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Kleinhans G, Karhu AJ, Boddaert H, Tanweer S, Wunderlin D, Bezuidenhout DI. LNL-Carbazole Pincer Ligand: More than the Sum of Its Parts. Chem Rev 2023. [PMID: 37351619 DOI: 10.1021/acs.chemrev.3c00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
The utility of carbazole in photo-, electro-, and medicinal applications has ensured its widespread use also as the backbone in tridentate pincer ligands. In this review, the aim is to identify and illustrate the key features of the LNL-carbazolide binding to transition metal centers (with L = flanking donor moieties, e.g., C, N, P, and O-groups) in a systematic bottom-up progression to illustrate the marked benefits attainable from (i) the rigid aromatic carbazole scaffold (modulable in both the 1,8- and 3,6-positions), (ii) the significant electronic effect of central carbazole-amido binding to a metal, and the tunable sterics and electronics of both the (iii) flanking donor L-moieties and (iv) the wingtip R-groups on the L-donors, with their corresponding influence on metal coordination geometry, d-electron configuration, and resultant reactivity. Systematic implementation of the ligand design strategies not in isolation, but in a combinatorial approach, is showcased to demonstrate the potential for functional molecules that are not only modulable but also adaptable for wide-ranging applications (e.g., stereoselective (photo)catalysis, challenging small molecule activation, SET and redox applications, and even applications in chemotherapeutics) as an indication of future research efforts anticipated to stem from this versatile pincer assembly, not only for the transition metals but also for s-, p-, and f-block elements.
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Affiliation(s)
- George Kleinhans
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Aino J Karhu
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Hugo Boddaert
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Sadia Tanweer
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - David Wunderlin
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Daniela I Bezuidenhout
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
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Louw WJ, Radhakrishnan SG, Malan FP, Bezuidenhout DI. Synthesis, electronic structure and interaction of rhodium(I) and iridium(I) bisimine-acenaphthalene complexes with CO2. Polyhedron 2023. [DOI: 10.1016/j.poly.2023.116350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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3
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Moeng MM, Malan FP, Lotz S, Bezuidenhout DI. Fischer carbene complexes of cobalt(I): Synthesis and structure. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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van der Westhuizen D, Bezuidenhout DI, Munro OQ. Cancer molecular biology and strategies for the design of cytotoxic gold(I) and gold(III) complexes: a tutorial review. Dalton Trans 2021; 50:17413-17437. [PMID: 34693422 DOI: 10.1039/d1dt02783b] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This tutorial review highlights key principles underpinning the design of selected metallodrugs to target specific biological macromolecules (DNA and proteins). The review commences with a descriptive overview of the eukaryotic cell cycle and the molecular biology of cancer, particularly apoptosis, which is provided as a necessary foundation for the discovery, design, and targeting of metal-based anticancer agents. Drugs which target DNA have been highlighted and clinically approved metallodrugs discussed. A brief history of the development of mainly gold-based metallodrugs is presented prior to addressing ligand systems for stabilizing and adding functionality to bio-active gold(I) and gold(III) complexes, particularly in the burgeoning field of anticancer metallodrugs. Concepts such as multi-modal and selective cytotoxic agents are covered where necessary for selected compounds. The emerging role of carbenes as the ligand system of choice to achieve these goals for gold-based metallodrug candidates is highlighted prior to closing the review with comments on some future directions that this research field might follow. The latter section ultimately emphasizes the importance of understanding the fate of metal complexes in cells to garner key mechanistic insights.
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Affiliation(s)
- Danielle van der Westhuizen
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.
| | - Daniela I Bezuidenhout
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, University of Oulu, P. O. Box 3000, 90014 Oulu, Finland.
| | - Orde Q Munro
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.
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5
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Westhuizen D, Slabber CA, Fernandes MA, Joubert DF, Kleinhans G, Westhuizen CJ, Stander A, Munro OQ, Bezuidenhout DI. Cover Feature: A Cytotoxic Bis(1,2,3‐triazol‐5‐ylidene)carbazolide Gold(III) Complex Targets DNA by Partial Intercalation (Chem. Eur. J. 32/2021). Chemistry 2021. [DOI: 10.1002/chem.202101553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Danielle Westhuizen
- Molecular Sciences Institute School of Chemistry University of the Witwatersrand 2050 Johannesburg South Africa
| | - Cathryn A. Slabber
- Molecular Sciences Institute School of Chemistry University of the Witwatersrand 2050 Johannesburg South Africa
| | - Manuel A. Fernandes
- Molecular Sciences Institute School of Chemistry University of the Witwatersrand 2050 Johannesburg South Africa
| | - Daniël F. Joubert
- Department of Physiology University of Pretoria 0031 Pretoria South Africa
| | - George Kleinhans
- Molecular Sciences Institute School of Chemistry University of the Witwatersrand 2050 Johannesburg South Africa
- Chemistry Department University of Pretoria 0028 Pretoria South Africa
| | - C. Johan Westhuizen
- Chemistry Department University of Pretoria 0028 Pretoria South Africa
- Future Production: Chemicals Pharmaceutical Technologies Research Group Council for Scientific and Industrial Research (CSIR) 0184 Pretoria South Africa
| | - André Stander
- Department of Physiology University of Pretoria 0031 Pretoria South Africa
| | - Orde Q. Munro
- Molecular Sciences Institute School of Chemistry University of the Witwatersrand 2050 Johannesburg South Africa
| | - Daniela I. Bezuidenhout
