N-functionalised expanded-ring N-heterocyclic carbenes: Synthesis, structure and catalysis

The work presented in this thesis is concerned with the synthesis, metal coordination and applications of expanded (6- and 7-membered) N-functionalised heterocyclic carbenes. It is divided into four chapters, which cover the following areas of research. Chapter One includes the historical and literature review of preparations, reactions, and catalysis applications for different-types of NHC, while in Chapter Two, the syntheses characterisation and solid state properties of new 6- and 7-membered NHC salts (with Mes, DIPP, o-MeOPh and o-MeSPh A/-substituents) are discussed. A new method for synthesising saturated NHC salts, using potassium carbonate as a mild base for the deprotonation of the corresponding formamidines reacted with di-electrophiles under aerobic conditions is presented. Chapter Three describes the syntheses characterisation and solid state structure of rhodium and iridium complexes. Expansion of the ring provides carbenes with NCnhcN angle close to the sp2 angle (120 ), which forces the A/-substituents to bend closer to the metal center. Furthermore, the expanded carbenes are found to be more basic than their 5-membered analogues. The wide NCnhcN angles and greater donor abilities of the expanded NHC carbenes mean that their catalytic applications are interesting to study. Chapter Four presents the results of catalytic performance for the 6- and 7-membered NHC rhodium and iridium complexes in olefin hydrogenation reactions with molecular hydrogen. These complexes are also tested as catalysts in the transfer hydrogenation of ketones

Use of ring-expanded diamino- and diamidocarbene ligands in copper catalyzed azide-alkyne "click" reactions

The two-coordinate ring-expanded N-heterocyclic carbene copper­(I) complexes [Cu­(RE-NHC)₂]⁺ (RE-NHC = 6-Mes, 7-<i>o</i>-Tol, 7-Mes) have been prepared and shown to be effective catalysts under neat conditions for the 1,3-dipolar cycloaddition of alkynes and azides. In contrast, the cationic diamidocarbene analogue [Cu­(6-MesDAC)₂]⁺ and the neutral species [(6-MesDAC)­CuCl]₂ and [(6-MesDAC)₂(CuCl)₃] show good activity when the catalysis is performed on water

N-functionalised expanded-ring N-heterocyclic carbenes : synthesis, structure and catalysis

The work presented in this thesis is concerned with the synthesis, metal coordination and applications of expanded (6- and 7-membered) N-functionalised heterocyclic carbenes. It is divided into four chapters, which cover the following areas of research. Chapter One includes the historical and literature review of preparations, reactions, and catalysis applications for different-types of NHC, while in Chapter Two, the syntheses characterisation and solid state properties of new 6- and 7-membered NHC salts (with Mes, DIPP, o-MeOPh and o-MeSPh A/-substituents) are discussed. A new method for synthesising saturated NHC salts, using potassium carbonate as a mild base for the deprotonation of the corresponding formamidines reacted with di-electrophiles under aerobic conditions is presented. Chapter Three describes the syntheses characterisation and solid state structure of rhodium and iridium complexes. Expansion of the ring provides carbenes with NCnhcN angle close to the sp2 angle (120 ), which forces the A/-substituents to bend closer to the metal center. Furthermore, the expanded carbenes are found to be more basic than their 5-membered analogues. The wide NCnhcN angles and greater donor abilities of the expanded NHC carbenes mean that their catalytic applications are interesting to study. Chapter Four presents the results of catalytic performance for the 6- and 7-membered NHC rhodium and iridium complexes in olefin hydrogenation reactions with molecular hydrogen. These complexes are also tested as catalysts in the transfer hydrogenation of ketones.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Synthesis, Characterization, and Anticancer Activity of Phosphanegold(i) Complexes of 3-Thiosemicarbano-butan-2-one Oxime

