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Hussein AA, Ariffin A. Remote Steric and Electronic Effects of N-Heterocyclic Carbene Ligands on Alkene Reactivity and Regioselectivity toward Hydrocupration Reactions: The Role of Expanded-Ring N-Heterocyclic Carbenes. J Org Chem 2023; 88:13009-13021. [PMID: 37649423 DOI: 10.1021/acs.joc.3c01121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
The remote groups in N-heterocyclic carbene (NHC) ligands have a significant influence on metal-catalyzed reactions. We examine how remote bulkiness, electronic groups, and expanded-ring NHCs (ER-NHCs) influence alkene reactivity and regioselectivity toward hydrocupration using density functional theory calculations. The impact of remote steric bulkiness on the Cu-H insertion rate is analyzed, revealing a strong correlation between the steric substituent constant and rate ratio, where a bulky group increases the rate due to reduced steric effects in the transition state (TS). The steric properties of the examined catalysts (with a remote group R2 = CPh3, CHPh2, CH2Ph, CH3, and H) and their corresponding TSs are found to be modulated greatly by the remote steric substitution group and the ring size of the NHC ligand. Enhanced bulkiness enhances the nucleophilic Cu-H moiety. The remote electronic groups have a smaller impact on insertion barrier compared to that of steric hindrance. Furthermore, ER-NHC exploration indicates that NHCs with over five-membered rings have a significantly negative influence on the reaction rate. Finally, with a highly bulky group (R2 = CPh3), anti-Markovnikov insertion preference is attributed to high interaction energy and improved steric properties. Overall, our findings here provide valuable insights for the development of a more effective catalyst in metal-catalyzed reactions.
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Affiliation(s)
- Aqeel A Hussein
- Department of Medical Laboratory Science, College of Science, Komar University of Science and Technology, Sulaymaniyah, Kurdistan Region 46001, Iraq
- Department of Biology, College of Science, Al-Qasim Green University, Al-Qassim, Babylon 51013, Iraq
| | - Azhar Ariffin
- Department of Chemistry, Faculty of Science, University Malaya, Kuala Lumpur 50603, Malaysia
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2
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Kim H, Lee E. Ambiphilic singlet carbenes: Electron donors and acceptors. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hyunho Kim
- Department of Chemistry Pohang University of Science and Technology Pohang Republic of Korea
| | - Eunsung Lee
- Department of Chemistry Pohang University of Science and Technology Pohang Republic of Korea
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3
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Ma Y, Ali HS, Hussein AA. A mechanistic study on the gold(i)-catalyzed cyclization of propargylic amide: revealing the impact of expanded-ring N-heterocyclic carbenes. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01617b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density functional theory (DFT) was applied to understand the mechanistic pathway of the gold(i)-catalyzed cyclization of propargylic amide, and to reveal the impact of expanded-ring N-heterocyclic carbenes.
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Affiliation(s)
- Yumiao Ma
- BSJ Institute, Haidian, Beijing, 100084, People's Republic of China
- Hangzhou Yanqu Information Technology Co., Ltd., Xixi Legu Creative Pioneering Park, No. 712 Wen'er West Road, Xihu District, Hangzhou City, Zhejiang Province, 310003, People's Republic of China
| | - Hafiz Saqib Ali
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Rd, Kings Buildings, EH9 3FJ Edinburgh, UK
| | - Aqeel A. Hussein
- Department of Pharmacy, College of Medicine, Komar University of Science and Technology, Sulaymaniyah, Kurdistan Region, Iraq
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4
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Shilpa T, Neetha M, Anilkumar G. Recent Trends and Prospects in the Copper‐Catalysed “on Water” Reactions. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202001407] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Thomas Shilpa
- School of Chemical Sciences Mahatma Gandhi University Priyadarsini Hills Kottayam Kerala INDIA 686560
| | - Mohan Neetha
- School of Chemical Sciences Mahatma Gandhi University Priyadarsini Hills Kottayam Kerala INDIA 686560
| | - Gopinathan Anilkumar
- School of Chemical Sciences Mahatma Gandhi University Priyadarsini Hills Kottayam Kerala INDIA 686560
- Advanced Molecular materials Research centre (AMMRC) Mahatma Gandhi University Priyadarsini Hills P O Kottayam Kerala INDIA 686560
- Institute for Integrated programmes and Research in Basic Sciences (IIRBS) Mahatma Gandhi University Priyadarsini Hills P O Kottayam Kerala INDIA 686560
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5