- Molecular Sciences Institute School of Chemistry University of the Witwatersrand 2050 Johannesburg South Africa
- Laboratory of Inorganic Chemistry Environmental and Chemical Engineering University of Oulu 3000 Oulu Finland
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6
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van der Westhuizen D, Slabber CA, Fernandes MA, Joubert DF, Kleinhans G, van der Westhuizen CJ, Stander A, Munro OQ, Bezuidenhout DI. A Cytotoxic Bis(1,2,3-triazol-5-ylidene)carbazolide Gold(III) Complex Targets DNA by Partial Intercalation. Chemistry 2021; 27:8295-8307. [PMID: 33822431 PMCID: PMC8251726 DOI: 10.1002/chem.202100598] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Indexed: 12/13/2022]
Abstract
The syntheses of bis(triazolium)carbazole precursors and their corresponding coinage metal (Au, Ag) complexes are reported. For alkylated triazolium salts, di- or tetranuclear complexes with bridging ligands were isolated, while the bis(aryl) analogue afforded a bis(carbene) AuI -CNC pincer complex suitable for oxidation to the redox-stable [AuIII (CNC)Cl]+ cation. Although the ligand salt and the [AuIII (CNC)Cl]+ complex were both notably cytotoxic toward the breast cancer cell line MDA-MB-231, the AuIII complex was somewhat more selective. Electrophoresis, viscometry, UV-vis, CD and LD spectroscopy suggest the cytotoxic [AuIII (CNC)Cl]+ complex behaves as a partial DNA intercalator. In silico screening indicated that the [AuIII (CNC)Cl]+ complex can target DNA three-way junctions with good specificity, several other regular B-DNA forms, and Z-DNA. Multiple hydrophobic π-type interactions involving T and A bases appear to be important for B-form DNA binding, while phosphate O⋅⋅⋅Au interactions evidently underpin Z-DNA binding. The CNC ligand effectively stabilizes the AuIII ion, preventing reduction in the presence of glutathione. Both the redox stability and DNA affinity of the hit compound might be key factors underpinning its cytotoxicity in vitro.
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Affiliation(s)
| | - Cathryn A. Slabber
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
| | - Manuel A. Fernandes
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
| | - Daniël F. Joubert
- Department of PhysiologyUniversity of Pretoria0031PretoriaSouth Africa
| | - George Kleinhans
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
- Chemistry DepartmentUniversity of Pretoria0028PretoriaSouth Africa
| | - C. Johan van der Westhuizen
- Chemistry DepartmentUniversity of Pretoria0028PretoriaSouth Africa
- Future Production: ChemicalsPharmaceutical Technologies Research GroupCouncil for Scientific and Industrial Research (CSIR)0184PretoriaSouth Africa
| | - André Stander
- Department of PhysiologyUniversity of Pretoria0031PretoriaSouth Africa
| | - Orde Q. Munro
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
| | - Daniela I. Bezuidenhout
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
- Laboratory of Inorganic ChemistryEnvironmental and Chemical EngineeringUniversity of Oulu3000OuluFinland
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7
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Lamprecht Z, Malan FP, Lotz S, Bezuidenhout DI. Synthesis and structure of thienyl Fischer carbene complexes of Pt II for application in alkyne hydrosilylation. NEW J CHEM 2021. [DOI: 10.1039/d1nj00791b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Efficient alkyne hydrosilylation mediated by well-defined platinum(ii) bis(ethoxycarbene) complexes of the Fischer-type prepared by facile transmetallation.
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Affiliation(s)
- Zandria Lamprecht
- Department of Chemistry
- University of Pretoria
- Hatfield 0028
- South Africa
| | | | - Simon Lotz
- Department of Chemistry
- University of Pretoria
- Hatfield 0028
- South Africa
| | - Daniela I. Bezuidenhout
- Laboratory of Inorganic Chemistry
- Environmental and Chemical Engineering
- University of Oulu
- 90014 Oulu
- Finland
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8
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Tolley LC, Fernández I, Bezuidenhout DI, Guisado-Barrios G. Catalytic conversion of alkynes to α-vinyl sulfides mediated by carbene-linker-carbene (CXC) rhodium and iridium complexes. Catal Sci Technol 2021. [DOI: 10.1039/d0cy01647k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The performance of a set of mono- and bimetallic Rh(i) and Ir(i) complexes bearing carbene-linker-carbene (CXC) bis-triazolylidene ligands (with X = O, N) coordinated in a bridging or chelating fashion was evaluated in the hydrothiolation of alkynes.
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Affiliation(s)
- Lewis C. Tolley
- Molecular Sciences Institute
- School of Chemistry
- University of the Witwatersrand
- Johannesburg
- South Africa
| | - Israel Fernández
- Departamento de Química Orgánica I and Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- Madrid
- Spain
| | - Daniela I. Bezuidenhout
- Molecular Sciences Institute
- School of Chemistry
- University of the Witwatersrand
- Johannesburg
- South Africa
| | - Gregorio Guisado-Barrios
- Institute of Advance Materials (INAM)
- Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Universitat Jaume I
- 12071 Castellón
- Spain
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9
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Lamprecht Z, Malan FP, Fernández I, Lotz S, Bezuidenhout DI. Chelated Fischer carbene complexes of annulated thiophenes: synthesis, structure and electrochemistry. Dalton Trans 2020; 49:15339-15354. [PMID: 33124632 DOI: 10.1039/d0dt03298k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two (thieno[3,2-b]thiophene) and three annulated thiophenes (dithieno[2,3-b;3',2'-d]thiophene and dithieno[3,2-b;2',3'-d]thiophene) were employed as building blocks to synthesize linear or semi-circular chelated mononuclear biscarbene and dinuclear tetracarbene complexes. The electronic properties of the annulated thienylene chelated carbene complexes were investigated by cyclic voltammetry experiments and compared to non-chelated Fischer-type monocarbene complexes. Density functional theory (DFT) calculations were used to assign the redox events and to probe the extent of electron delocalisation as well as the possibility of electronic (intramolecular metal-metal) communication as a result of intervalence. The differences of these electronic properties in the conjugated chelated carbene complexes are compared to chelated carbene compounds without a linear conjugated pathway.