Four novel phosphanegold(I) complexes of the type [Au(PR3)(DMT)].PF6 (1–4) were synthesized from 3-Thiosemicarbano-butan-2-one oxime ligand (TBO) and precursors [Au(PR3)Cl], (where R = methyl (1), ethyl (2), tert-butyl (3), and phenyl (4)). The resulting complexes were characterized by elemental analyses and melting point as well as various spectroscopic techniques, including FTIR and (1H, 13C, and 31P) NMR spectroscopy. The spectroscopic data confirmed the coordination of TBO ligands to phosphanegold(I) moiety. The solution chemistry of complexes 1–4 indicated their stability in both dimethyl sulfoxide (DMSO) and a mixture of EtOH:H2O (1:1). In vitro cytotoxicity of the complexes was evaluated relative to cisplatin using an MTT assay against three different cancer cell lines: HCT116 (human colon cancer), MDA-MB-231 (human breast cancer), and B16 (murine skin cancer). Complexes 2, 3, and 4 exhibited significant cytotoxic effects against all tested cancer cell lines and showed significantly higher activity than cisplatin. To elucidate the mechanism underlying the cytotoxic effects of the phosphanegold(I) TBO complexes, various assays were employed, including mitochondrial membrane potential, ROS production, and gene expression analyses. The data obtained suggest that complex 2 exerts potent anticancer activity against breast cancer cells (MDA-MB-231) through the induction of oxidative stress, mitochondrial dysfunction, and apoptosis. Gene expression analyses showed an increase in the activity of the proapoptotic gene caspase-3 and a reduction in the activity of the antiapoptotic gene BCL-xL, which supported the findings that apoptosis had occurred

Base free transfer hydrogenation using a covalent triazine framework based catalyst

[EN] Isomerisation of allylic alcohols to saturated ketones can be efficiently catalysed by a heterogeneous molecular system resulting from (IrCp)-Cp-III* anchoring to a covalent triazine framework. The obtained catalysts are active, selective, and fully recyclable.Financial support from the Generalitat Valenciana (projects Consolider-Ingenio MULTICAT and AICO/2015/065), the Spanish Ministry of Economy and Competitiveness (MINECO) (program Severo Ochoa SEV20120267), and the Spanish Ministry of Science and Innovation (MICINN) (project MAT2014-52085-C2-1-P) are gratefully acknowledged. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 641887 (project acronym: DEFNET). Also, financial support from the European Union Seventh Framework Programme (FP7/2007-2013) under the grant agreement number 309701, project Eco2CO2 is acknowledged.Bavykina, A.; Mautschke, H.; Makkee, M.; Kapteijn, F.; Gascon, J.; Llabrés I Xamena, FX. (2017). Base free transfer hydrogenation using a covalent triazine framework based catalyst. CrystEngComm. 19(29):4166-4170. https://doi.org/10.1039/C7CE00561JS416641701929Wang, D., & Astruc, D. (2015). The Golden Age of Transfer Hydrogenation. Chemical Reviews, 115(13), 6621-6686. doi:10.1021/acs.chemrev.5b00203Cirujano, F. G., Leyva-Pérez, A., Corma, A., & Llabrés i Xamena, F. X. (2013). MOFs as Multifunctional Catalysts: Synthesis of Secondary Arylamines, Quinolines, Pyrroles, and Arylpyrrolidines over Bifunctional MIL-101. ChemCatChem, 5(2), 538-549. doi:10.1002/cctc.201200878Khajavi, H., Stil, H. A., Kuipers, H. P. C. E., Gascon, J., & Kapteijn, F. (2013). 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Differentially Substituted Acyclic Diaminocarbene Ligands Display Conformation-Dependent Donicities

Complexes of the type [(L)Ir(COD)Cl] and [(L)Ir(CO)(2)Cl] (L = N,N&apos;-dimesityl-N,N&apos;-dimethylformamidin-2-ylidene (3) and N,N&apos;-bis(2,6-di-isopropylphenyl)-N,N&apos;-dimethylformamidin-2-ylidene (4); COD = cis,cis-1,5-cyclooctadiene) were synthesized and studied in solution as well as in the solid state. While the acyclic diaminocarbene (ADC) ligand in [(3)Ir(COD)Cl] adopted a conformation in which the N-aryl substituents were anti with respect to the coordinated metal, the respective Ir carbonyl complex was prepared as separable isomers ([(anti-3)Ir(CO)(2)Cl] and [(amphi-3)Ir(CO)(2)Cl]). The ADC ligands in [(4)Ir(COD)Cl] and [(4)Ir(CO)(2)Cl] adopted exclusively amphi conformations, where one N-aryl substituent was oriented toward the coordinated metal and the other was oriented away. The Tolman electronic parameter (TEP) for anti-3 (2047.8 cm(-1)) was derived from the carbonyl stretching energy (v(CO)) of the aforementioned Ir(CO)(2)Cl complex and was found to be larger than the TEPs calculated for amphi-3 (2044.4 cm(-1)) and 4(2044.0 cm(-1)). Likewise, the oxidation potential of [(anti-3)Ir(CO)(2)Cl], as measured by cyclic voltammetry, was found to be significantly higher (1.57 V) than the analogous oxidation potentials measured for [(amphi-3)Ir(CO)(2)Cl] (1.26 V) and [(4)Ir(CO)(2)Cl] (1.24 V)