Search

The effects of anchoring groups on electron injection from adsorbate to nanocrystalline thin films were investigated by comparisons injection kinetics through carboxylate versus phosphonate groups to Ti[O.sub.2] and Sn[O.sub.2]. The anchoring groups were shown to have negligible effects on the energetics of relevant orbitals in the Re complexes.

The dependence of Re(L(sub p))(CO)3Cl (or ReClP) [Lp = 2,2'-bipyridine-4,4'-bis-CH2PO(OH)2] and Re(LA)(CO)3Cl (or ReClA) [L(sub A)=2,2'-bipyridine-4,4'-bis-CH2COOH] sensitized TiO2 and ReClP sensitized SnO2 nanocrystalline thin films is examined. Results suggests that the observed pH-dependent electron transfer rate can be qualitatively accounted for by considering the change of density of electron-accepting states caused by the pH-dependent conduction band edge position.

Research has been conducted on the macrocyclic polyamine binuclear palladium(II) complexes. The use of these complexes in constructing specially shaped molecules is described.

A research on the ways by which copper phenanthroline bind to beta-form DNA involved the varying of the composition of the DNA, and the use of poly (dG-dC).poly (dG-dC), M. lysodeikticus DNA, salmon testes DNA and poly (dA-dT).poly (dA-dT) as hosts. The dmp complex bound externally in a solvent accessible site was discovered. The presence of DNA causes Cu(bcp)2+ to be emissive. Hence, the metal center is accessible to the solvent.

The RNA-binding interactions of the Cu(I) phenanthroline complexes, Cu(dmp)2(super +) and Cu(bcp)2(super +), where dmp = 2,9-dimethyl- 1,10- phenanthroline; bcp = 2,9-dimethyl-4,7- diphenyl- 1,10- phenanthroline, are elucidated. Spectroscopic studies show that Cu(dmp)2+ binds to RNa by surface association. The interaction of Cu(bcp)2(super +) with RNA depends on the nucleotide-copper ratio. The aggregated form of Cu(bcp)2(super +) binds to RNA at lower nucleotide-copper ratio while the aggregate split up at higher ratio although Cu(bcp)2(super +) remains bound to RNA because of continued inhibition of solvent-induced emission quenching.

13C NMR coupled relaxation techniques were used to measure the relaxation of different magnetization modes in the synthesized isotopic decanols 13C labeled at 1, 5 and 9 positons. Comparison of the correlation times for the 13CH2 group at varying positions and solvents revealed that the formation of a hydrogen bond between 1-decanol and the solvents influences the movement of neighboring chain segments. Stochastic dynamic studies support the use of ordinary Langevin equations for the description of the solute relaxationwithout relaxation modes with the ability to bind with the solute chain.

A convenient route is developed for preparing various charged tetracyclic isoquinolizinium hexafluorostilbates by using AgSb[F.sub.6]/AuCl(P[Ph.sub.3]) for the intramolecular addition of amine to alkyne. The process is tolerant of a variety of functional groups and has broadened the diversity of substrates with the use of 8-substituted tetracyclic isoquinolizinium salts.

A synthesis method is described by using chlorotrimethylsilane as the activator to brominates the Ni(II) complex of the [beta]-alanine SchiffEs base [[beta]-AlaNi(II)PABA] and it is developed to prepare [beta]-amino acids. The procedure has involved a Suzuki coupling reaction between boric acids and bromoenone and this is the first report on the application of the Ni(II) complex [[beta]-AlaNi(II)PABA] for producing [alpha]-aryl-/heteroaryl-substituted [beta]-amino acids.

The design and synthesis of a novel phosphodiester receptor 1-(2-guanidinoethyl)-4-(2-hdyroxyethyl)1-1,4,7-triazacyclononane hydrochloride and the studies of its DNA cleavage activity is reported. Kinetic data of DNA cleavage promoted by 1-(2-guanidinoethyl)-4-(2-hdyroxyethyl)1-1,4,7-triazacyclononane hydrochloride fit to a Michaelis-Menten-type equation with [K.sub.max] of 0.160 [h.sup.-1] giving [10.sup.7]-fold rate acceleration over uncatalyzed DNA.

Smad3 is phosphorylated by ERK MAP kinase upon EGF treatment. The ERK phosphorylation sites to Ser 207, Ser 203, and Thr 178 in Smad3 is mapped and it is shown that mutation of the ERK phosphorylation sites increases the ability of Smad3 to stimulate a Smad target gene, suggesting that ERK phosphorylation inhibits Smad3 activity.

Potential step measurement is performed on single beads of spherical nickel hydroxide to determine the proton diffusion coefficient (D) and concentration of the effective proton vacancies (C). The semi-infinite diffusion equation for the initial stage and the finite diffusion equation for the long-term of the current response to potential step are used for deducing the D and C values.

Multisegment Pt-Ni nanorods were prepared by sequential electrodeposition of Pt and Ni into nanoporous anodic aluminum oxide membranes and characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The overall rod length and the total Pt segment length for different nanorods were kept at 1.6 (mu)m and 530 nm respectively by controlling conditions used in the galvanostatic electrodeposition.

Realizing combination drugs at a molecular level via drug-drug cocrystallization opens a new pathway for effective therapeutic hybrids. A "drug-bridge-drug" strategy is developed to cocrystallize two first-line antitubercular drugs isoniazid and pyrazinamide using fumaric acid as the bridge, overcoming the issue of hardly cocrystallizing two different drugs. The first example of ternary cocrystal with combination drugs exhibits optimized formulation capacity and in vitro/vivo synergistic effects, which provides a new insight into antituberculosis combination drugs. [ABSTRACT FROM AUTHOR]

We have investigated the gas-phase production of isoquinoline by performing collisional activation on benzalaminoacetal, the first intermediate in the classic solution-phase Pomeranz--Fritsch synthesis of isoquinoline. We have elucidated the reaction pathways in the gas phase using tandem mass spectrometry. Unlike the corresponding condensed-phase reaction, where catalytic proton exchange between intermediate(s) and solvent (Brønsted--Lowry base) is known to drive the reaction, the gas-phase reaction follows the "mobile proton model" to form the products via a number of intermediates, some the same as in their condensed-phase counterparts. Energy-resolved mass spectrometry, deuterium labeling experiments, and theoretical calculations (B3LYP/6-31G**) identified 27 different reaction routes in the gas phase, forming a complex interlinked reaction network. The experimental measurements and theoretical calculations confirm the proton hopping onto different basic sites of the precursors and intermediates to transform them ultimately into isoquinoline. [ABSTRACT FROM AUTHOR]