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Affiliation(s)
- Zandria Lamprecht
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa
| | - Frederick P Malan
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa
| | - Israel Fernández
- Departamento de Química Orgánica I and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Simon Lotz
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa
| | - Daniela I Bezuidenhout
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, University of Oulu, P. O. Box 3000, 90014 Oulu, Finland.
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10
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Lamprecht Z, Malan FP, Liles DC, Lotz S, Bezuidenhout DI. Synthesis and structure of annulated dithieno[2,3-b;3ʹ,2ʹ-d]thienyl- and ring-opened 3,3ʹ-bithienyl Fischer carbene complexes. J Organomet Chem 2020. [DOI: 10.1016/j.jorganchem.2020.121466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Mashabane TL, Ramollo GK, Kleinhans G, De Doncker S, Siangwata S, Fernandes MA, Lemmerer A, Smith GS, Bezuidenhout DI. Tunable Rh(I) Fischer carbene complexes for application in the hydroformylation of 1-octene. J Organomet Chem 2020. [DOI: 10.1016/j.jorganchem.2020.121341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Kleinhans G, Chan AKW, Leung MY, Liles DC, Fernandes MA, Yam VWW, Fernández I, Bezuidenhout DI. Synthesis and Photophysical Properties of T-Shaped Coinage-Metal Complexes. Chemistry 2020; 26:6993-6998. [PMID: 32182384 PMCID: PMC7317956 DOI: 10.1002/chem.202000726] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Indexed: 11/28/2022]
Abstract
The photophysical properties of a series of T‐shaped coinage d10 metal complexes, supported by a bis(mesoionic carbene)carbazolide (CNC) pincer ligand, are explored. The series includes a rare new example of a tridentate T‐shaped AgI complex. Post‐complexation modification of the AuI complex provides access to a linear cationic AuI complex following ligand alkylation, or the first example of a cationic square planar AuIII−F complex from electrophilic attack on the metal centre. Emissions ranging from blue (CuI) to orange (AgI) are obtained, with variable contributions of thermally‐dependent fluorescence and phosphorescence to the observed photoluminescence. Green emissions are observed for all three gold complexes (neutral T‐shaped AuI, cationic linear AuI and square planar cationic AuIII). The higher quantum yield and longer decay lifetime of the linear gold(I) complex are indicative of increased phosphorescence contribution.
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Affiliation(s)
- George Kleinhans
- Chemistry Department, University of Pretoria, Private X20, Hatfield, 0028, South Africa.,Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, 2050, South Africa
| | - Alan K-W Chan
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Ming-Yi Leung
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - David C Liles
- Chemistry Department, University of Pretoria, Private X20, Hatfield, 0028, South Africa
| | - Manuel A Fernandes
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, 2050, South Africa
| | - Vivian W-W Yam
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Israel Fernández
- Departamento de Química Orgánica I, Centro de Innovación en Química Avanzado (ORFEO-CINQA) and, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Daniela I Bezuidenhout
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, 2050, South Africa.,Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, University of Oulu, P. O. Box 3000, 90014, Oulu, Finland
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Ramollo GK, Strydom I, Fernandes MA, Lemmerer A, Ojwach SO, van Wyk JL, Bezuidenhout DI. Fischer Carbene Complexes of Iridium(I) for Application in Catalytic Transfer Hydrogenation. Inorg Chem 2020; 59:4810-4815. [PMID: 32212623 PMCID: PMC7311058 DOI: 10.1021/acs.inorgchem.0c00079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
New examples of the very rare class
of iridium(I) Fischer carbene complexes (FCCs) are reported from the
facile transmetalation from group 6 FCCs. Postcomplexation modification
of either the carbene ligand or the ancillary coligands results in
a tunable IrI metal center, for unprecedented application
as a (pre)catalyst in a benchmark transfer hydrogenation reaction.
The introduction of an aminocarbene ligand with a pendant N-donor
moiety capable of hemilabile coordination yielded the best catalytic
results with turnover frequencies reaching 445 h–1 and requiring 0.1 mol % catalyst and 0.5 mol % base loading, respectively. A benchmark transfer hydrogenation is
catalyzed by an iridium(I) acyclic aminocarbene of the Fischer type
with a pendant N donor.
