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A previously unknown cascade reaction in which two units of a rhodium(II)-stabilized vinylcarbene obtained from methyl trans-styryldiazoacetate react with benzylideneaniline is described; the products of the cascade reaction ...

NMR spin relaxation spectroscopy is a proven method for characterization of the time-scales and amplitudes of intramolecular motions in proteins. In a typical NMR relaxation experiment, the significant contributions to ...

New nanostructures and functional materials are built through the self-assembly of guanosine. Both the size and regiochemistry of these noncovalent structures are controlled. Lipophilic G-quadruplexes are further stabilized ...

Correlation detection techniques (image labeling, coincidence imaging, and joint variance) are developed with an image spectrometer capable of collecting charges ejected over 4\pi sr and a digital camera synchronized with ...

Nanoclusters are of interest because of their remarkable catalytic properties and their application in nanotechnology fields. There is a strong preference toward bimetallic systems due to their superior catalytic properties ...

Transition metal main group clusters have been studied extensively as models for heterogeneous catalysts and metal surface reactions. In this thesis, reactions of Group 14 Zintl ion cluster Pb94- with the Au precursor ...

The RecD helicase is a member of the RecBCD complex, which is essential for repair of double-stranded breaks (DSBs) in DNA via homologous recombination in Escherichia coli. The microbe Deinococcus radiodurans is capable ...

Our aim was to investigate the conformational properties of two tau fragments, 2R and 3R, in response to increasing amounts of a hydrogen-bond stabilizing solvent trifluoroethanol. 2R and 3R contain two or three of the ...

The objective of the thesis was to understand the chemical and kinetic behavior of arylnitrenium ions and a heteroaromatic nitrenium ion through photolytic studies. N-(4,4'-dichlorodiphenyl) nitrenium ion and N-(4,4'-dibromodiphenyl) nitrenium ion are the halogenated counterparts of diphenylnitrenium ions and are generated photochemically from their respective N-(4,4'-dihalogenated diphenylamino)-2,4,6-trimethylpyridinium tetrafluoroborate salts. The halogenated diarylnitrenium ions are ground state singlets that live for more than 1 x 10⁵ ns in acetonitrile. In the absence of nucleophiles, these ions decay to form a dimerized hydrazine. These ions react with nucleophiles such as water and alcohol at a rate constant of 10⁴ - 10⁵M^-1s^-1 and at diffusion limit with chlorides. With arenes, these ions react via electron transfer mechanism and nucleophilic addition process. The rate constants for the electron transfer mechanisms are between 10⁵ - 10⁹ M^-1 s^-1 and depend on the Eox of the arenes. Arenes with Eox above 1.78 V showed no reactivity towards the ion. Unlike other diarylnitrenium ions, the halogenated diarylnitrenium ions react with hydrogen atom donors via a hydrogen atom transfer mechanism. The triplet behavior of these ions is attributed to singlet-triplet intersystem crossing facilitated by the lower singlet-triplet energy gap. Therefore, it has been concluded that substituting halogens in diphenylnitrenium ion lowers the singlet-triplet energy gap and increases the lifetime of these ions. (N-Methyl-N-4-biphenylyl) nitrenium ion generated by photolysis was reacted with amino acids and proteins to determine their reactivity with these ions. Eight amino acids were observed to react with the ion at a rate constant of 10⁷ - 10⁹ M^-1 s^-1. The rate constants depend on the nucleophilicity of the side chains of the amino acids. In addition, this ion also reacts rapidly with proteins with a rate constant of 10⁸ M^-1 s^-1, comparable to their reactions with ss-DNA. Investigations on generating the quinoline N-oxide nitrenium ions showed that the transient species from the photolysis of 4-azidoquinoline N-oxide (4-AzQO) shows more characteristics of a nitrenium ion. The formation of 4-aminoquinoline N-oxide upon photolysis of 4-AzQO in acetonitrile with 10% sulphuric acid and the electron transfer reactions observed with arenes, indicate that the transient species generated could be a heteroaromatic nitrenium ion. However, more experiments are needed to confirm the assignment....

The cationic cyclopentadienyl zirconium acetamidinate (CPZA) complex {Cp*ZrMe[N(Et)C(Me)N(tBu)]}[B(Csub6 Fsub5)sub4], (Cp* = ηsup5-Csub5Mesub5) generated through activation of Cp*ZrMesub2[N(Et)C(Me)N(tBu)] via protonolysis ...