45-052 Poland
| | - Błażej Dziuk
- Department of Chemistry, Wroclaw University of Science and Technology Norwida 4/6 14 Wroclaw 50-373 Poland
| | - Roger Lalancette
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
| | - Roman Szostak
- Department of Chemistry, Wroclaw University F. Joliot-Curie 14 Wroclaw 50-383 Poland
| | - Michal Szostak
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
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21
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Coordination Versatility of NHC-metal Topologies in Asymmetric Catalysis: Synthetic Insights and Recent Trends. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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22
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Baschieri A, Mazzoni R, Cesari C, Zacchini S, Pecorari D, Sambri L. Ruthenium (0) Complexes with NHC Tetrazolylidene Ligands: Synthesis, Characterization and Reactivity. Inorganica Chim Acta 2023. [DOI: 10.1016/j.ica.2023.121472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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23
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Majumder A, Naskar R, Roy P, Mondal B, Garai S, Maity R. A naphthalene-based heterobimetallic triazolylidene Ir III/Pd II complex: regioselective to regiospecific C-H activation, tandem catalysis and a copper-free Sonogashira reaction. Dalton Trans 2023; 52:2272-2281. [PMID: 36723111 DOI: 10.1039/d2dt03508a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Heterobimetallic complexes featuring mesoionic carbene (MIC) donor ligands are gaining enormous popularity in tandem catalysis owing to the combined action of two different metal centers during catalysis. A rare version of the heterobimetallic PdII/IrIII complex possessing a cyclometalated mesoionic carbene (MIC) ligand is presented along with the analogous homodinuclear PdII complex. A sterically controlled regiospecific cyclometalation towards the formation of a six-membered ring complex over a five-membered ring complex has been performed using a naphthalene-based bis-MIC ligand platform. The interplay between regioselective vs. regiospecific C-H bond activation for the synthesis of cyclometalated IrIII complexes has also been demonstrated using the corresponding naphthyl-derived mono-imidazolylidene ligand. Both homodinuclear PdII and heterobimetallic PdII/IrIII complexes have been characterized using standard spectroscopic techniques including 1H, 13C{1H}, 2D correlation NMR spectroscopy and ESI mass spectrometry. The structure of the cyclometalated heterobimetallic complex has been established by single crystal XRD. The heterobimetallic complex has been employed as a pre-catalyst in the tandem Suzuki-Miyaura/transfer hydrogenation reaction and the homobimetallic PdII complex has been successfully employed as a catalyst in both the Sonogashira coupling and α-arylation of 1-methyl-2-oxindole.
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Affiliation(s)
- Adhir Majumder
- Department of Chemistry, University of Calcutta, Kolkata, West Bengal, 700009, India.
| | - Rajat Naskar
- Department of Chemistry, University of Calcutta, Kolkata, West Bengal, 700009, India.
| | - Pallabi Roy
- Department of Chemistry, University of Calcutta, Kolkata, West Bengal, 700009, India.
| | - Bhaskar Mondal
- Department of Chemistry, University of Calcutta, Kolkata, West Bengal, 700009, India.
| | - Somenath Garai
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh, India
| | - Ramananda Maity
- Department of Chemistry, University of Calcutta, Kolkata, West Bengal, 700009, India.
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24
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Zhang Y, Wu L, Wang H. Application of N-heterocyclic silylenes in low-valent group 13, 14 and 15 chemistry. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Peltier JL, Serrato MR, Thery V, Pecaut J, Tomás-Mendivil E, Bertrand G, Jazzar R, Martin D. An air-stable radical with a redox-chameleonic amide. Chem Commun (Camb) 2023; 59:595-598. [PMID: 36524847 DOI: 10.1039/d2cc05404c] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An air-stable (amino)(amido)radical was synthesized by reacting a cyclic (alkyl)(amino)carbene with carbazoyl chloride, followed by one-electron reduction. We show that an adjacent radical center weakens the amide bond. It enables the amino group to act as a strong acceptor under steric contraint, thus enhancing the stabilizing capto-dative effect.
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Affiliation(s)
- Jesse L Peltier
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - Melinda R Serrato
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - Valentin Thery
- University Grenoble Alpes, CNRS, DCM, Grenoble 38000, France.
| | - Jacques Pecaut
- University Grenoble Alpes, CEA, CNRS, INAC-SyMMES, UMR 5819, Grenoble 38000, France
| | | | - Guy Bertrand
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - David Martin
- University Grenoble Alpes, CNRS, DCM, Grenoble 38000, France.
