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A fundamental understanding of the role of catalysts in dehydrogenation of Mg[H.sub.2] nanocluster is provided by carrying out first-principles calculations based on density functional theory. It is shown that the transition metal atoms Ti, V, Fe, and Ni not only lower desorption energies significantly but also continue to attract at least four hydrogen atoms even when the total hydrogen content of the cluster decreases. In particular, Fe is found to migrate from the surface sites to the interior sites during the dehydrogenation process, releasing more hydrogen as it diffuses. This diffusion mechanism may account for the fact that a small amount of catalysts is sufficient to improve the kinetics of Mg[H.sub.2], which is essential for the use of this material for hydrogen storage in fuel-cell applications. hydrogen storage | transition metals | diffusion | catalysis

Toluate dioxygenase of Pseudomonas putida mt-2 ([TADO.sub.mt2]) and benzoate dioxygenase of Acinetobacter calcoaceticus ADP1 ([BADO.sub.ADP1]) catalyze the 1,2-dihydroxylation of different ranges of benzoates. The catalytic component of these enzymes is an oxygenase consisting of two subunits. To investigate the structural determinants of substrate specificity in these ring-hydroxylating dioxygenases, hybrid oxygenases consisting of the subunit of one enzyme and the [beta] subunit of the other were prepared, and their respective specificities were compared to those of the parent enzymes. Reconstituted [BADO.sub.ADP1] utilized four of the seven tested benzoates in the following order of apparent specificity: benzoate > 3-methylbenzoate > 3-chlorobenzoate > 2-methylbenzoate. This is a significantly narrower apparent specificity than for [TADO.sub.mt2] (3-methylbenzoate > benzoate ~ 3-chlorobenzoate > 4-methylbenzoate ~ 4-chlorobenzoate [much greater than] 2-methylbenzoate ~ 2-chlorobenzoate [Y. Ge, F. H. Vaillancourt, N. Y. Agar, and L. D. Eltis, J. Bacteriol. 184:4096-4103, 2002]). The apparent substrate specificity of the [[alpha].sub.b][[beta].sub.T] hybrid oxygenase for these benzoates corresponded to that of [BADO.sub.ADP1], the parent from which the [alpha] subunit originated. In contrast, the apparent substrate specificity of the [[alpha].sub.T][[beta].sub.B] hybrid oxygenase differed slightly from that of [TADO.sub.mt2] > (3-chlorobenzoate > 3-methyibienzoate > benzoate ~ 4-methylbenzoate > 4-chlorobenzoate > 2-methylbenzoate > 2-chiorobenzoate). Moreover, the [[alpha].sub.T][[beta].sub.B] hybrid catalyzed the 1,6-dihyiroxyliation of 2-methyilbenzoate, not the 1,2-dihydroxylation catalyzed by the [TADO.sub.mt2] parent. Finally, the turnover of this ortho-substituted benzoate was much better coupled to [O.sub.2] utilization in the hybrid than in the parent. Overall, these results support the notion that the [alpha] subunit harbors the principal determinants of specificity in ring-hydroxylating dioxygenases. However, they also demonstrate that the [beta] subunit contributes significantly to the enzyme's function.

NADP is essential for biosynthetic pathways, energy, and signal transduction. In living organisms, NADP biosynthesis proceeds through the phosphorylation of NAD with a reaction catalyzed by NAD kinase. We expressed, purified, and characterized Bacillus subtilis NAD kinase. This enzyme represents a new member of the inorganic polyphosphate [poly(P)]/ATP NAD kinase subfamily, as it can use poly(P), ATP, or other nucleoside triphosphates as phosphoryl donors. NAD kinase showed marked positive cooperativity for the substrates ATP and poly(P) and was inhibited by its product, NADP, suggesting that the enzyme plays a major regulatory role in NADP biosynthesis. We discovered that quinolinic acid, a central metabolite in NAD(P) biosynthesis, behaved like a strong allosteric activator for the enzyme. Therefore, we propose that NAD kinase is a key enzyme for both NADP metabolism and quinolinic acid metabolism.

Research has been conducted on the single- and double mutant flavocytochromes c (sub)3. The structure of the one of these enzymes indicate the existence of a water molecule at the enzyme's active site.

Research has been conducted on the sterically hindered and unhindered alkyl nitriles and on benzyl and phenyl nitriles. The hydrolysis of these nitriles to carboxamides has been catalyzed via zinc(II)/ketoxime combination and the results are reported.

