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The synthesis and crystal structure of the stable and water-soluble tantalum peroxo-lactate complex with acid (ammonium tetralactatodiperoxo-[mu]-oxo-ditantalate(V)), [(N[H.sub.4]).sub.4][T[a.sub.2][([C.sub.2][H.sub.4][O.sub.3]).sub.4][([O.sub.2]).sub.2]O].3[H.sub.2]O is presented. The solution of the tantalum complex was successfully applied for the synthesis of two photocatalytic materials, NaTa[O.sub.3] and S[r.sub.2]T[a.sub.2][O.sub.7].

The cis-dioxo-molybdenum(VI) complexes with new aliphatic dithiolene ligands and mono-oxo-molybdenum(IV) complexes are prepared and investigated. The oxygen atoms of the cis-Mo(super VI)O2 cores are relatively nucleophilic and hence these complexes are unstable in protic solvents and protonation might occur to produce Mo(super VI)O(OH), as observed with the oxidized state of arsenite oxidase.

A study is conducted to synthesize N-(2-(5-cyanopyridyl) cyclen 10(L5) and N-(2-pyridyl) cyclen 11(16) in order to control TICT in aqueous solution utilizing the potent binding properties of cyclen. Chelation-controlled TICT with a considerable shift of emission wavelength may provide new methodologies for designing novel fluorescence sensors for metal ions and biologically relevant anions in aqueous solution.

A novel, mild method is described to synthesize 6-methylidene penem compounds. This process provides a useful variation of C-C bond formation method for penem derivatives and also serves as a practical synthetic method to prepare 6-exomethylenepenem derivatives without racemization at the C5 position.

Catalytic asymmetric aldol reactions in aqueous media have been developed using Pf (OTf) (sub 3) and chiral bis-pyridino-18-crown-6 1. In the asymmetric aldol reaction using rare earth metal triflates (RE (Otf)(sub 3)) and 1, slight changes in the ionic diameters of the metal cations greatly affected the diastereo and enantioselectivities of the products.

The synthesis of a hydroxypyridone-bearing nucleoside and the incorporation of a neutral Cu (super 2+)-mediated base pair of hydroxypyridone nucleobases (H-Cu-H) in a DNA duplex are reported. Monitoring temperature dependence of UV-absorption changes verified that a Cu (super 2+) mediated base pair is stoichiometrically formed inside the duplex and dissociates upon thermal denaturation at elevated temperature.

Research has been conducted on the salts. Results indicate that the charge-transfer ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide charge-transfer salts containing FeBr (sub)4 (super)- and GaBr (sub)4 (super)- counteranions have been obtained as needle crystals with almost identical structures.

Research has been conducted on the carbonic anhydrase and carboxypeptidase A. The intrinsic recognition of carboxamides by zinc(II) in these carbonic anhydrase and carboxypeptidase A has been carried out via the synthesis of the zinc(II)-carboxamide-appended cyclen complexes (cyclen= 1,4,7,10-tetraazacyclododecane) and the results are reported.

The multiple bonding between multinuclear zinc(II)-1,4,7,10-tetraazacyclododecane (cyclen, a 12-membered tetraamine) complexes and multidentate ligands is an effective method for constructing supramolecular complexes having well defined and distinct structures in aqueous solution. Herein we present examples of supramolecular [D.sub.3h] prisms formed by self-assembly of linearly dimeric or trimeric zinc(II)-cyclen complexes with a potentially trianionic [C.sub.3] subunit trithiocyanuric acid ([TCA.sup.3-]), wherein [Zn.sup.2+]--[S.sup.-] or [Zn.sup.2+]-[N.sup.-] coordination bonds and hydrogen bonds are responsible for stability of the multicomponent architectures in aqueous solution at neutral pH.

Research has been conducted on the alkaloid cephalocyclidin A isolated from Cephalotaxus harringtonia var. nana fruits. The structure of this alkaloid with the fused-pentacyclic skeleton and six-consecutive asymmetric centers has been investigated and the results are described.

Research has been conducted on the quasi-one-dimensional halogen-bridged Cu (super)II- Pt (super)IV mixed-metal complexes of the form [Cu(chxn) (sub)2][PtX (sub)2 (chxn) (sub)2]X (sub)4, where chxn= 1R,2R-diminocyclohexane and X is Cl or Br. The synthesis of these complexes has been carried out and the crystal structures of the compounds determined by the single-crystal X-ray diffraction have been investigated.

Eight highly modified Daphniphyllum alkaloids with unprecedented fused hexa- or pentacyclic skeletons, daphnicyclidins A-H, were isolated from the stems of Daphniphyllum humile and D. teijsmanni, and their structures were analyzed on the basis of spectroscopic data and chemical means. The stereochemistry was elucidated by combination of NOESY correlations, X-ray crystallographic data and CD analyses.

The synthesis, structure and reactions of (acylimino)triaryl-lambda(super 5)-bismuthanes and a comparative study of the structure and reactivity of a series of (acylimino)pnictoranes is given. The unique reactivities of (acylimino)triaryl-lambda(super 5)-bismuthanes demonstrate their potential utility in organic synthesis.

It has been possible to develop a mild and practical enantioselective fluorination reaction using widely available cinchona alkaloid derivatives linked with Selectfluor. Several cyclic and acyclic carbonyl compounds were fluorinated enantioselectively to produce the corresponding alpha-fluoro compounds.

Results show that the titanium complex of the ammonium citratoperoxotitanate exhibits extraordinary stability against hydrolysis due to tight coordination of titanium in the molecule. The aqueous solution is stable over a broad range of pH.

Self-assembly of a tris(Zn2+-cyclen) complex resulted in isolation of two new three-dimensional supermolecules with closed hollow frameworks.

The article discusses the synthesis of sterically hindered tris-pyridyl methane ligands. The mechanism for their hydroxylation in the reaction with CuBr (sub)2 in MeOH under air is analyzed.

Research has been conducted on the asymmetric synthesis of (+)-dihydrokawain-5-ol. Experiments with furan ring degradation in the furyl alcohol are discussed.

A study of the onium transfer reaction of alkenyl(phenyl)iodonium tetrafluoroborates to prepare group 15 1-alkenyl(triphenyl)onium (P, As, Sb) tetrafluoroborates is presented. Results demonstrate that reaction involves base-induced reductive alpha-elimination of the iodonium salts.

A study was conducted to investigate the role of zinc(II) in aldolase-catalyzing reversible stereospecific aldol condensation. No clear chemical elucidation for the reversible mechanism of the aldol reaction particularly the reaction mechanism of class II aldolases has been experimentally established to date. The experiment reports on a new chemical model for the substrate-bound class II aldolases.