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26
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Philipp MSM, Bertermann R, Radius U. Activation of Ge-H and Sn-H Bonds with N-Heterocyclic Carbenes and a Cyclic (Alkyl)(amino)carbene. Chemistry 2023; 29:e202202493. [PMID: 36177710 PMCID: PMC10100474 DOI: 10.1002/chem.202202493] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Indexed: 01/14/2023]
Abstract
A study of the reactivity of several N-heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene 1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene (cAACMe ) with the group 14 hydrides GeH2 Mes2 and SnH2 Me2 (Me=CH3 , Mes=1,3,5-(CH3 )3 C6 H2 ) is presented. The reaction of GeH2 Mes2 with cAACMe led to the insertion of cAACMe into one Ge-H bond to give cAACMe H-GeHMes2 (1). If 1,3,4,5-tetramethyl-imidazolin-2-ylidene (Me2 ImMe ) was used as the carbene, NHC-mediated dehydrogenative coupling occurred, which led to the NHC-stabilized germylene Me2 ImMe ⋅GeMes2 (2). The reaction of SnH2 Me2 with cAACMe also afforded the insertion product cAACMe H-SnHMe2 (3), and reaction of two equivalents Me2 ImMe with SnH2 Me2 gave the NHC-stabilized stannylene Me2 ImMe ⋅SnMe2 (4). If the sterically more demanding NHCs Me2 ImMe , 1,3-di-isopropyl-4,5-dimethyl-imidazolin-2-ylidene (iPr2 ImMe ) and 1,3-bis-(2,6-di-isopropylphenyl)-imidazolin-2-ylidene (Dipp2 Im) were employed, selective formation of cyclic oligomers (SnMe2 )n (5; n=5-8) in high yield was observed. These cyclic oligomers were also obtained from the controlled decomposition of cAACMe H-SnHMe2 (3).
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Affiliation(s)
- Michael S M Philipp
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Udo Radius
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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27
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Amouri H. Luminescent Complexes of Platinum, Iridium, and Coinage Metals Containing N-Heterocyclic Carbene Ligands: Design, Structural Diversity, and Photophysical Properties. Chem Rev 2023; 123:230-270. [PMID: 36315851 DOI: 10.1021/acs.chemrev.2c00206] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The employment of N-heterocyclic carbenes (NHCs) to design luminescent metal compounds has been the focus of recent intense investigations because of the strong σ-donor properties, which bring stability to the whole system and tend to push the d-d dark states so high in energy that they are rendered thermally inaccessible, thereby generating highly emissive complexes for useful applications such as organic light-emitting diodes (OLEDs), or featuring chiroptical properties, a field that is still in its infancy. Among the NHC complexes, those containing organic chromophores such as naphthalimide, pyrene, and carbazole exhibit rich emission behavior and thus have attracted extensive interest in the past five years, especially carbene coinage metal complexes with carbazolate ligands. In this review, the design strategies of NHC-based luminescent platinum and iridium complexes with large spin-orbit-coupling (SOC) are described first. Subsequent paragraphs illustrate the recent advances of luminescent coinage metal complexes with nucleophilic- and electrophilic-based carbenes based on silver, gold, and copper metal complexes that have the ability to display rich excited state emissions in particular via thermally activated delayed fluorescence (TADF). The luminescence mechanism and excited state dynamics are also described. We then summarize the advance of NHC-metal complexes in the aforementioned fields in recent years. Finally, we propose the development trend of this fast-growing field of luminescent NHC-metal complexes.
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Affiliation(s)
- Hani Amouri
- CNRS, IPCM (UMR 8232), Sorbonne Université-Faculté des Sciences et Ingénerie Campus Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris, Cedex 05, France
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28
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Jiao J, Yang W, Wang X. α-Aminocarbene-Mediated Si-H Insertion: Deoxygenative Silylation of Aromatic Amides with Silanes. J Org Chem 2023; 88:594-601. [PMID: 36521058 DOI: 10.1021/acs.joc.2c02649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
While metal carbene-mediated Si-H insertion reactions have become a powerful strategy to build new C-Si bonds, the utilization of α-aminocarbene intermediates generated from readily available precursors in the Si-H insertion reaction remains a longstanding challenge. Herein, we develop a practical and general strategy to synthesize α-aminosilanes through a deoxygenative cross-coupling of amides and silanes mediated by Sm/SmI2. Given the simplicity and versatility, this methodology represents a fascinating example for the effective utilization of inert amides as α-aminocarbene precursors in organic synthesis.
