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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.

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.

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.

We computationally study the chiral transition process of the α-Ala molecule under confined different sizes of armchair SWBNNTs to explore the confinement effect. We find that the influence of a confinement environment (in armchair SWBNNTs) on the α-Ala molecule would lead to different reaction pathways. Meanwhile, the preferred reaction pathway is also different in various sizes of armchair SWBNNTs, and their energy barriers for the rate-limiting step decrease rapidly with the decreasing of the diameters of the nanotubes. It is obvious that significant decrease of the chiral transition energy barrier occurs compared with the isolated α-Ala molecule chirality conversion mechanism, by ∼15.6 kcal mol-1, highlighting the improvement in the activity the enantiomers of α-Ala molecule. We concluded that the confinement environment has a significant impact at the nanoscale on the enantiomer transformation process of the chiral molecule. [ABSTRACT FROM AUTHOR]

Hydroxyacetone (CH3C(O)CH2OH) is observed as a stable end product from reactions of the (CH3)2COO Criegee intermediate, acetone oxide, in a flow tube coupled with multiplexed photoionization mass spectrometer detection. In the experiment, the isomers at m/z = 74 are distinguished by their different photoionization spectra and reaction times. Hydroxyacetone is observed as a persistent signal at longer reaction times at a higher photoionization threshold of ca. 9.7 eV than Criegee intermediate and definitively identified by comparison with the known photoionization spectrum. Complementary electronic structure calculations reveal multiple possible reaction pathways for hydroxyacetone formation, including unimolecular isomerization via hydrogen atom transfer and -OH group migration as well as self-reaction of Criegee intermediates. Varying the concentration of Criegee intermediates suggests contributions from both unimolecular and self-reaction pathways to hydroxyacetone. The hydroxyacetone end product can provide an effective, stable marker for the production of transient Criegee intermediates in future studies of alkene ozonolysis. [ABSTRACT FROM AUTHOR]

A novelseries of donor–acceptor star-shaped conjugatedmacroelectrolytes (CMEs), denoted as 4FTs, including anionic carboxylicacid sodium groups (4FNaT), neutral diethanolamine groups (4FNOHT),and cationic ammonium groups (4FNBrT), were designed, synthesized,and explored as an excellent platform to investigate the impact ofvarious polar pendent groups on self-assembly behaviors. The resultingCMEs with donor–acceptor star-shaped architectures exhibiteddistinct light-harvesting properties. The interactions between 4FTsand TrNBr, a star-shaped monodisperse CME grafted with cationic quaternaryammonium side chains, were investigated in H2O and CH3OH using steady-state, time-resolved fluorescence, dynamiclight scattering (DLS), and transmission electron microscopy (TEM).Highly favored energy transfer has been proven by the excellent spectraloverlap between TrNBr fluorescence and 4FTs absorptions which canbe tuned by adjusting the pendent polar groups and solvents. It issuggested that self-assembled structures are formed between TrNBrand 4FNaT, while there is no obvious change for TrNBr/4FNOHT and TrNBr/4FNBrTin both H2O and CH3OH at low concentrations(<10–6M). This result is confirmed by the changeof the TrNBr and 4FTs fluorescence properties and the time-resolvedfluorescence data. The overall results manifest that at low concentrationsthe self-assembly between TrNBr and 4FTs is dominated by the electrostaticinteractions. This study suggests that the functionalization of pendentpolar groups of star-shaped CMEs has proven to be effective to modulatethe self-assembly behaviors in dilute solutions and thus provide astrategy to further manage the optoelectronic properties. [ABSTRACT FROM AUTHOR]

The nitrogen inversion of a N-phenyl aziridine fused to a succinimide ring is influenced by the presence of a phenyl ring in the succinimide moiety. The endo invertomer is favored, showing an unsymmetrical equilibrium in variable ¹H NMR studies. [ABSTRACT FROM AUTHOR]