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Affiliation(s)
- G Kabelo Ramollo
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Ian Strydom
- Chemistry Department, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa
| | - Manuel A Fernandes
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Andreas Lemmerer
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Stephen O Ojwach
- School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, South Africa
| | - Juanita L van Wyk
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Daniela I Bezuidenhout
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.,Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
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Aucamp D, Kumar SV, Liles DC, Fernandes MA, Harmse L, Bezuidenhout DI. Synthesis of heterobimetallic gold(i) ferrocenyl-substituted 1,2,3-triazol-5-ylidene complexes as potential anticancer agents. Dalton Trans 2019; 47:16072-16081. [PMID: 30276400 DOI: 10.1039/c8dt03116a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
1,2,3-Triazol-5-ylidene (trz) complexes of gold(i) containing a ferrocenyl substituent on the C4-position of the trz ring were synthesized to yield the neutral heterobimetallic gold(i) trz chlorido (2), gold(i) trz phenyl (3), and the cationic gold(i) trz triphenylphospine (5) complexes. In order to compare the effect of silver(i) as central metal vs. gold(i), [Ag(trz)2]+ (4) was also prepared, while variation of the C4-1,2,3-triazol-5-ylidene substituent from a ferrocenyl to a phenyl group was done to prepare the monometallic analogue of 5, namely the cationic Au(i) trz triphenylphosphine complex 6. The complexes were characterised with spectroscopic and electrochemical methods, and the single crystal X-ray structures of 2-6 were determined. NMR stability studies of 5 as a representative example of the series of complexes were performed to confirm the stability of the complexes in the solvent dimethylsulfoxide and in aqueous solution. The anti-cancer potential of 5 was evaluated against the lung cancer cell lines A549 and H1975, and the human embryonic kidney cell line (HEK-293) was used as a non-cancer model. IC50 values of 0.89, 0.23 and 5.43 μM, respectively, were obtained for A549, H1975 and HEK-293, respectively, indicating the activity and selectivity of 5 for cancer cells. Fluorescence microscopy experiments as a preliminary mode-of-action study evidenced an apoptotic cell death mechanism rather than necrotic cell death.
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Affiliation(s)
- Danielle Aucamp
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.
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15
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Lamprecht Z, Moeng MM, Liles DC, Lotz S, Bezuidenhout DI. Thiophene site activation: Synthesis and structures of Fischer carbene complexes with 3,3′- and 2,3′-bithienyl substituents. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.10.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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Kleinhans G, Guisado-Barrios G, Peris E, Bezuidenhout DI. Ruthenium(II) pincer complexes featuring an anionic CNC bis(1,2,3-triazol-5-ylidene)carbazolide ligand coordinated in a meridional fashion. Polyhedron 2018. [DOI: 10.1016/j.poly.2017.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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17
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Lamprecht Z, Radhakrishnan SG, Hildebrandt A, Lang H, Liles DC, Weststrate NA, Lotz S, Bezuidenhout DI. Mono-, di- and tetrarhenium Fischer carbene complexes with thienothiophene substituents. Dalton Trans 2017; 46:13983-13993. [PMID: 28975955 DOI: 10.1039/c7dt02969a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The oxidative cleaving of a rhenium-rhenium bond by bromine in binuclear Fischer carbene complexes proves to be an effective method to prepare mononuclear bromido-carbene complexes. The reaction of mono- and dilithiated thieno[2,3-b]thiophene (2,3-b-TTH2) and thieno[3,2-b]thiophene (3,2-b-TTH2) with [Re2(CO)10] affords dirhenium nonacarbonyl ethoxycarbene complexes, [Re2(CO)9{C(OEt)2,3-b-TTH}] (1a) and [Re2(CO)9{C(OEt)3,2-b-TTH}] (1b), and the tetrarhenium bis(ethoxycarbene) complexes from the dilithiated thiophene substrates, [Re2(CO)9-μ-{C(OEt)-2,3-b-TT-C(OEt)}Re2(CO)9] (2a) and [Re2(CO)9-μ-{C(OEt)-3,2-b-TT-C(OEt)}Re2(CO)9] (2b) featuring bridging thiophene linkers. Rhenium-rhenium bond cleavage by bromine of the monocarbene complexes yielded the scarce class of monorhenium bromido-carbene complexes, cis-[Re(CO)4{C(OEt)2,3-b-TTH}Br] (3a) and cis-[Re(CO)4{C(OEt)3,2-b-TTH}Br] (3b), while the corresponding reaction of the biscarbene tetrarhenium carbonyl complex of thieno[2,3-b]thiophene afforded the cleaving of both metal-metal bonds to give the novel dirhenium biscarbene dibromido complex with a thienothiophene spacer, [Re(CO)4Br-μ-{C(OEt)-2,3-b-TT-C(OEt)}Re(CO)4Br] (4a). A new indirect aminolysis route is described to prepare the chlorido dimethylaminocarbene complex 5acis-[Re(CO)4{C(NMe2)2,3-b-TTH}Cl], with unexpected cleavage of the Re-Re bond. Single crystal X-ray diffraction studies were performed on 1a, 2a, 3a, 5a, 1b and 3b. Spectroscopic and electrochemical methods are employed to investigate the electronic effect of the different conjugation pathways in the different thienothiophenyl carbene substituents, and the replacement of the rhenium pentacarbonyl fragment with a bromido ligand.
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Affiliation(s)
- Zandria Lamprecht
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa.
