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Mechanistic studies for the palladium-catalyzed decarboxylative cyclization reactions of [gamma]-methylidene-[delta]-valerolactones with isocyanates are described. This is the first systematic studies which provide insight into the selectivity between terminal attack and central attack at ([pi]-allyl)palladium species by nitrogen-based nucleophiles.

The properties of the putative common precursor for the S. zelandica decapropionates siphonarin B, caloundrin B, baconipyrone A, and baconipyrone C are examined for testing the hypothesis that siphonariid polypropionates has originated from nonenzymatic processes on acyclic biosynthetic precursors. The studies have shown that the baconipyrones are plausible isolation artifacts and are most likely derived from siphonarins rather than an 'acyclic' precursor.

Theoretical study of the alkaline hydrolysis of methyl p-nitrophenyl phosphate (MpNP[P.sup.-]) in aqueous solution and in the active site of nucleotide pyrophosphatase/phosphodiesterase (NPP) is presented. The analysis has shown that the reaction has taken place through different reaction mechanisms depending on the environment.

A new 1,3-diderivative of calix[4]arene appended with hydroxymethyl salicylyl imine is prepared and its ion recognition toward biologically relevant [M.sup.n+] ions is analyzed. The studies have shown that while [H.sub.2]L is selective for [Zn.sup.2+] among a number of cations, the [ZnL] is selective toward phosphate among a number of anions and also toward Asp, Cys and His among the naturally occurring amino acids.

The stereospecific synthesis of polyneuridine aldehyde, 16-epivellosimine, (+)-polyneuridine and (+)-macusine A is achieved from D-(+)-tryptophan methyl ester. The oxidation of the 16-hydroxymethyl group present in the axial position is achieved with the Corey-Kim reagent to give the [beta]-axial aldehydes, polyneuridine aldehyde and 16-epivellosimine with 100% diastereoselectivity.

Nanosecond laser flash photolysis methods are used to generate and spectrally characterize the cation radicals of 1,2-diaryl-1,1,2,2-tetramethyldisilanes in hexafluoroisopropanol (HFIP) at room temperature. The studies have shown that the oxidation of 1,2-di-p-methoxyphenyl-1,1,2,2-tetramethyldisilane by slow cyclic voltammetry in acetonitrile is not reversible.

The scope of HPP-COSY-based spectroscopy techniques are explored to characterize a diverse group of small organic molecules bearing di- and triphosphorylated moieties. The utility of the experiments to distinguish between mono- and diphosphates is demonstrated.

The synthesis of analogues of the two reverse phosphonohydroxamic acids is described, in which the length of the carbon spacer is modified, the N-methyl group of the acid is replaced by an ethyl group and the phosphate group is replaced by isosteric moieties like sulfonate or carboxylate functionalities. The potential of the analogues to inhibit the Escherichia coli 1-deoxy-D-xylulose 5-phosphate reducto-isomerase (DXR) is analyzed.

Picosecond soft X-ray spectroscopy was used to study the solution-phase photoinduced low-spin to high-spin conversion in the [Fe.sub.II] polypyridyl complex [[Fe(tren[(py).sub.3])].sup.2+] (where tren[(py).sub.3] is tris(2-pyridylmethyliminoethyl)amine). These results demonstrated the possibility and unique potential of time-resolved soft X-ray absorption spectroscopy to study ultrafast reactions in the liquid phase by directly probing the valence orbitals of first-row metals as well as lighter elements during the course of photochemical transformations.

The interaction of the agonist JN403 with the human (h) [alpha]7 nicotinic acetylcholine receptor (AChR) was compared to that for the competitive antagonist methyllycaconitine (MLA) to study the receptor selectivity of JN403 on the h[alpha]7, h[alpha]3[beta]4, and h[alpha]4[beta]2 AChRs. The results provide insight into the significance of the higher receptor specificity of JN403 for the treatment of [alpha]7-related disorders, including dementias, pain-related ailments, depression, anxiety, and wound healing.

An efficient synthesis and detailed experimental and spectral studies for C-1 derivatives of 7-deoxypancratistatin and trans-dihydrolycoricidine are reported. The C-1 acetoxymethyl derivatives exhibit promising biological activity against several cancer cell lines and in an apoptosis study.

