Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 106 for “"N-heterocyclic"”.
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Coinage Metal Chalcogenide Clusters with N-Heterocyclic Carbene Ancillary Ligands
… group 11 – group 16 clusters with N-heterocyclic carbene (NHC) ligands. The clusters were prepared from reactive group 11 trimethylsilylchalcogenolate reagents (NHC-M-ESiMe3; M = Cu, Au; E = S, Se, Te) by silane deprotection reactions with phosphine- or phosphite-solubilized group 11 …
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N-heterocyclic Carbene Synthesis Towards Self-Assembled Monolayers on Gold
… bond strength and surface stability of n heterocyclic carbenes (NHCs) to a gold substrate. Here in we report the synthesis and modification of gold surfaces with NHCs containing unique functionality. Chemical synthesis was characterized using nuclear magnetic resonance spectroscopy …
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Introduction of a Novel Family of Bitopic N-Heterocyclic Carbenes
… to greener production and a decrease in cost. N-heterocyclic carbenes (NHCs) have been recognized as a powerful class of ligands to metals, perhaps most notably in catalysis. This thesis introduces a family of bis-NHC ligands. This family links the N-alkylated benzimidazolium moieties by a bridge …
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Fischer and N-heterocyclic carbene complexes of Group (VII) transition metals
… and catalytic application of Fischer- and N-heterocyclic carbene (NHCs) complexes of the group VII transition metals were investigated. By using density function theory calculations, the structural and electronic parameters could be elucidated and the fundamental bonding interactions between …
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Synthetic and catalytic studies of Group 11 N-heterocyclic carbene complexes
… Group 11 metal complexes, supported by N-heterocyclic carbene (NHC) ligands. The NHC ligand was found to stabilize monomeric, terminal fluoride complexes of copper, silver and gold, the last representing the first isolable gold(I) fluoride. These complexes were shown to be reactive …
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Coordination Chemistry of Fe–S Clusters Supported by N-Heterocyclic Carbenes
… on adjacent metal sites (here, monodentate N-heterocyclic carbenes), to obtain [Fe₄S₄] clusters for which subsequent reactivity can be localized to a single Fe site. That is, the steric bulk of di-aryl NHC ligands enables isolation of [Fe₄S₄] clusters in which three of the Fe centers are …
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Synthesis, Activation and Catalytic Activity of N-Heterocyclic Carbene Bearing Palladium Catalysts
… of a series of (NHC)Pd(II) complexes (NHC = N-heterocyclic carbene) are described. A variety of architectures and precursors have been employed to lead to numerous air- and moisture-stable complexes. The use of those complexes as pre-catalysts in cross-coupling (Suzuki- Miyaura, …
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Novel N-heterocyclic activations mediated by magnesium reagents having sterically hindered ligands
… within the areas of deprotonative metallation, heterocyclic activation and catalytic application in hydroamination reactions of organic heterocumulenes. Firstly, a series of novel sodium magnesiates bearing the sterically demanding bis(amido)silyl ligand {Ph2Si(NAr*)2}2- (Ar*= 2,6-i-Pr2-C6H3) …
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Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes
The study involves synthetic approaches towards the preparation of novel NHC complexes of low valent rhenium and manganese transition metals. Diverse methods of synthesis were studied. The direct approach, in which the ylidene obtained from deprotonation of 1,3-bis(2,4,6- …
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A New 2,1,3-Benzothiadiazole-Fused N-Heterocyclic Carbene and Its Metal Complexes
<p>In the last few decades, N-heterocyclic carbenes (NHCs) have emerged as a powerful class of carbon-based ligands. Owing to their unique electronic and steric properties, they have been incorporated in a large variety of catalytically active metal complexes. One of the strategies that have been …
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Scanning Probe Study of N-Heterocyclic Carbene Self-Assembly on Coinage Metal Surfaces
… the standard surface anchor. More recently, N-heterocyclic carbenes (NHCs) have gained interest due to their increased oxidative and thermal robustness relative to the thiol. Since the emergence of NHCs in surface science, several key insights into how their structure relates to their …
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Synthesis of Well-Defined N-Heterocyclic Carbene (NHC) Complexes of Late Transition Metals
N-heterocyclic carbenes (NHCs) have emerged as appropriate replacements for phosphines to synthesized highly active metal complexes in homogeneous catalysis. The advantages of NHCs over phosphines include ease of handling, minimal toxicity and powerful electron donating properties. They bind …
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Development of Cobalt and Nickel N-Heterocyclic Carbene Complexes for Cross-Coupling Reactions
Cross-coupling, which relies on the use of transition metals, is among the most utilized chemical means of establishing carbon-carbon or carbon-heteteroatom bonds between appropriately functionalized sp, sp2, or sp3 centres. However, most cross-coupling reactions rely on the use of palladium to …
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(N-heterocyclic-carbene)Copper(I)-catalyzed carbon-carbon bond formation using carbon dioxide
This thesis presents work towards the development of a new catalytic C-C bond forming reaction. Alkynes and olefins insert into [(IPr)CuH]2 (IPr = N,N-bis-(2,6-diisopropylphenyl)-1,3-imidazol-2-ylidene) to give copper vinyl and copper alkyl complexes. These copper complexes insert CO2 into the Cu-C …
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Self-Assembled Monolayers of N-Heterocyclic Carbenes on Gold and Silver: Applications in Biosensing
… standard. Our group has described a series of N-heterocyclic carbenes (NHC) which form SAMs on gold. As the carbene is attached to the surface via a metal-carbon bond, the problem of sulfidization may be overcome. Here, I describe the synthesis of a peptide for the application of heavy metal …
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N-Heterocyclic Carbenes of the Late Transition Metals: A Computational and Structural Database Study
… study of the bonding in late transition metal N-heterocyclic carbene (NHC) complexes is reported. The results illustrate a metal-carbon bond for these complexes, approximately 4% shorter than that of a M-C single bond found in metal alkyl complexes. As a consequence of this result, two hypotheses …
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Dianionic Janus-Type N-Heterocyclic Carbenes and their Zwitterionic Gold and Silver Metal Complexes
… chemistry of neutral multitopic nonchelating N-heterocyclic carbenes (NHCs), limited progress has been made in the development of anionic counterparts. This thesis describes the synthesis and characterization of two new dianionic bis(maloNHC). The corresponding thiones were generated by the …
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Molecular-level study of N-heterocyclic carbenes: Binding modes and self-assembly on Au(111)
… have been the gold-standard for thirty years, N-heterocyclic carbenes (NHCs) have recently been used to create SAMs that are more thermally and chemically stable. For example, NHCs based on diisopropyl benzimidazolylidene (NHCiPr) have been integrated into biosensors. The field of NHC-based …
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Development of N-Heterocyclic Carbenes as Organic Catalysts and Efficient Ligands in Palladium Mediated Transformations
N-Heterocyclic carbenes (NHCs) have emerged as appropriate replacements for phosphines in transition metal catalyzed cross-coupling chemistry. The advantages of NHCs over phosphines include ease of handling, minimal toxicity, stability and powerful electron donating properties. Improvement of …
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