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Aucamp D, Witteler T, Dielmann F, Siangwata S, Liles DC, Smith GS, Bezuidenhout DI. A Triarylated 1,2,3-Triazol-5-ylidene Ligand with a Redox-Active Ferrocenyl Substituent for Rhodium(I)-Catalyzed Hydroformylation of 1-Octene. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700164] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Danielle Aucamp
- Chemistry Department; University of Pretoria; Private Bag X20, Hatfield 0028 Pretoria South Africa
| | - Tim Witteler
- Institut für Anorganische und Analytische Chemie; Westfälische Wilhelms-Universität Münster; Corrensstrasse 30 48149 Münster Germany
| | - Fabian Dielmann
- Institut für Anorganische und Analytische Chemie; Westfälische Wilhelms-Universität Münster; Corrensstrasse 30 48149 Münster Germany
| | - Shepherd Siangwata
- Department of Chemistry; University of Cape Town; 7701 Rondebosch South Africa
| | - David C. Liles
- Chemistry Department; University of Pretoria; Private Bag X20, Hatfield 0028 Pretoria South Africa
| | - Gregory S. Smith
- Department of Chemistry; University of Cape Town; 7701 Rondebosch South Africa
| | - Daniela I. Bezuidenhout
- Chemistry Department; University of Pretoria; Private Bag X20, Hatfield 0028 Pretoria South Africa
- Molecular Sciences Institute; School of Chemistry; University of the Witwatersrand; 2050 Johannesburg South Africa
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Strydom I, Guisado-Barrios G, Fernández I, Liles DC, Peris E, Bezuidenhout DI. A Hemilabile and Cooperative N-Donor-Functionalized 1,2,3-Triazol-5-Ylidene Ligand for Alkyne Hydrothiolation Reactions. Chemistry 2016; 23:1393-1401. [DOI: 10.1002/chem.201604567] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Ian Strydom
- Chemistry Department; University of Pretoria; Private Bag X20 Hatfield 0028, Pretoria South Africa
| | - Gregorio Guisado-Barrios
- Institute of Advanced Materials (INAM); Universitat Jaume I; Avenida Vicente Sos Baynat s/n 12071 Castellon Spain
| | - Israel Fernández
- Departamento de Química Orgánica I; Facultad de Ciencias Químicas; Universidad Complutense de Madrid; 28040 Madrid Spain
| | - David C. Liles
- Chemistry Department; University of Pretoria; Private Bag X20 Hatfield 0028, Pretoria South Africa
| | - Eduardo Peris
- Institute of Advanced Materials (INAM); Universitat Jaume I; Avenida Vicente Sos Baynat s/n 12071 Castellon Spain
| | - Daniela I. Bezuidenhout
- Chemistry Department; University of Pretoria; Private Bag X20 Hatfield 0028, Pretoria South Africa
- Molecular Sciences Institute; School of Chemistry; University of the Witwatersrand; Johannesburg 2050 South Africa
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Kleinhans G, Hansmann MM, Guisado-Barrios G, Liles DC, Bertrand G, Bezuidenhout DI. Nucleophilic T-Shaped (LXL)Au(I)-Pincer Complexes: Protonation and Alkylation. J Am Chem Soc 2016; 138:15873-15876. [PMID: 27960301 DOI: 10.1021/jacs.6b11359] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We report the synthesis and reactivity of unusual T-shaped (LXL)Au(I)-pincer complexes, based on a carbazole framework flanked by two mesoionic carbenes (MICs). In contrast to other Au(I) complexes, these complexes react with electrophiles. Protonation and alkylation occur either at the metal or the ligand, depending on steric factors. Of particular interest, protonation at gold leads to an unprecedented cationic Au(III) hydride, which gives a 1H NMR resonance at δ -8.34 ppm. The reactivity of this "hydride", however, shows protic and not hydridic behavior.
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Affiliation(s)
- George Kleinhans
- Chemistry Department, University of Pretoria , Private Bag X20, Hatfield 0028, Pretoria, South Africa
| | - Max M Hansmann
- UCSD-CNRS Joint Research Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0358, United States
| | - Gregorio Guisado-Barrios
- Institute of Advance Materials (INAM), Universitat Jaume I , Avenida Vicente Sos Baynat s/n, 12071 Castellon, Spain
| | - David C Liles
- Chemistry Department, University of Pretoria , Private Bag X20, Hatfield 0028, Pretoria, South Africa
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093-0358, United States
| | - Daniela I Bezuidenhout
- Chemistry Department, University of Pretoria , Private Bag X20, Hatfield 0028, Pretoria, South Africa.,Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand , Johannesburg 2050, South Africa
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Kleinhans G, Guisado-Barrios G, Liles DC, Bertrand G, Bezuidenhout DI. A rhodium(i)–oxygen adduct as a selective catalyst for one-pot sequential alkyne dimerization-hydrothiolation tandem reactions. Chem Commun (Camb) 2016; 52:3504-7. [DOI: 10.1039/c6cc00029k] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
An air-stable rhodium(i)–oxygen adduct featuring a CNC-pincer ligand, based on 1,2,3-triazol-5-ylidenes, catalyzes the homo-dimerization and hydrothiolation of alkynes, affording the gem-enyne and α-vinyl sulfide isomers, respectively, with excellent selectivity.