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Cervantes‐Reyes A, Rominger F, Hashmi ASK. Sterically Demanding Ag I and Cu I N-Heterocyclic Carbene Complexes: Synthesis, Structures, Steric Parameters, and Catalytic Activity. Chemistry 2020; 26:5530-5540. [PMID: 32104933 PMCID: PMC7216994 DOI: 10.1002/chem.202000600] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/27/2020] [Indexed: 12/13/2022]
Abstract
The synthesis and full characterization of new air-stable AgI and CuI complexes bearing structurally bulky expanded-ring N-heterocyclic carbene (erNHC) ligands is presented. The condensation of protonated NHC salts with Ag2 O afforded a collection of AgI complexes, and their first use as ligand transfer reagents led to novel isostructural CuI or AuI complexes. In situ deprotonation of the NHC salts in the presence of a copper(I) source, provides a library of new CuI complexes. The solid-state structures feature large N-CNHC -N angles (118-128°) and almost identical angles between the aryl groups on the nitrogen atoms and the plane of the N-C-N unit of the carbene (i.e. torsion angles close to 0°). Among the steric parameters, the percent buried volume (%Vbur ) values span easily in the 50-57 % range, and that one of (9-Dipp)CuBr complex (%Vbur =57.5) overcomes to other known erNHC-metal complexes reported to date. Preliminary catalytic experiments in the copper-catalyzed coupling between N-tosylhydrazone and phenylacetylene, afforded 76-93 % product at the 0.5-2.5 mol % catalyst loading, proving the stability of CuI erNHC complexes at elevated temperatures (100 °C).
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Affiliation(s)
| | - Frank Rominger
- Organisch-Chemisches InstitutHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
| | - A. Stephen K. Hashmi
- Organisch-Chemisches InstitutHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
- Chemistry DepartmentFaculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia
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6
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Cervantes‐Reyes A, Rominger F, Rudolph M, Hashmi ASK. Gold(I) Complexes Stabilized by Nine- and Ten-Membered N-Heterocyclic Carbene Ligands. Chemistry 2019; 25:11745-11757. [PMID: 31310385 PMCID: PMC6852534 DOI: 10.1002/chem.201902458] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Indexed: 02/02/2023]
Abstract
Nine- and ten-membered N-heterocyclic carbene (NHC) ligands have been developed and for the first time their gold(I) complexes were synthesized. The protonated NHC pro-ligands 2 a-h were prepared by the reaction of readily available N,N'-diarylformamidines with bis-electrophilic building blocks, followed by anion exchange. In situ deprotonation of the tetrafluoroborates 2 a-h with tBuOK in the presence of AuCl(SMe2 ) provided fast access to NHC-gold(I) complexes 3-10. These new NHC-gold(I) complexes show very good catalytic activity in a cycloisomerization reaction (0.1 mol % catalyst loading, up to 100 % conversion) and their solid-state structures reveal high steric hindrance around the metal atom (%Vbur up to 53.0) which is caused by their expanded-ring architecture.
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Affiliation(s)
| | - Frank Rominger
- Organisch-Chemisches InstitutHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Matthias Rudolph
- Organisch-Chemisches InstitutHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
| | - A. Stephen K. Hashmi
- Organisch-Chemisches InstitutHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
- Chemistry DepartmentFaculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia
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7
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Sampford KR, Carden JL, Kidner EB, Berry A, Cavell KJ, Murphy DM, Kariuki BM, Newman PD. Twisting the arm: structural constraints in bicyclic expanded-ring N-heterocyclic carbenes. Dalton Trans 2019; 48:1850-1858. [PMID: 30652174 DOI: 10.1039/c8dt04462g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A series of diaryl, mono-aryl/alkyl and dialkyl mono- and bicyclic expanded-ring N-heterocyclic carbenes (ER-NHCs) have been prepared and their complexation to Au(i) investigated through the structural analysis of fifteen Au(NHC)X and/or [Au(NHC)2]X complexes. The substituted diaryl 7-NHCs are the most sterically encumbered with large buried volume (%VB) values of 40-50% with the less flexible six-membered analogues having %VB values at least 5% smaller. Although the bicyclic systems containing fused 6- and 7-membered rings (6,7-NHCs) are constrained with relatively acute NCN bond angles, they have the largest %VB values of the dialkyl derivatives reported here, a feature related to the fixed conformation of the heterocyclic rings and the compressional effect of a pre-set methyl substituent.
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Affiliation(s)
| | - Jamie L Carden
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | - Edward B Kidner
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | - Abigail Berry
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | | | - Damien M Murphy
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | | | - Paul D Newman
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK and Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK.