Research has been conducted on the allyl aromatic compounds. The synthesis of these compounds which does not involve metal-containing reagents or catalysts has been investigated and the results are reported.

Research has been conducted on sodium tetraalkynylaluminates. The preparation of these compounds from NaAlH (sub)4 and terminal alkynes in the presence of palladium(0) and palladium(II) catalysts is described.

Research has been conducted on the cyclic compounds with the trisubstituted double bonds. Results indicate that these compounds affect olefin metathesis via the user of Grubbs catalyst.

Research has been conducted on the polypyridyl type ligands. The deuteriation of these ligands has been carried out via the use of the Pd/C catalyst and D (sub)2 O as a deuterium source and the details are reported.

Research has been conducted on the antimony compounds used as catalysts for the polymer poly(ethyleneterphthalate) synthesis. The catalytic nature of the species has been investigated via the structural characterization of antimony ethylene glycolate compounds and catecholate derivatives.

Research has been conducted on the catalyst for Wittig-type olefination and dehalogenation reactions. The development of this catalyst and the details of these reactions are reported.

Research has been conducted on the multiple dendritic ligands based on chiral diamine. The synthesis and application of the dendritic catalysts to the chiral diamine based ligands at the periphery are discussed.

Research has been conducted on bismuth triflate. The use of this compound as a catalyst for conversion of aldehydes and ketones to acetals is described.

Research has been conducted on amides, sters and carboxylic acids. The reduction of these compounds with trialkylsilanes has been carried out via the use of triruthenium carbonyl cluster with the bridging acenaphthylene ligand as a catalyst.

Research has been conducted on the FeCl (sub)3 -PPh (sub)3 complex. The study of this complex has indicated that it catalyzes electrophilic diamination reaction of the electron-deficient alkenes.

Research has been conducted on Pseudomonas aeruginosa's proline 293 of p-hydroxybenzoate hydroxylase. The peptide segment flexibility in catalysis has been investigated via the substitution of this hydroxylase with serine by site-directed mutagenesis

Research has been conducted on the catalytic histidine 447. The nature of the putitive array of interactions optimizing histidine 447 orientation has been explored and the details are reported.

Research has been conducted on the enzyme catalysis and allosteric regulation. The use of various kinetic methods in investigating the dynamics of these processes is discussed.

Research has been conducted on the aromatic amino acids. The synthesis of the optically active aromatic, thiophenyl, pyrrolyl and furfuryl alpha-amino acid derivatives has been carried out via the use of chiral Lewis acid catalysis and the results indicate that the protected heteroaromatic and aromatic alpha-amino acids can be produced via the addition of aromatic and heteroaromatic C-H bonds to alpha-amino ester electrophiles.

Research has been conducted on the idolizidine alkaloid (-)-swainsonine. The enantioselective synthesis of this alkaloid has been carried out starting from oxazolidinone and the efficiency of the metal-catalyzed reactions is discussed.

Research has been conducted on Diels-Alder reactions. The catalysis of these reactions by noncovalent synthetic, nucleic acid and protein host binding has been investigated and the details are reported.

Research has been conducted on the methyl aryldiazoacetates. The tetrakis-catalyzed decomposition of these compounds carried out in the presence of substituted ethylbenzenes has led to the C-H activation via the rhodium-carbenoid-induced C-H insertion and the details are presented.

Research has been conducted on the acylnitroso hetero Diels-Alder cycloadducts. Results indicate that the treatment of these cycloadducts with the organomagnesium reagents carried out in the presence of copper induces ring opening and produces monocyclic anti-1,2-hydroxamic acids.

Research has been conducted on the cyclic ureas. The results of the oxidative carbonylation of 1,3-propanediamine to the urea carried out under different conditions are presented.

Research has been conducted on the 4'-substituted nucleoside analogues. The synthesis of these analogues carried out via palladium-catalyzed asymmetric allylic amination conditions is described.

Research has been conducted on the peptide acetals. The results of biocyclization of these acetals via the phenyl group's nucleophilic reaction with endocyclic acyliminium ion are described.

Research has been conducted on Streptomyces viridosporus A-914. The isolation of the acidomycete strains producing half esters and cloning of the gene which is responsible for S. viridosporus A-914 enzyme and the expression of this enzyme in the parent strain are discussed.