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Affiliation(s)
- Jiwen Jiao
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Wenhan Yang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.,College of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610068, China
| | - Xiaoming Wang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.,School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou 310024, China
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29
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Tyagi A, Mondal S, Anmol, Tiwari V, Karmakar T, Kundu S. Understanding cyclic(alkyl)(amino)carbene-copper complex catalysed N-H and O-H bond addition to electron deficient olefins. Chem Commun (Camb) 2022; 59:110-113. [PMID: 36477167 DOI: 10.1039/d2cc05613e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The hydroamination of electron-deficient olefins was carried out using the (CAAC)Cu-Cl (CAAC = cyclic (alkyl)(amino)carbene) catalyst with an excellent yield at room temperature and under an open atmosphere. Furthermore, the catalyst shows excellent efficiency in the hydroaryloxylation and hydroalkoxylation of alkenes under mild conditions. The efficiency of the catalyst was tested for a wide range of substrates with different electronic and steric functionalities. Detailed computational studies have been carried out to understand the mechanism of these Cu(I) catalyzed reactions, which revealed that the reaction proceeds via either a four-membered or a six-membered cyclic transition state containing the copper ion.
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Affiliation(s)
- Akshi Tyagi
- Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India.
| | - Sunita Mondal
- Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India.
| | - Anmol
- Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India.
| | - Vikas Tiwari
- Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India.
| | - Tarak Karmakar
- Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India.
| | - Subrata Kundu
- Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India.
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30
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Chu W, Zhou T, Bisz E, Dziuk B, Lalancette R, Szostak R, Szostak M. CAAC-IPr*: easily accessible, highly sterically-hindered cyclic (alkyl)(amino)carbenes. Chem Commun (Camb) 2022; 58:13467-13470. [PMID: 36382995 PMCID: PMC9737351 DOI: 10.1039/d2cc05668b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
IPr* (IPr* = 1,3-bis(2,6-bis(diphenylmethyl)-4-methylphenyl)imidazol-2-ylidene) has emerged as a powerful highly hindered and sterically-flexible ligand platform for transition-metal catalysis. CAACs (CAAC = cyclic (al-kyl)(amino)carbenes) have gained major attention as strongly electron-rich carbon analogues of NHCs (NHC = N-heterocyclic carbene) with broad applications in both industry and academia. Herein, we report a merger of CAAC ligands with highly-hindered IPr*. The efficient synthesis, electronic characterization and application in model Cu-catalyzed hydroboration of alkynes is described. The ligands are strongly electron-rich, bulky and flexible around the N-Ar wingtip. The availability of various IPr* and CAAC templates offers a significant potential to expand the existing arsenal of NHC ligands to electron-rich bulky architectures with critical applications in metal stabilization and catalysis.
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Affiliation(s)
- Wenchao Chu
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA.
| | - Tongliang Zhou
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA.
| | - Elwira Bisz
- Department of Chemistry, Opole University, 48 Oleska Street, Opole 45-052, Poland
| | - Błażej Dziuk
- Faculty of Chemistry, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Roger Lalancette
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA.
| | - Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA.