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8
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Chauhan RS, Oza D, Yadav S, Dash C, Slawin AMZ, Shivran N. Copper complexes of arylselenolate-based ligands: synthesis and catalytic activity in azide–alkyne cycloaddition reactions. NEW J CHEM 2019. [DOI: 10.1039/c8nj04602f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Arylselenolate-based copper complexes have been synthesized and used as pre-catalysts for azide-alkyne cycloaddition reactions.
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Affiliation(s)
- Rohit Singh Chauhan
- Department of Chemistry, K. J. Somaiya College of Science and Commerce
- Mumbai-400 078
- India
| | - Dhvani Oza
- Department of Chemistry, K. J. Somaiya College of Science and Commerce
- Mumbai-400 078
- India
| | - Seema Yadav
- Department of Chemistry, Central University of Rajasthan
- Ajmer-305817
- India
| | - Chandrakanta Dash
- Department of Chemistry, Central University of Rajasthan
- Ajmer-305817
- India
| | | | - Neelam Shivran
- Department of Chemistry, Indian Institute of Science Education and Research
- Pune-411008
- India
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9
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Hall JW, Unson DML, Brunel P, Collins LR, Cybulski MK, Mahon MF, Whittlesey MK. Copper-NHC-Mediated Semihydrogenation and Hydroboration of Alkynes: Enhanced Catalytic Activity Using Ring-Expanded Carbenes. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00467] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jonathan W. Hall
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
| | - Darcy M. L. Unson
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
| | - Paul Brunel
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
| | - Lee R. Collins
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
| | - Mateusz K. Cybulski
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
| | - Michael K. Whittlesey
- Department of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, United Kingdom
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10
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Misztalewska-Turkowicz I, Markiewicz K, Michalak M, Wilczewska A. NHC-copper complexes immobilized on magnetic nanoparticles: Synthesis and catalytic activity in the CuAAC reactions. J Catal 2018. [DOI: 10.1016/j.jcat.2018.03.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Sebest F, Dunsford JJ, Adams M, Pivot J, Newman PD, Díez‐González S. Ring-Expanded N-Heterocyclic Carbenes for Copper-Mediated Azide-Alkyne Click Cycloaddition Reactions. ChemCatChem 2018; 10:2041-2045. [PMID: 29861792 PMCID: PMC5969269 DOI: 10.1002/cctc.201701992] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Indexed: 11/08/2022]
Abstract
A series of well-defined copper(I) complexes bearing ring-expanded N-heterocyclic carbene (NHC) ligands has been applied to the azide-alkyne cycloaddition reaction. The obtained results notably showed that the six-membered NHC ligands outperform well-established five-membered ones. [CuI(Mes-6)] displayed a remarkable catalytic activity while respecting the strict criteria for click reactions.
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Affiliation(s)
- Filip Sebest
- Department of ChemistryImperial College LondonExhibition Road, South KensingtonLondonSW7 2AZUK
| | | | - Matthew Adams
- Department of ChemistryImperial College LondonExhibition Road, South KensingtonLondonSW7 2AZUK
| | - Jeremy Pivot
- Department of ChemistryImperial College LondonExhibition Road, South KensingtonLondonSW7 2AZUK
| | | | - Silvia Díez‐González
- Department of ChemistryImperial College LondonExhibition Road, South KensingtonLondonSW7 2AZUK
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12
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New C 2 -symmetric six-membered carbene ligands incorporating two hydroxyl groups for palladium-catalyzed deprotonative-cross-coupling processes (DCCP) of sp 3 C–H bonds in diarylmethanes. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.09.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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13
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Karaca EÖ, Akkoç M, Öz E, Altin S, Dorcet V, Roisnel T, Gürbüz N, Çelik Ö, Bayri A, Bruneau C, Yaşar S, Özdemir I. Ring-expanded iridium and rhodiumN-heterocyclic carbene complexes: a comparative DFT study of heterocycle ring size and metal center diversity. J COORD CHEM 2017. [DOI: 10.1080/00958972.2017.1287906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- E. Ö. Karaca
- Department of Chemistry, İnönü University, Malatya, Turkey
| | - M. Akkoç
- Department of Chemistry, İnönü University, Malatya, Turkey
| | - E. Öz
- Department of Physics, İnönü University, Malatya, Turkey
| | - S. Altin
- Department of Physics, İnönü University, Malatya, Turkey
| | - V. Dorcet
- Université de Rennes, UMR 6226: CNRS Sciences Chimiques de Rennes, Rennes, France
| | - T. Roisnel
- Université de Rennes, UMR 6226: CNRS Sciences Chimiques de Rennes, Rennes, France
| | - N. Gürbüz
- Department of Chemistry, İnönü University, Malatya, Turkey
| | - Ö. Çelik
- Department of Physics, Dicle University, Diyarbakır, Turkey
| | - A. Bayri
- Department of Physics, İnönü University, Malatya, Turkey
| | - C. Bruneau
- Université de Rennes, UMR 6226: CNRS Sciences Chimiques de Rennes, Rennes, France
| | - S. Yaşar
- Department of Chemistry, İnönü University, Malatya, Turkey
| | - I. Özdemir
- Department of Chemistry, İnönü University, Malatya, Turkey
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14
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Shi S, Collins LR, Mahon MF, Djurovich PI, Thompson ME, Whittlesey MK. Synthesis and characterization of phosphorescent two-coordinate copper(i) complexes bearing diamidocarbene ligands. Dalton Trans 2017; 46:745-752. [DOI: 10.1039/c6dt04016k] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
[(DAC)2Cu][BF4] (1) shows a high photoluminescence quantum efficiency (ΦPL) in the solid state and in solution under both N2 and O2.
