Electron paramagnetic resonance and optical absorption spectra of Cr ions in cadmium phosphate glass

EPR and optical absorption investigations of chromium doped cadmium phosphate glass are carried out. Crystal field, spin-Hamiltonian and bonding parameters are evaluated. From the results and analyses of the EPR and optical studies, the site symmetry of Cr³⁺ ion in the glass is ascribed to a distorted octahedron. The bonding parameters suggest the ionic nature of Cr³⁺ ion with the ligands.     

A fiberwise analogue of the Borsuk-Ulam theorem for sphere bundles over a 2-cell complex II

We describe a finite complex B as I-trivial if there does not exist a Z₂-map from Si−1 to S(α) for any vector bundle α over B and any integer i with i>dimα. We prove that the m-fold suspension of projective plane FP² is I-trivial if and only if m≠0,2,4 for F=C, m≠0,4 for F=H. In the case where F is the Cayley algebra, the m-fold suspension is shown to be I-trivial for every m>0.     

Mass spectrometric analysis of low molecular mass polyesters by laser desorption/ionization on porous silicon

A low molecular mass polyester was analyzed by desorption/ionization on porous silicon (DIOS) mass spectrometry. The results were compared with those of matrix-assisted laser desorption ionization (MALDI) mass spectrometry using matrixes of alpha-cyano-4-hydroxycinnamic acid (CHCA) and 10,15,20-tetrakis(pentafluorophenyl)porphyrin (F20TPP). The CHCA matrix was not suitable for characterization of low molecular mass components of the polyester because the matrix-related ions interfered with the component ions. On the other hand, the F20TPP matrix showed no interference because no matrix-related ions appeared below m/z 822. However, the solvent selection for determining optimal conditions of sample preparation was limited, because F20TPP does not dissolve readily in any of the available organic solvents. In the DIOS spectra, the polymer ions were observed at high sensitivity without a contaminating ion. No matrix is needed for DIOS spectra of low molecular mass polyesters, facilitating sample preparation and selectivity of a precursor ion in post-source decay measurements.     

Photodimerization of benzene -photochromism of layered dithiacyclophane-

A novel cage compound was obtained by irradiation of a quadruple-layered dithiacyclophane and showed thermally reverse reaction.     

Synthesis and photoinduced memory effect of poly[2-N-carbazolylethyl acrylate-co-2-(3,5-dinitrobenzoyloxy) ethyl methacrylate]

Copolymers containing an intramolecular electron donor-acceptor (EDA) complex were synthesized by free radical copolymerization of 2-N-carbazolylethyl acrylate and 2-(3,5-dinitrobenzoyloxy)ethyl methacrylate. Glass transition temperatures show a positive deviation from the weight-average values of copolymers, indicating the presence of the specific EDA interaction in copolymers in the solid state. Photoinduced “memory effect,” which is defined as the percentage of the difference of the surface potential given by corona charging before and after irradiation of light on polymer films, was 30% for the copolymer with 5 mol% of acceptor content. Memory effect increased to 70% for a 8 μm film by doping with 2 wt% of trichloroacetic acid (TCAA), and leveled off at 5 wt% of TCAA content. Memory effect was also enhanced by increasing the thickness of polymer films and irradiation time. The largest value of memory effect (85%) was obtained from the film of the copolymer with 5 mol% acceptor content doped with 1 wt% TCAA and with thickness larger than 14 μm.     

Constituents of holothuroidea.9. Isolation and structure of a new ganglioside molecular species from the sea cucumber Holothuria pervicax

A new ganglioside molecular species, HPG-7 (1) was obtained from the polar fraction of the chloroform/methanol extract of the sea cucumber, Holothuria pervicax. On the basis of chemical and spectroscopic evidence, the structure of 1 was determined, and the major component was 1-O-[alpha-L-fucopyranosyl-(1-->4)-(N-acetyl-alpha-D-neuraminosyl) - (2-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->4)-(N-acetyl -alpha-D- neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-(2S,3S,4R)-2-[(2R)-2- hydroxytetracosanoylamino]-14-methyl-hexadecane-1,3,4-triol. This is the first report on the isolation and structure elucidation of trisialo-ganglioside from sea cucumber. 1 showed neuritogenic activity toward the rat pheochromocytoma cell line, PC-12 cell.     

Three-way-output response system by electric potential: UV-vis, CD, and fluorescence spectral changes upon electrolysis of the chiral ester of tetracyanoanthraquinodimethane

The newly prepared tetracyanoanthraquinodimethane (TCNAQ) derivatives 1a,b with a chiral auxiliary are good electron acceptors and exhibit weak circular dichroism (CD) based on the absorption of TCNAQ. The twin-type electron acceptor 1c with two TCNAQ units shows larger ellipticity by exciton coupling. UV-vis, CD, and fluorescence spectra were changed drastically upon electrochemical reduction of 1c, which demonstrates the unprecedented three-way-output response system.     

Ab initio calculations of isomerization reaction of diphosphene 1-sulfide to thiadiphosphirane

Ab initio Calculations of the isomerization reaction of diphosphene 1-sulfide (2′) to thiadiphosphirane (3′) suggest that the energy barrier of the reaction in the ground state is 25 kcal/mol and that 2′ lies 21 kcal/mol above 3′, while the calculations show that there exists one local minimum on the lowest triplet energy surface.     

Importance of the Debye interaction in organic solutions: Henry's law constants for polar liquids in nonpolar solvents and vice versa

Henry's law constants have been determined for -butyrolactone (BL), ethyl acetate (EA), and 2-methyl-3-pentanol (MEP) in mixtures of iso-octane (ISO) and toluene (TOL), for BL, EA, TOL, and ISO in cinnamaldehyde (CIN) and for TOL and ISO in each other and in BL. From these data and published vapor pressures, the activity coefficients at infinite dilution and the standard molar Gibbs free energy of transfer, G ₂ ⁰ of the solutes from dilute solution in ISO to dilute solution in each solvent medium have been calculated. The different behavior patterns of BL and EA are attributed to differences in their abilities to exist in different conformations possessing different dipole moments. For polar solutes, G ₂ ⁰ decreases with increasing polarizability of the solvent and with increasing dipole moment of the solute, suggesting increased contributions from dipole-induced dipole (Debye) interactions. The sigmoidal plot of G ₂ ⁰ against the change in pair potential energy calculated from the classical expressions suggests that G ₂ ⁰ seriously underestimates the strength of the Debye interactions in comparison with the London interactions.