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31
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Padunnappattu A, Duhayon C, César V, Canac Y. Bis( N-cyclopropenio)-imidazol-2-ylidene: An N-Heterocyclic Carbene Bearing Two N-Cationic Substituents. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ajay Padunnappattu
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
| | - Carine Duhayon
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
| | - Vincent César
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
| | - Yves Canac
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
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32
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Rahman MM, Zhao Q, Meng G, Szostak R, Szostak M. [Ni(Np#)(η5-Cp)Cl]: Flexible, Sterically Bulky, Well-Defined, Highly Reactive Complex for Nickel-Catalyzed Cross-Coupling. Organometallics 2022; 41:2597-2604. [PMID: 38031540 PMCID: PMC10686542 DOI: 10.1021/acs.organomet.2c00316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ni-NHCs (NHC = N-heterocyclic carbene) have become an increasingly important class of complexes in catalysis and organometallic chemistry owing to the beneficial features of nickel as an abundant 3d metal. However, the development of well-defined and air-stable Ni-NHC complexes for cross-coupling has been more challenging than with Pd-NHC catalysis because of less defined reactivity trends of NHC ancillary ligands coordinated to Ni. Herein, we report the synthesis and catalytic activity of well-defined [Ni(NHC)(η5-Cp)Cl] complexes bearing recently commercialized IPr# family of ligands (Sigma Aldrich) and versatile cyclopentadienyl throw-away ligand. The NHC ligands, IPr#, Np# and BIAN-IPr#, are prepared by robust and modular peralkylation of anilines. Most crucially, we identified [Ni(Np#)(η5-Cp)Cl] as a highly reactive [Ni(NHC)(η5-Cp)Cl] complex, with the reactivity outperforming the classical [Ni(IPr)(η5-Cp)Cl] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). These [Ni(NHC)(η5-Cp)Cl] precatalysts were employed in the Suzuki and Kumada cross-coupling of aryl chlorides and aryl bromides. Computational studies were conducted to determine steric effect and bond order analysis. Considering the attractive features of well-defined Ni-NHCs, we anticipate that this class of bulky and flexible Ni-NHC catalysts will find broad application in organic synthesis and catalysis.
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Affiliation(s)
- Md Mahbubur Rahman
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Qun Zhao
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Guangrong Meng
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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33
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Madron du Vigné A, Cramer N. Chiral Cyclic Alkyl Amino Carbene (CAAC) Transition-Metal Complexes: Synthesis, Structural Analysis, and Evaluation in Asymmetric Catalysis. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Adrien Madron du Vigné
- Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, BCH 4305, 1015 Lausanne, Switzerland
| | - Nicolai Cramer
- Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), SB-ISIC, BCH 4305, 1015 Lausanne, Switzerland
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34
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Buzsáki D, Nyulászi L, Pietschnig R, Gudat D, Kelemen Z. Bending Ferrocenes with Low Coordinated Bridging Units: The Investigation of Carbenes and Their Analogues with a Ferrocenophane Backbone. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dániel Buzsáki
- Department of Inorganic and Analytical Chemistry, and ELKH-BME Computation Driven Chemistry Research Group, Budapest University of Technology and Economics, Műegyetem rkp 3, H-1111 Budapest, Hungary
| | - László Nyulászi
- Department of Inorganic and Analytical Chemistry, and ELKH-BME Computation Driven Chemistry Research Group, Budapest University of Technology and Economics, Műegyetem rkp 3, H-1111 Budapest, Hungary
| | - Rudolf Pietschnig
- Institut für Chemie und CINSaT, Universität Kassel, Heinrich Plett-Straße 40, 34132 Kassel, Germany
| | - Dietrich Gudat
- Institut für Anorganische Chemie, University of Stuttgart, Pfaffenwaldring 55, 70550 Stuttgart, Germany
| | - Zsolt Kelemen
- Department of Inorganic and Analytical Chemistry, and ELKH-BME Computation Driven Chemistry Research Group, Budapest University of Technology and Economics, Műegyetem rkp 3, H-1111 Budapest, Hungary
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35
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Breitwieser K, Bahmann H, Weiss R, Munz D. Gauging Radical Stabilization with Carbenes. Angew Chem Int Ed Engl 2022; 61:e202206390. [PMID: 35796423 PMCID: PMC9545232 DOI: 10.1002/anie.202206390] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Indexed: 11/29/2022]
Abstract
Carbenes, including N‐heterocyclic carbene (NHC) ligands, are used extensively to stabilize open‐shell transition metal complexes and organic radicals. Yet, it remains unknown, which carbene stabilizes a radical well and, thus, how to design radical‐stabilizing C‐donor ligands. With the large variety of C‐donor ligands experimentally investigated and their electronic properties established, we report herein their radical‐stabilizing effect. We show that radical stabilization can be understood by a captodative frontier orbital description involving π‐donation to‐ and π‐donation from the carbenes. This picture sheds a new perspective on NHC chemistry, where π‐donor effects usually are assumed to be negligible. Further, it allows for the intuitive prediction of the thermodynamic stability of covalent radicals of main group‐ and transition metal carbene complexes, and the quantification of redox non‐innocence.