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Affiliation(s)
- Shuyang Shi
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
| | | | - Mary F. Mahon
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
| | | | - Mark E. Thompson
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
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15
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Collins LR, Rajabi NA, Macgregor SA, Mahon MF, Whittlesey MK. Experimental and Computational Studies of the Copper Borate Complexes [(NHC)Cu(HBEt3)] and [(NHC)Cu(HB(C6F5)3)]. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lee R. Collins
- Department of Chemistry; University of Bath; Claverton Down Bath BA2 7AY UK
| | - Nasir A. Rajabi
- Institute of Chemical Sciences; Heriot Watt University; Edinburgh EH14 4AS UK
| | - Stuart A. Macgregor
- Institute of Chemical Sciences; Heriot Watt University; Edinburgh EH14 4AS UK
| | - Mary F. Mahon
- Department of Chemistry; University of Bath; Claverton Down Bath BA2 7AY UK
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16
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Collins LR, Rajabi NA, Macgregor SA, Mahon MF, Whittlesey MK. Experimental and Computational Studies of the Copper Borate Complexes [(NHC)Cu(HBEt3)] and [(NHC)Cu(HB(C6F5)3)]. Angew Chem Int Ed Engl 2016; 55:15539-15543. [DOI: 10.1002/anie.201608081] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/19/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Lee R. Collins
- Department of Chemistry; University of Bath; Claverton Down Bath BA2 7AY UK
| | - Nasir A. Rajabi
- Institute of Chemical Sciences; Heriot Watt University; Edinburgh EH14 4AS UK
| | - Stuart A. Macgregor
- Institute of Chemical Sciences; Heriot Watt University; Edinburgh EH14 4AS UK
| | - Mary F. Mahon
- Department of Chemistry; University of Bath; Claverton Down Bath BA2 7AY UK
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17
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Wang C, Ikhlef D, Kahlal S, Saillard JY, Astruc D. Metal-catalyzed azide-alkyne “click” reactions: Mechanistic overview and recent trends. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.02.010] [Citation(s) in RCA: 219] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Topchiy MA, Dzhevakov PB, Rubina MS, Morozov OS, Asachenko AF, Nechaev MS. Solvent-Free Buchwald-Hartwig (Hetero)arylation of Anilines, Diarylamines, and Dialkylamines Mediated by Expanded-Ring N-Heterocyclic Carbene Palladium Complexes. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501616] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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19
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Hohloch S, Suntrup L, Sarkar B. Exploring potential cooperative effects in dicopper(i)-di-mesoionic carbene complexes: applications in click catalysis. Inorg Chem Front 2016. [DOI: 10.1039/c5qi00163c] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dicopper(i) dimesoionic carbene complexes are active catalysts for the azide–alkyne cycloaddition reaction and are more active than their mononuclear counterparts.
