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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 24 for “"Nitrene"”.
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Nitrene transfer reactions by late transition metal complexes
This thesis presents nitrene transfer reactions that are catalyzed or mediated by late transition metal complexes. Sterically large, fluorinated supporting ligands are used to minimize potential side reactions. A new 1,10-phenanthroline ligand has been synthesized with 2,4,6-(CF3)3C6H2- groups in …
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Explore the Formation of Triplet Nitrene - A Potential Intermediate for Building Organic Magnets
… one the photoreactivity of the triplet vinyl nitrene, which is considerably stable. We have successfully utilized two ways to form the triplet vinyl nitrene by photolyzing 2H-Azirines and vinyl azides. We also studied the photoreactivity of alkyl azides containing the triplet sensitization …
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The Application and Evolution of Chiral Ion-Paired Rhodium(II,II) Tetracarboxylate Catalysts for Enantioselective Nitrene Transfer
… the investigations into enantioselective nitrene transfer chemistry employing chiral ion-paired dirhodium catalysts. The initial development of this catalyst family was reported previously by the Phipps group and their design is based on a strategy for the combination of transition metal …
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Characterizing triplet azo biradical and corannulene- halogen complexes by laser flash photolysis
… in halogenated solvents.</p><p>Singlet aryl nitrene was formed upon irradiation of aryl azides, and the singlet nitrene could decay by intersystem-crossing to form triplet nitrene or by direct ring expansion reaction to produce azepine. In solution the singlet aryl nitrene underwent ring …
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Entwicklung neuer Methoden zur Eisen-katalysierten Kohlenstoff-Heteroatom-Bindungsknüpfung
… to the aziridination reaction of olefins by nitrene group transfer. Commercial Fe(acac)3 served as the iron source. The nitrene was formed in situ from an aromatic sulfonamide and a hypervalent iodine compound under basic conditions. The conversion of various aromatic olefins gave moderate …
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Part One: Photochemistry of Aryl Azides. Chemical Properties of the Transient Intermediates. Part Two: Thermolysis of an Endoperoxide. Generation of an O-Xylylene Peroxide (Nitrene)
… Direct irradiation gives the triplet aryl nitrenes, with relatively long-lived singlet-state precursors. The structures of these intermediates and their rates of reaction with secondary amines are discussed.
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The Chemistry of Aroyl Azides in Piperidine- and Steroid-Separated Bichromophoric System: Photoinduced Long-Distance Intramolecular Electron Transfer Reactions
… by the photo-Curtius rearrangement and nitrene by loss of nitrogen. Light absorbed by the aryl amine donor chromophores initiates a through-bond electron-transfer reaction to form high energy, charge-separated intermediate states. The aryl amine radical cations were detected by pulsed …
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Asymmetric Dihydroxylation and Aziridination of Allenes and Related Chemistry
… were formed by copper-catalyzed intramolecular nitrene addition to alkenes. The carbamate group was used as the tether between the alkene and the nitrene. Subsequent nucleophilic attack of the aziridine was accomplished using RSH, R2NH, N3-,or ROH as the nucleophile. This addition was found to …
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New Catalysts for Asymmetric Nitrene Transfer Based on Ion-Pairing Between Sulfonated Rhodium(II,II) Tetracarboxylates and Chiral Cations: Design, Synthesis and Applications to Enantioselective Carbon-Nitrogen Bond Formation
New Catalysts for Asymmetric Nitrene Transfer Based on Ion-Pairing Between Sulfonated Rhodium(II,II) Tetracarboxylates and Chiral Cations: Design, Synthesis and Applications to Enantioselective Carbon-Nitrogen Bond Formation – Alexander Fanourakis The work presented in this thesis investigates a …
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Mass spectrometric characterization of remotely charged amino acids and peptides
… the electronic structure of 3- and 4-pyridinylnitrene-n-oxide radical anions. Reactions with nitric oxide are generally similar to those reported previously for other aromatic nitrene radical anions. In particular, phenoxide formation by nitrogen–oxygen exchange is observed with both isomers. …
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The Photochemistry of 3- and 4-Nitro Phenyl Azides
… or in a frozen glass at 77 K gives triplet nitrenes. The products of the reaction of triplet nitrenes depend on the power of the light source. Triplet 4-nitrophenyl nitrene dimerizes to form azobenzene at a diffusion controlled rate and reacts with the tertiary amine by single-electron …
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Metals in Chemistry and Biology: Computational Chemistry Studies
… performed on glutathione synthetase. (1) Copper nitrene complexes were computationally characterized, as these complexes have yet to be experimentally isolated. (2) Multireference calculations were carried out on a symmetric C2v chromium dimer derived from the crystal structure of the …
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Studies on complex pyridine alkaloids: Total synthesis of cystodytin J, diplamine, shermilamine B and of Micrococcin P1
… and a photochemical insertion of a triplet nitrene into a C-H bond. The overall yield of diplamine is 12% over 7 steps. The synthesis of shermilamine B involves 11 steps with the overall yield of 8%. The first total synthesis of the antitumor agent, Micrococcin P1, a member of the …
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Organophosphorus-Catalyzed Reductive Functionalization of Nitrocompounds via P(III)/P(V) Redox Couple
… employed as coupling partners to intercept the nitrene reactivity of nitro compounds derived oxazaphosphorane intermediates for direct reductive C–N coupling. This organophosphorus-catalyzed nitro deoxygenative platform was further developed to a tandem C–N coupling/cyclization sequence, …
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Developing C–H bond Functionalization, Organocatalytic Hydrophosphination Reactions and Anti-Invasion Agents
… monometallic iron imido MLMB species capable of nitrene group transfer do so by accessing high-spin states, although their instability limits their applications. Bimetallic species were proposed to improve stability, but these complexes are difficult to synthesize and appeared to be unreactive. …
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Investigations of Iron–Nitrogen Bonding at Synthetic Iron–Sulfur Clusters
… which takes on an iminyl ([NAr]•−) or triplet nitrene ([NAr]2•) configuration depending on the charge state of the molecule. Two-electron oxidation of [Fe4S4]+ anilido complexes results in formal aminyl radical reductive elimination, generating aniline, hydrazine, and/or azoarene as byproducts …
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Studies of oxime complexes
… of which has been rationalised in terms of nitrene intermediates. The complexes Fe(Ppo)2.H2O, Fe(Ppo)2 .2py and Fe(po)2.H2O were found to be high spin. This property contrasts the behaviour of iron(II) complexes derived from 2-nitrosophenols, which are low spin, and is rationalised in terms …
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Reactivity of a Low Valent Gallium Compound
… reaction with diborane resulted in the formal nitrene insertion into the B-B bond to produce a gallium diborylamide. DFT calculations revealed intermediate gallium alkylidene formation from the reaction of NacNacGa with diazomethane that upon reaction with the second equivalent of diazomethane …
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Antibacterial calcite created with a multilayer polyelectrolyte coating method
… of polyelectrolytes due to covalent bonding by nitrene insertion reactions when exposed to UV light. The adsorbed mass of polyelectrolytes on the mineral is measured with a Quartz Crystal Microbalance (QCM) and multiple beam interferometry. Atomic Force Microscopy (AFM) is used to measure the …
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Reactions of metal complexes with Lewis bases and their utilisation in the selective filtration of smoke
… and a complex tentatively formulated as the nitrene species, Fe(2-nq)2, were isolated. The reactivity of the Fe(nqo), complexes towards CO has been successfully utilised in the selective filtration of tobacco smoke. Both Fe(1-nqo)3, and Fe(2-nqo)3 were shown to be capable of significantly …
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