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Affiliation(s)
- Kevin Breitwieser
- Coordination Chemistry Saarland University Campus C4.1 66123 Saarbrücken Germany
| | - Hilke Bahmann
- Physical and Theoretical Chemistry Saarland University Campus B2.2 66123 Saarbrücken Germany
| | - Robert Weiss
- Organische Chemie Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg Henkestr. 42 91054 Erlangen Germany
| | - Dominik Munz
- Coordination Chemistry Saarland University Campus C4.1 66123 Saarbrücken Germany
- Inorganic and General Chemistry Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
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36
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Volk J, Heinz M, Leibold M, Bruhn C, Bens T, Sarkar B, Holthausen MC, Siemeling U. A crystalline cyclic (alkyl)(amino)carbene with a 1,1'-ferrocenylene backbone. Chem Commun (Camb) 2022; 58:10396-10399. [PMID: 36039867 DOI: 10.1039/d2cc03871d] [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
Cyclic (alkyl)(amino)carbenes with a 1,1'-ferrocenylene backbone (fcCAACs) are established as an original family by the preparation of a crystalline congener. The Ccarbene bond angle is unprecedentedly wide for a CAAC, causing an exceptionally pronounced ambiphilicity. The redox-active backbone opens the door to unconventional metalloradicals and oligoradicals.
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Affiliation(s)
- Julia Volk
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany.
| | - Myron Heinz
- Institut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Michael Leibold
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany.
| | - Clemens Bruhn
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany.
| | - Tobias Bens
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 50659 Stuttgart, Germany
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 50659 Stuttgart, Germany
| | - Max C Holthausen
- Institut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Ulrich Siemeling
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany.
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37
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Philipp MSM, Bertermann R, Radius U. N-heterocyclic carbene and cyclic (alkyl)(amino)carbene adducts of plumbanes and plumbylenes. Dalton Trans 2022; 51:13488-13498. [PMID: 35997066 DOI: 10.1039/d2dt02462d] [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
Lewis-acid/base adducts of N-heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene cAACMe (1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) with selected lead(II) and lead(IV) compounds are presented. The reaction of the NHCs Me2ImMe (1,3,4,5-tetramethyl-imidazolin-2-ylidene), iPr2ImMe (1,3-di-isopropyl-4,5-dimethyl-imidazolin-2-ylidene), Dipp2Im (1,3-bis-(2,6-di-isopropylphenyl)-imidazolin-2-ylidene) and cAACMe (1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) with PbI2 yielded the NHC-containing plumbylenes NHC·PbI2 (NHC = Me2ImMe (1), iPr2ImMe (2), Dipp2Im (3) and cAACMe·PbI2 (4)). Using the Pb(IV) compound PbCl2Ph2, the plumbane adducts NHC·PbCl2Ph2 (NHC = Me2ImMe (5), iPr2ImMe (6), Dipp2Im (7)) and cAACMe·PbCl2Ph2 (8)) were isolated in high yields. Reduction of the lead(IV) adducts 5 and 6 with excess KC8 afforded the diaryl substituted plumbylenes Me2ImMe·PbPh2 (9) and iPr2ImMe·PbPh2 (10), which are stable in the solid state but decompose in solution.
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Affiliation(s)
- Michael S M Philipp
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Rüdiger Bertermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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38
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Philipp MSM, Bertermann R, Radius U. N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Germanium(IV) and Tin(IV) Chlorides and Organyl Chlorides. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Michael S. M. Philipp
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg Inorganic Chemistry GERMANY
| | - Rüdiger Bertermann
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg Inorganic Chemistry GERMANY
| | - Udo Radius
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg Institut für Anorganische Chemie Am Hubland 97074 Würzburg GERMANY
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39
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Burnett S, de Vere-Tucker M, Davitt M, Cordes DB, Slawin AMZ, Ferns R, van Mourik T, Stasch A. Magnesium Complexes with Isomeric Pyrazol‐4‐ylidene and Imidazol‐2‐ylidene Ligands. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Andreas Stasch
- University of St Andrews School of Chemistry North Haugh KY169ST St Andrews UNITED KINGDOM
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40