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Affiliation(s)
| | | | - David C. Liles
- Chemistry Department
- University of Pretoria
- Pretoria
- South Africa
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555)
- Department of Chemistry and Biochemistry
- University of California
- San DiegoLa Jolla
- USA
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Ramollo GK, López-Gómez MJ, Liles DC, Matsinha LC, Smith GS, Bezuidenhout DI. Rhodium(I) Ferrocenylcarbene Complexes: Synthesis, Structural Determination, Electrochemistry, and Application as Hydroformylation Catalyst Precursors. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00843] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- G. Kabelo Ramollo
- Department
of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - María J. López-Gómez
- Department
of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - David C. Liles
- Department
of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Leah C. Matsinha
- Department
of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa
| | - Gregory S. Smith
- Department
of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa
| | - Daniela I. Bezuidenhout
- Department
of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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23
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Lamprecht Z, van Jaarsveld NA, Bezuidenhout DI, Liles DC, Lotz S. Synthesis and properties of mono- and dimetal Fischer multicarbene complexes derived from thiophene and thieno[2,3-b]thiophene. Dalton Trans 2015; 44:19218-31. [PMID: 26488538 DOI: 10.1039/c5dt03555d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Access to multicarbene complexes of a fused thienothiophene substrate was obtained by the use of the tetrabrominated thieno[2,3-b]thiophene precursor in a lithium-bromide exchange reaction, followed by nucleophilic attack on metal hexacarbonyls (M = Cr, W). Subsequent alkylation afforded unique triscarbene complexes [M(CO)4{{C(OEt)}2C6H1S2C(OEt)}M(CO)5] (M = Cr 12, W 13) featuring three non-equivalent carbene ligands on a single thiophene linker, as well as the bischelated tetracarbene complexes [M(CO)4{{C(OEt)}2C6S2{C(OEt)}2}M(CO)4] (M = Cr 14, W 15). The triscarbene complexes 12 and 13 are the first examples of multi-alkoxycarbene complexes featuring three non-equivalent carbene ligands. The reaction also afforded the chelated mononuclear biscarbene complexes [M(CO)4{C(OEt)}2C6H2S2] (M = Cr 10, W 11) in low yields. Similarly, employing tetrabromothiophene as precursor yielded the mononuclear chelate biscarbene complexes [M(CO)4{C(OEt)}2C4H2S] (M = Cr 6, W 7) and the dinuclear tetracarbene complexes [M(CO)4{{C(OEt)}2C4S{C(OEt)}2}M(CO)4] (M = Cr 8, W 9). Modification of the classic Fischer carbene synthetic methodology to a process of stepwise additions of lithiating agent and metal carbonyls to thieno[2,3-b]thiophene, facilitates the formation of the mixed metal biscarbene complex [W(CO)5C(OEt){C6H2S2}C(OEt)Cr(CO)5] 5, as analogue of the homonuclear biscarbene complexes [M(CO)5C(OEt){C6H2S2}C(OEt)M(CO)5], (M = Cr 3, W 4). The monocarbene complexes [M(CO)5{C(OEt)C6H3S2}], (M = Cr 1, W 2) were also obtained in high yields, and the molecular structures of the tungsten complexes, with the exception of 9 and 11, were confirmed by single crystal X-ray diffraction studies.
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Affiliation(s)
- Zandria Lamprecht
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa.
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24
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van der Westhuizen B, Matthäus Speck J, Korb M, Bezuidenhout DI, Lang H. (Spectro)electrochemical investigations on (ferrocenyl)thiophenes modified by tungsten Fischer carbenes. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2014.08.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bezuidenhout DI, van der Westhuizen B, Strydom I, Swarts PJ, Swarts JC, Fernández I. Synthesis and electrochemical investigation of chromium(0) ferrocenyl-substituted carbene complexes. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.07.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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26
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Bezuidenhout DI, van der Westhuizen B, Swarts PJ, Chatturgoon T, Munro OQ, Fernández I, Swarts JC. Redox Behaviour of Cymantrene Fischer Carbene Complexes in Designing Organometallic Multi-tags. Chemistry 2014; 20:4974-85. [DOI: 10.1002/chem.201304711] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Indexed: 12/31/2022]
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Bezuidenhout DI, Kleinhans G, Guisado-Barrios G, Liles DC, Ung G, Bertrand G. Isolation of a potassium bis(1,2,3-triazol-5-ylidene)carbazolide: a stabilizing pincer ligand for reactive late transition metal complexes. Chem Commun (Camb) 2014; 50:2431-3. [PMID: 24448261 DOI: 10.1039/c3cc49385g] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and X-ray crystal structure of a potassium adduct of a monoanionic CNC-pincer ligand featuring two mesoionic carbenes is reported. Owing to the peculiar electronic and steric properties of this ligand, the first neutral stable Ni(II)-hydride, and an unusual Cu(II) complex displaying a seesaw geometry, have been isolated.
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Affiliation(s)
- Daniela I Bezuidenhout
- Chemistry Department, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa.
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Bezuidenhout DI, van der Westhuizen B, Rosenthal AJ, Wörle M, Liles DC, Fernández I. Fischer-type gold(I) carbene complexes stabilized by aurophilic interactions. Dalton Trans 2014; 43:398-401. [PMID: 24202317 DOI: 10.1039/c3dt52961d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The synthesis and structure of rare acyclic alkoxy- and aminocarbene complexes of gold(i) are reported, including a novel ferrocenophane dinuclear biscarbene complex. X-Ray diffraction analyses and DFT calculations reveal that these complexes are stabilized by genuine aurophilic interactions.