The authors review the publications on lanthanide reagents and catalysts. The topics of interest include chiral complexes and ligands, asymmetric catalysis and nonlinear effects and Diels-Alder reaction.

The authors review the publications on asymmetric catalysis. The topics of interest include heterobimetallic catalysts based on lanthanide and lithium, alkali-metal-free lanthanide complexes and related lanthanide complexes.

The authors review the publications on lanthanide metallocenes. The topics of interest include application of these catalytic species to the synthesis of small organic molecules via the alkyne and alkene insertion reactions.

Research has been conducted on the allylic alcohols. The reaction of the allylic alcohol with olefins in the presence of benzoic acid, 2-amino-4-picoline and RhCl(PPh (sub)3) (sub)3 in producing aliphatic ketones is described.

Research has been conducted on the carbonates and trichlorobenzoate. The metal-catalyzed allylic substitution reaction of these compounds has been investigated and the metal complexes which contain iridium, palladium, tungsten, rhodium and molybdenum have been compared as catalysts.

Research has been conducted on the air-stable palladium complexes. Results indicate that these complexes serve as catalysts for the vinyl and aryl chloride cross-coupling reactions with thiols, arylzinc reagents and arylboronic acids.

Research has been conducted on the Michael addition reaction. The results of the 1,4-addition of alpha-amino ester's higher nitroalkanes, primary alcohols and a Schiff base to alpha,beta-unsaturated substrates are reported.

Research has been conducted on the small autocatalytic RNA motif, hammerheads ribozyme. Hammerhead dynamics has been investigated via the preparation of the covalent cross-linked hammerheads with different linked lengths and the results of their catalytic property characterization are presented.

Research has been conducted on the chital fluoro ketones. The preparation of these ketones has been carried out in examining their potential as enantioselective catalysts for the asymmetric epoxidation with Oxone and the details are described.

Research has been conducted on the heteroaromatic compounds. The reaction of furans, thiophenes, thiazoles and pyrroles with alkylidenecyclopropanes has been carried out in the presence of palladium catalysts and has produced alpha-allylated products.

Research has been conducted on the bicyclic cyclopentenones. Results indicate that the complex produced via the dicobalt octacarbonyl and chiral bisphosphite reaction can serve as the intramolecular asymmetric Pauson-Khand reaction's catalyst.

Research has been conducted on the palladium-catalyzed cross-conjugated silyl enol ether cycloalkenylation. The role of the catalysts, solvents and substituent groups in this cycloalkenylation has been investigated and the results indicate that the catalytic reaction proceeds smoothly.

Research has been conducted on the use of the rhodium catalysts and organoboron reagents in the reactions. The mechanism establishing the catalytic cycle of the rhodium-catalyzed 1,4-addition of organoboronin acid has been developed and is described.

Research has been conducted on the delta-substituted allylic acetates. The substitutions of these acetates with the Grignard reagents and copper catalysts has been investigated and the results indicate that these substitutions occur with high diastereoselectivities.

Research has been conducted on the Chinese medicine natural product, (S)-(+)-imperanene. The synthesis of this compound has been carried out from the cinnamic acid by the enantioselective carbon-hydrogen insertion from the diazoacetate via the use of the chiral dirhodium(II) carboxamidate catalyst and the details are described.

Research has been conducted on the 1-methyl-2-methyleneacenaphthenes which bear a variable substituent at the 1-position. The synthesis of these compounds and their hydrogenation in ethanol in assessing substituent's haptophilicity have been carried out and are discussed.

Research has been conducted on the sulfoxides. The description of the method developed for the sulfoxide deoxygenation to their corresponding sulfides at room temperature is presented.

Research has been conducted on 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) which catalyzes aromatic amino acid biosynthesis's first step in prokaryotes, fungi and plants. The cloning of the complete gene defined by the small genomic DNA fragment and the determination of its evolutionary relationship to the DAHP synthases have been carried out and the details are reported.

Research has been conducted on the butadiene. The butadiene's cyclodimerization mechanism has been investigated via the use of the generic catalyst explored by the gradient-corrected density functional method and the results are described.

Research has been conducted on the cyclic esters' ring-opening polymerization. The structural characterization of the iron(III)-alkoxide complexes and the comparative studies of the compounds' behavior have been carried out and are described.