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de la Fuente-Olvera AA, Ruiz-Mendoza FJ, Vasquez-Perez JM, Melendez-Rodriguez M, Alvarez-Hernandez A, Salazar-Pereda V, Mendoza-Espinosa D. <p class="Title1"><span lang="DE">Rhodium(I) complexes bearing hydroxyl‐functionalized 1,2,3‐triazolylidenes and their catalytic application <o:p></o:p></span></p>. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | | | | | | | | | - Daniel Mendoza-Espinosa
- Universidad Autonoma del Estado de Hidalgo Chemsitry Carretera Pachuca-TulancingoKm 4.5Mineral de la Reforma 42090 Mineral de la Reforma MEXICO
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41
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Naskar R, Sinhababu S, Majumder A, Maity R. Synthesis of Pd
II
Triazolylidene Complexes via an Unusual C
sp2
‐C
sp2
Decoupling Reaction: Applications in α‐Arylation of Amide and Suzuki‐Miyaura Coupling Reactions. ChemistrySelect 2022. [DOI: 10.1002/slct.202201615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Rajat Naskar
- Department of Chemistry University of Calcutta 92-APC Road Kolkata 700009 India
| | | | - Adhir Majumder
- Department of Chemistry University of Calcutta 92-APC Road Kolkata 700009 India
| | - Ramananda Maity
- Department of Chemistry University of Calcutta 92-APC Road Kolkata 700009 India
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42
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Breitwieser K, Bahmann H, Weiss R, Munz D. Gauging Radical Stabilization with Carbenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kevin Breitwieser
- Saarland University: Universitat des Saarlandes Coordination Chemistry GERMANY
| | - Hilke Bahmann
- Saarland University: Universitat des Saarlandes Theoretical Chemistry GERMANY
| | - Robert Weiss
- FAU Erlangen Nuremberg: Friedrich-Alexander-Universitat Erlangen-Nurnberg Organic Chemistry GERMANY
| | - Dominik Munz
- Universitat des Saarlandes Inorganic Chemistry: Coordination Chemistry Campus C 4.1 66123 Saarbrücken GERMANY
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43
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Phosphorus stabilization of the carbene function in P-analogues of non-cyclic carbenes, N-heterocyclic carbenes and cyclic(alkyl)-(amino)carbenes − an assessment on basis of geometry, 13C, 31P chemical shifts and the anisotropy effects of the carbene electron deficient centres. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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44
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Seed JA, Vondung L, Barton F, Wooles AJ, Lu E, Gregson M, Adams RW, Liddle ST. A Series of Rare‐Earth Mesoionic Carbene Complexes. Chemistry 2022; 28:e202200761. [DOI: 10.1002/chem.202200761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Indexed: 11/05/2022]
Affiliation(s)
- John A. Seed
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Lisa Vondung
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Franky Barton
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Ashley J. Wooles
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Erli Lu
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Matthew Gregson
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Ralph W. Adams
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Stephen T. Liddle
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
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45
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Mukherjee N, Mondal B, Saha TN, Maity R. Palladium, Iridium and Rhodium Complexes Bearing Chiral N‐Heterocyclic Carbene Ligands Applied in Asymmetric Catalysis. Appl Organomet Chem 2022. [DOI: 10.1002/aoc.6794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Bhaskar Mondal
- Department of Chemistry University of Calcutta Kolkata India
| | - Tarak Nath Saha
- Department of Chemistry University of Calcutta Kolkata India
| | - Ramananda Maity
- Department of Chemistry University of Calcutta Kolkata India
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Gimferrer M, Danés S, Vos E, Yildiz CB, Corral I, Jana A, Salvador P, Andrada DM. The oxidation state in low-valent beryllium and magnesium compounds. Chem Sci 2022; 13:6583-6591. [PMID: 35756523 PMCID: PMC9172369 DOI: 10.1039/d2sc01401g] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/07/2022] [Indexed: 01/24/2023] Open
Abstract
Low-valent group 2 (E = Be and Mg) stabilized compounds have been long synthetically pursued. Here we discuss the electronic structure of a series of Lewis base-stabilized Be and Mg compounds. Despite the accepted zero(0) oxidation state nature of the group 2 elements of some recent experimentally accomplished species, the analysis of multireference wavefunctions provides compelling evidence for a strong diradical character with an oxidation state of +2. Thus, we elaborate on the distinction between a description as a donor-acceptor interaction L(0) ⇆ E(0) ⇄ L(0) and the internally oxidized situation, better interpreted as a diradical L(-1) → E(+2) ← L(-1) species. The experimentally accomplished examples rely on the strengthened bonds by increasing the π-acidity of the ligand; avoiding this interaction could lead to an unprecedented low-oxidation state.