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Affiliation(s)
- Daniela I Bezuidenhout
- Chemistry Department, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
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29
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Bezuidenhout DI, Fernández I, van der Westhuizen B, Swarts PJ, Swarts JC. Electrochemical and Computational Study of Tungsten(0) Ferrocene Complexes: Observation of the Mono-Oxidized Tungsten(0) Ferrocenium Species and Intramolecular Electronic Interactions. Organometallics 2013. [DOI: 10.1021/om400865m] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Daniela I. Bezuidenhout
- Department of Chemistry, University of Pretoria, Private Bag
X20, Hatfield 0028, Pretoria, South Africa
| | - Israel Fernández
- Departamento de Quı́mica Orgánica
I, Facultad de Ciencias Quı́micas, Universidad Complutense, 28040 Madrid, Spain
| | | | - Pieter J. Swarts
- Chemistry Department, University of the Free State, P.O. Box
339, Bloemfontein 9300, South Africa
| | - Jannie C. Swarts
- Chemistry Department, University of the Free State, P.O. Box
339, Bloemfontein 9300, South Africa
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van der Westhuizen B, Speck JM, Korb M, Friedrich J, Bezuidenhout DI, Lang H. Metal–Metal Interaction in Fischer Carbene Complexes: A Study of Ferrocenyl and Biferrocenyl Tungsten Alkylidene Complexes. Inorg Chem 2013; 52:14253-63. [DOI: 10.1021/ic402202w] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | - J. Matthäus Speck
- Fakultät
für Naturwissenschaften, Institut für Chemie, Anorganische
Chemie, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
| | - Marcus Korb
- Fakultät
für Naturwissenschaften, Institut für Chemie, Anorganische
Chemie, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
| | - Joachim Friedrich
- Fakultät
für Naturwissenschaften, Institut für Chemie, Theoretische
Chemie, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
| | | | - Heinrich Lang
- Fakultät
für Naturwissenschaften, Institut für Chemie, Anorganische
Chemie, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
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van der Westhuizen B, Swarts PJ, van Jaarsveld LM, Liles DC, Siegert U, Swarts JC, Fernández I, Bezuidenhout DI. Substituent Effects on the Electrochemical, Spectroscopic, and Structural Properties of Fischer Mono- and Biscarbene Complexes of Chromium(0). Inorg Chem 2013; 52:6674-84. [DOI: 10.1021/ic4007422] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
| | - Pieter J. Swarts
- Chemistry Department, University of the Free State, P.O. Box 339, Bloemfontein
9300, South Africa
| | - Louise M. van Jaarsveld
- Chemistry Department, University of Pretoria, Private Bag X20, Hatfield 0028,
Pretoria, South Africa
| | - David C. Liles
- Chemistry Department, University of Pretoria, Private Bag X20, Hatfield 0028,
Pretoria, South Africa
| | - Uwe Siegert
- Chemistry Department, University of the Free State, P.O. Box 339, Bloemfontein
9300, South Africa
| | - Jannie C. Swarts
- Chemistry Department, University of the Free State, P.O. Box 339, Bloemfontein
9300, South Africa
| | - Israel Fernández
- Departamento
de Química
Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Daniela I. Bezuidenhout
- Chemistry Department, University of Pretoria, Private Bag X20, Hatfield 0028,
Pretoria, South Africa
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van der Westhuizen B, Swarts PJ, Strydom I, Liles DC, Fernández I, Swarts JC, Bezuidenhout DI. Electrochemical illumination of thienyl and ferrocenyl chromium(0) Fischer carbene complexes. Dalton Trans 2013; 42:5367-78. [DOI: 10.1039/c3dt32913e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bezuidenhout DI, Lotz S, Liles DC, van der Westhuizen B. Recent advances in the field of multicarbene and multimetal carbene complexes of the Fischer-type. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2011.12.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Landman M, van Westhuizen B, Bezuidenhout DI, Liles DC. {μ-5-[1,3-Bis(2,4,6-trimethyl-phen-yl)-3H-imidazolium-2-yl]-2-(2-oxoethenyl-1κC)furan-3-yl-2κC}-μ-hydrido-bis(tetra-carbonyl-rhenium) tetra-hydro-furan 0.67-solvate. Acta Crystallogr Sect E Struct Rep Online 2012; 68:m308-9. [PMID: 22412450 PMCID: PMC3297260 DOI: 10.1107/s1600536812006587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 02/14/2012] [Indexed: 11/17/2022]
Abstract
The title complex, [Re2(C27H25N2O2)H(CO)8]·0.67C4H8O, was formed as a product in the reaction of a rhenium(I)–Fischer carbene complex with a free NHC carbene. The coordination environment about the two Re atoms is slightly distorted octahedral, including a bridging H atom. The imidazolium and furan groups are almost coplanar, whereas the mesityl substituents show an almost perpendicular arrangement with respect to both heterocyclic units. Molecules of the complex pack in such a way as to form channels parallel with the bc unit-cell face diagonal running through the unit face diagonal. These channels are partially occupied by tetrahydrofuran solvent molecules.
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Affiliation(s)
- Marilé Landman
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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35
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Landman M, van der Westhuizen B, Bezuidenhout DI, Liles DC. 1,3-Bis(2,4,6-trimethylphenyl)-3 H-imidazol-1-ium tetraoxidorhenate(VII). Acta Crystallogr Sect E Struct Rep Online 2011; 67:m1897. [PMID: 22199655 PMCID: PMC3238778 DOI: 10.1107/s1600536811050677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 11/25/2011] [Indexed: 11/10/2022]
Abstract
The title compound, (C21H25N2)[ReO4], was formed as the unexpected product in an attempted synthesis of a rhenium(I)–N-heterocyclic carbene (NHC) complex. The compound has crystallographic mirror symmetry with both the cation and the tetrahedral anion located across a mirror plane. The cation and anion are linked by a C—H⋯O hydrogen bond.