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Affiliation(s)
- Stephan Hohloch
- Institut für Chemie und Biochemie
- Freie Universität Berlin
- Berlin
- Germany
| | - Lisa Suntrup
- Institut für Chemie und Biochemie
- Freie Universität Berlin
- Berlin
- Germany
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie
- Freie Universität Berlin
- Berlin
- Germany
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20
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Collins LR, Riddlestone IM, Mahon MF, Whittlesey MK. A Comparison of the Stability and Reactivity of Diamido‐ and Diaminocarbene Copper Alkoxide and Hydride Complexes. Chemistry 2015; 21:14075-84. [DOI: 10.1002/chem.201502476] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Indexed: 02/05/2023]
Affiliation(s)
- Lee R. Collins
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Ian M. Riddlestone
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Michael K. Whittlesey
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (UK), Fax: (+44) 1225‐386‐231
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21
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Petrov AR, Derheim A, Oetzel J, Leibold M, Bruhn C, Scheerer S, Oßwald S, Winter RF, Siemeling U. A Stable Planar-Chiral N-Heterocyclic Carbene with a 1,1'-Ferrocenediyl Backbone. Inorg Chem 2015; 54:6657-70. [PMID: 26098133 DOI: 10.1021/acs.inorgchem.5b01064] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper focuses on the stable, ferrocene-based N-heterocyclic carbene (NHC) rac-[Fe{(η(5)-t-BuC5H3)NpN}2C:] (A'-Np, Np = neopentyl), which is planar-chiral due to the two tert-butyl substituents in 3,3'-positions. A'-Np was synthesized in nine steps starting from 1,1'-di-tert-butylferrocene (1), the first step being its 3,3'-dilithiation to afford rac-[Fe(η(5)-t-BuC5H3Li)2] (rac-fc'Li2, 2). The structures of rac-fc'(SiMe3)2 (3), rac-fc'Br2 (4), rac-fc'(N3)2 (5), and the immediate carbene precursor [A'-NpH]BF4 were determined by single-crystal X-ray diffraction (XRD). The chemical properties of A'-Np were found to be very similar to those of its tert-butyl-free congener A-Np, both being ambiphilic NHCs with rather high calculated HOMO energies (ca. -4.0 eV) and low singlet-triplet gaps (ca. 35 kcal/mol). A Tolman electronic parameter value of 2050 cm(-1) was derived from IR data of cis-[RhCl(A'-Np)(CO)2], indicating the high donicity of A'-Np as a ligand. Consistent with its ambiphilic nature, A'-Np was found to react readily with carbon monoxide, affording the betainic enolate (A'-Np)2CO as four stereoisomers, viz. (RpRp-A'-Np)═C(O(-))(RpRp-A'-Np(+)), (SpSp-A'-Np)═C(O(-))(SpSp-A'-Np(+)), (RpRp-A'-Np)═C(O(-))(SpSp-A'-Np(+)), and (SpSp-A'-Np)═C(O(-))(RpRp-A'-Np(+)). The former two isomers were structurally characterized as a racemic compound by single-crystal XRD. A'-Np was found to react swiftly with dichloromethane, affording the addition product A'-NpH-CHCl2 in a reaction that is unprecedented for diaminocarbenes. A-NpH-CHCl2 was obtained analogously. Both compounds were structurally characterized by single-crystal XRD. An electrochemical investigation of A'-Np by cyclic and square wave voltammetry revealed a reversible oxidation of the carbene at a half-wave potential of -0.310 vs ferrocene/ferrocenium (THF/NBu4PF6). The electrochemical data previously published for A-Np were identified to be incorrect, since unnoticed hydrolysis of the NHC had taken place, affording A-Np(H2O). The hydrolysis products of A-Np and A'-Np were found to be reversibly oxidized at half-wave potentials of -0.418 and -0.437 V, respectively.
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Affiliation(s)
- Alex R Petrov
- †Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Anatoli Derheim
- †Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Jan Oetzel
- †Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Michael Leibold
- †Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Clemens Bruhn
- †Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Stefan Scheerer
- ‡Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Steffen Oßwald
- ‡Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Rainer F Winter
- ‡Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Ulrich Siemeling
- †Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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22
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Collins LR, Hierlmeier G, Mahon MF, Riddlestone IM, Whittlesey MK. Unexpected Migratory Insertion Reactions of M(alkyl)
2
(M=Zn, Cd) and Diamidocarbenes. Chemistry 2015; 21:3215-8. [DOI: 10.1002/chem.201406406] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Lee R. Collins
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Gabriele Hierlmeier
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Ian M. Riddlestone
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (UK), Fax: (+44) 1225‐386‐231
| | - Michael K. Whittlesey
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (UK), Fax: (+44) 1225‐386‐231
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23
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Yang L, Zhang X, Mao P, Xiao Y, Bian H, Yuan J, Mai W, Qu L. NCN pincer palladium complexes based on 1,3-dipicolyl-3,4,5,6-tetrahydropyrimidin-2-ylidenes: synthesis, characterization and catalytic activities. RSC Adv 2015. [DOI: 10.1039/c5ra01706h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
NCN pincer six-membered NHC palladium complexes were synthesized, characterized and used in Heck reaction of aryl bromides with olefines.
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Affiliation(s)
- Liangru Yang
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Xinchi Zhang
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Pu Mao
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Yongmei Xiao
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Huanyu Bian
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Jinwei Yuan
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Wenpeng Mai
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Lingbo Qu
- School of Chemistry and Chemical Engineering
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
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