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Affiliation(s)
- Martí Gimferrer
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Gironac/M. Aurelia Capmany 6917003GironaSpain
| | - Sergi Danés
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Gironac/M. Aurelia Capmany 6917003GironaSpain,General and Inorganic Chemistry Department, University of Saarland, Campus C4.166123 SaarbrueckenGermany
| | - Eva Vos
- Departamento de Química, Universidad Autónoma de Madridc/Francisco Tomás y Valiente 728049 Cantoblanco MadridSpain
| | - Cem B. Yildiz
- Department of Medicinal and Aromatic Plants, Aksaray UniversityHacilar harmani 268100 AksarayTurkey
| | - Inés Corral
- Departamento de Química, Universidad Autónoma de Madridc/Francisco Tomás y Valiente 728049 Cantoblanco MadridSpain
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, GopanpallyHyderabad-500046TelanganaIndia
| | - Pedro Salvador
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Gironac/M. Aurelia Capmany 6917003GironaSpain
| | - Diego M. Andrada
- General and Inorganic Chemistry Department, University of Saarland, Campus C4.166123 SaarbrueckenGermany
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Seed JA, Vondung L, Adams RW, Wooles AJ, Lu E, Liddle ST. Mesoionic Carbene Complexes of Uranium(IV) and Thorium(IV). Organometallics 2022; 41:1353-1363. [PMID: 36157256 PMCID: PMC9490841 DOI: 10.1021/acs.organomet.2c00120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Indexed: 11/30/2022]
Abstract
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We
report the synthesis and characterization of uranium(IV) and
thorium(IV) mesoionic carbene complexes [An{N(SiMe3)2}2(CH2SiMe2NSiMe3){MIC}] (An = U, 4U and Th, 4Th; MIC =
{CN(Me)C(Me)N(Me)CH}), which represent rare examples of actinide mesoionic
carbene linkages and the first example of a thorium mesoionic carbene
complex. Complexes 4U and 4Th were prepared
via a C–H activation intramolecular cyclometallation reaction
of actinide halides, with concomitant formal 1,4-proton migration
of an N-heterocyclic olefin (NHO). Quantum chemical
calculations suggest that the An–carbene bond comprises only
a σ-component, in contrast to the uranium(III) analogue [U{N(SiMe3)2}3(MIC)] (1) where computational
studies suggested that the 5f3 uranium(III) ion engages
in a weak one-electron π-backbond to the MIC. This highlights
the varying nature of actinide-MIC bonding as a function of actinide
oxidation state. In solution, 4Th exists in equilibrium
with the Th(IV) metallacycle [Th{N(SiMe3)2}2(CH2SiMe2NSiMe3)] (6Th) and free NHO (3). The thermodynamic parameters
of this equilibrium were probed using variable-temperature NMR spectroscopy
yielding an entropically favored but enthalpically endothermic process
with an overall reaction free energy of ΔG298.15K = 0.89 kcal mol–1. Energy decomposition
analysis (EDA-NOCV) of the actinide–carbon bonds in 4U and 4Th reveals that the former is enthalpically stronger
and more covalent than the latter, which accounts for the respective
stabilities of these two complexes.
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Affiliation(s)
- John A. Seed
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Lisa Vondung
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ralph W. Adams
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ashley J. Wooles
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Erli Lu
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Stephen T. Liddle
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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Thiazol-2-ylidenes as N-Heterocyclic carbene ligands with enhanced electrophilicity for transition metal catalysis. Commun Chem 2022; 5:60. [PMID: 36697942 PMCID: PMC9814509 DOI: 10.1038/s42004-022-00675-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 01/28/2023] Open
Abstract
Over the last 20 years, N-heterocyclic carbenes (NHCs) have emerged as a dominant direction in ligand development in transition metal catalysis. In particular, strong σ-donation in combination with tunable steric environment make NHCs to be among the most common ligands used for C-C and C-heteroatom bond formation. Herein, we report the study on steric and electronic properties of thiazol-2-ylidenes. We demonstrate that the thiazole heterocycle and enhanced π-electrophilicity result in a class of highly active carbene ligands for electrophilic cyclization reactions to form valuable oxazoline heterocycles. The evaluation of steric, electron-donating and π-accepting properties as well as structural characterization and coordination chemistry is presented. This mode of catalysis can be applied to late-stage drug functionalization to furnish attractive building blocks for medicinal chemistry. Considering the key role of N-heterocyclic ligands, we anticipate that N-aryl thiazol-2-ylidenes will be of broad interest as ligands in modern chemical synthesis.
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