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Bezuidenhout DI, Lotz S, Landman M, Liles DC. Synthesis, characterization, and structural studies of multimetallic ferrocenyl carbene complexes of group VII transition metals. Inorg Chem 2011; 50:1521-33. [PMID: 21250683 DOI: 10.1021/ic101784w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fischer carbene complexes of the group VII transition metals (Mn and Re) containing at least two or three different transition metal substituents, all in electronic contact with the carbene carbon atom, were synthesized. The structural features and their relevance to bonding in the carbene multimetal compounds were investigated, as they represent indicators of possible reactivity sites in polymetallic carbene assemblies. For complexes of the type [ML(x){C(OR)R'}] (ML(x) = MnCp(CO)(2) or Re(2)(CO)(9)), ferrocenyl (Fc) was chosen as the R' substituent, while the OR substituent was systematically varied between an ethoxy or a titanoxy group, to yield the complexes 1a (ML(x) = MnCp(CO)(2), R = Et, R' = Fc), 2a (ML(x) = MnCp(CO)(2), R = TiCp(2)Cl, R' = Fc), 3a (ML(x) = Re(2)(CO)(9), R = Et, R' = Fc), and 4a (ML(x) = Re(2)(CO)(9), R = TiCp(2)Cl, R' = Fc). Direct lithiation of the ferrocene with n-BuLi/TMEDA at elevated temperatures, followed by the Fischer method of carbene preparation, resulted in formation of the novel biscarbene complexes with bridging ferrocen-1,1'-diyl (Fc') substituents [{π-Fe(C(5)H(4))(2)-C,C'}{C(OEt)ML(x)}(2)] (1b, ML(x) = MnCp(CO)(2); 3b, ML(x) = Re(2)(CO)(9)) or the unusual bimetallacyclic bridged biscarbene complexes [{π-TiCp(2)O(2)-O,O'}{π-Fe(C(5)H(4))(2)-C,C'}{CML(x)}(2)] (2b, ML(x) = MnCp(CO)(2); 4b, ML(x) = Re(2)(CO)(9)). The target compounds that were isolated displayed a variety of different geometric isomers and conformations. The greater reactivity of the binary dirhenium acylates in solution, compared to that of the cyclopentadienyl manganese acylate, resulted in a complex reaction mixture. Although the stabilization of hydroxycarbene or hydrido-acyl intermediates of dirhenium carbonyls could not be achieved, their existence in solution was confirmed by the isolation of [(π-H)(2)-(Re(CO)(4){C(O)Fc})(2)] (8), the unique dichloro-bridged biscarbene complex fac-[(π-Cl)(2)-(Re(CO)(3){C(OEt)Fc})(2)] (6), the known hydrido complex [Re(3)(CO)(14)H] (5), the acyl complex [Re(CO)(5){C(O)Fc}] (7), and the aldehyde-functionalized eq-[Re(2)(CO)(9){C(OTiCp(2)Cl)(Fc'CHO)}] (9).
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Affiliation(s)
- Daniela I Bezuidenhout
- Department of Chemistry, University of Pretoria, Lynnwood Road, Pretoria 0002, South Africa.
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37
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Bezuidenhout DI, Barnard W, van der Westhuizen B, van der Watt E, Liles DC. Multimetal Fischer carbene complexes of Group VI transition metals: synthesis, structure and substituent effect investigation. Dalton Trans 2011; 40:6711-21. [DOI: 10.1039/c1dt10183h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Lotz S, Landman M, Olivier AJ, Bezuidenhout DI, Liles DC, Palmer ER. Rhenium ethoxy- and hydroxycarbene complexes with thiophene substituents. Dalton Trans 2011; 40:9394-403. [DOI: 10.1039/c1dt10824g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Landman M, van der Westhuizen B, Bezuidenhout DI, Liles DC. N-(2,4,6-Trimethyl-phen-yl)formamide. Acta Crystallogr Sect E Struct Rep Online 2010; 67:o120. [PMID: 21522631 PMCID: PMC3050174 DOI: 10.1107/s1600536810051469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/08/2010] [Indexed: 11/25/2022]
Abstract
The title compound, C10H13NO, was obtained as the unexpected, almost exclusive, product in the attempted synthesis of a manganese(I)–N-heterocyclic carbene (NHC) complex. The dihedral angle between the planes of the formamide moiety and the aryl ring is 68.06 (10)°. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, forming infinite chains along the c axis.
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Affiliation(s)
- Marilé Landman
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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Lotz S, Crause C, Olivier AJ, Liles DC, Görls H, Landman M, Bezuidenhout DI. Synthesis and reactivity of metal carbene complexes with heterobiaryl spacer substituents. Dalton Trans 2009:697-710. [DOI: 10.1039/b811762d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bezuidenhout DI, van der Watt E, Liles DC, Landman M, Lotz S. Steric and Electronic Effects of Metal-Containing Substituents in Fischer Carbene Complexes of Chromium. Organometallics 2008. [DOI: 10.1021/om8001735] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Elisia van der Watt
- Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa
| | - David C. Liles
- Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa
| | - Marilé Landman
- Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa
| | - Simon Lotz
- Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa
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Bezuidenhout DI, Liles DC, van Rooyen PH, Lotz S. Axial and equatorial carbene ligands of dimanganese and dirhenium monocarbene complexes: Synthesis, characterisation and structural studies. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2006.10.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lotz S, Landman M, Bezuidenhout DI, Olivier AJ, Liles DC, van Rooyen PH. Metal–metal bond cleavage of carbene complexes by halogens: The crystal and molecular structures of ax-[Mn2(CO)9{C(OEt)2-thienyl}], [Mn(CO)4(I){C(OEt)2-thienyl}] and eq-[Mn2(CO)9{C(NH2)2-thienyl}]. J Organomet Chem 2005. [DOI: 10.1016/j.jorganchem.2005.07.090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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