Colloidal quantum dot solar cells are fabricated under ambient atmosphere with an active area that has displayed 3.6% solar power conversion efficiency. A novel ligand strategy is described in which the quantum dots are encapsulated in the solution phase with the help of a strongly bound N-2,4,6-trimethylphenyl-N-methyldithiocarbamate ligand.

The cloning and biochemical characterization of a novel methyl-1H-benzimidazol-2-ylcarbamate (MBC)-hydrolyzing esterase from the newly isolated Nocardioides sp. strain SG-4G and the proof-of-concept for the potential of radiation-killed, freeze-dried SG-4G cells in the bioremediation of MBC is described. The strong and stable MBC detoxification activity exhibited by radiation-killed and freeze-dried SG-4G cells could find suitable use in enzymatic bioremediation applications.

The pore volume and BET surface area of bio-MOF-1, [Zn.sub.8][(ad.sub.4])[(BPDC).sub.5]O.2[Me.sub.2]N[H.sub.2], is modified via postsynthetic cation exchange with either tetramethylammonium, tetraethylammonium or tetrabutylammonium cations to yield [Zn.sub.8][(ad).sub.4][(BPDC).sub.6]O.2[Me.sub.4]N, [Zn.sub.8][(ad).sub.4][(BPDC).sub.6]O.2[Et.sub.4]N, and [Zn.sub.8][(ad).sub.4][(BPDC).sub.6]O.2[[Bu.sub.4]N. The impact of pore volume and BET surface area on C[O.sub.2] capacity is analyzed and it is shown that materials with intermediate porosity have the largest C[O.sub.2] capacities under the conditions.

Octahedral group 4 bisphenolate ether complexes are activated by methylaluminoxane and are shown to be highly active and stereospecific [alpha]-olefin polymerization catalysts. The studies have shown that despite the structural similarity of the Hf and Zr complexes, the Hf complexes have generated more highly stereoselective catalysts.

A novel ring contraction which facilitates the direct conversion of N-chlorolactams to their corresponding ring-contraction N-heterocycles upon photolysis is reported. The rearrangement of a variety of N-chlorolactams to isolated methyl carbamates increased with the substitution at the migrating carbon.

The cycloaddition chemistry of aziridines as useful precursors to the azomethine ylide family of 1,3-dipoles are utilized in the synthesis of heterocyclic targets. The results from frontier molecular orbital theory, inductive, resonance, and electrostatic effects are considered demonstrated the preferred direction of rotation during ring cleavage that is based on substituent electron-withdrawing ability.

A convergent strategy with longest linear sequence of 23 steps was used to achieve a highly stereoselective joint total synthesis of the potent polyketide macrolide antibiotics etnangien and etnangien methyl ester. The expedient and flexible strategy of the etnangiens could be adapted to design analogues of these RNA-polymerase inhibitors and allow further exploration of the promising biological potential of these macrolide antibiotics.

The applicability of the O-HaN heterosynthon for synthesis of a pharmaceutical co-crystal comprised of a commonly used tablet excipient methyl paraben and quinidine, an anti-malarial constituent of Cinchona tree bark, is described. The studies have shown that methyl paraben has picked its target via hydrogen-bond-mediated molecular recognition, thereby acting as molecular hook.

An inflection seen in atomic mean square displacements measured as a function of temperature on high resolution spectrometers is described by the onset of methyl group rotations. Molecular dynamics simulations have shown that the apparent transition is because of methyl group rotation entering the infinite instrumental resolution of the spectrometer.

The temperature dependence of the deuterium kinetic isotope effect associated with the transfer of a hydrogen atom from methylaspartate to the coenzyme is examined to study the significant role of hydrogen tunneling to the mechanism of adenosylcobalamin-dependent enzymes. A significant degree of hydrogen tunneling is found to occur in glutamate mutase, even though the intrinsic kinetic isotope effects are well within the semiclassical limit and are much smaller than those measured for other AdoCbl enzymes and model reactions for which hydrogen tunneling is implicated.

A set of modular components is designed, prepared and combined to produce an innovative method for the self-assembly of large supramolecular structures on silicon wafers. The complete orthogonality of the two interactions has allowed the molecular level control of each step of the solid-state assembly and the response to precise external stimuli.