Photoassisted NO reduction with NH3 over TiO2 photocatalyst

Photoassisted selective catalytic reduction of NO with ammonia (photo-SCR) at low temperature over irradiated TiO2 in a flow reactor was confirmed to proceed efficiently and the adsorbed ammonia reacted with NO under irradiation of TiO2.     

Asymmetric polymerization using C1 resources

Two examples of asymmetric alternating copolymerization, (1) the alternating copolymerization of α‐olefins (monosubstituted ethenes) with carbon monoxide and (2) the alternating copolymerization of meso‐epoxide with carbon dioxide, are described, and the meaning of chirality in polymer synthesis is emphasized. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 215–221, 2004     

Efficient routes to optically active azido-, amino-, di-azido- and di-amino-cyclitols with chiro- and allo-configuration from myo-inositol

Efficient routes to hitherto unknown 1d-2,5-di-azido-di-deoxy-allo-inositol, 1d-2,5-di-amino-di-deoxy-allo-inositol, 1l-1-azido-1-deoxy-chiro-inositol and 1l-1-amino-1-deoxy-chiro-inositol were developed by using cheaply available myo-inositol as the starting material. Preliminary investigations on the enzyme inhibitory properties were done. The methodology reported is amenable to gram scale synthesis and thus can find application in natural product synthesis.     

NMR and MO Studies on the Molecular Structure of a Fluoranthene-Benzene Complex

Summary. Fluoranthene (FA) forms a 1:1 van der Waals complex with benzene in cyclohexane. The ¹H NMR spectrum of this complex shows that the FA moiety in the complex state has five kinds of hydrogen atoms and that the ¹H NMR peaks assigned to the protons attached to the naphthalene skeleton are largely shifted to higher magnetic field on complex formation with benzene. These observations indicate that the complex takes the structure of C_S symmetry, in which the benzene molecule mainly interacts with the electronic system localized on the naphthalene moiety of FA. The present ab initio calculations reproduce well the ¹H NMR spectral shifts mentioned above and the experimentally predicted C_S structure of the complex. According to the PPP calculations for the electronic absorption spectral changes on the complex formation, the FA-benzene complex is considered to take a sandwich type structure.     

Theoretical studies on electronic states of Rh-C60. Possibility of a room-temperature organic ferromagnet

A possible mechanism for a ferromagnetic interaction in the rhombic (Rh) form of C60 (Rh-C60) is suggested on the basis of theoretical studies in relation to cage distortion of the C60 unit in the polymerized 2D-plane. Band structure calculations on Rh-C60 show that cage distortion leads to competition between diamagnetic and ferromagnetic states,which give rise to the possibility of thermally populating the ferromagnetic state.     

Esterolytic activity of imidazole-containing polymers. Synthesis and characterization of copoly[1-alkyl-4- or 5-vinylimidazole/4(5)-vinylimidazole] and its catalytic activity in the hydrolysis of p-nitrophenyl acetate

The water-soluble monomers, 1-methyl-4-vinylimidazole, 1-methyl-5-vinylimidazole, 1-ethyl-5-vinylimidazole, and 1-propyl-5-vinylimidazole have been synthesized, polymerized, and copolymerized with 4(5)-vinylimidazole. The copolymers were characterized by ¹⁴C-labeling, NMR, pK_a determination and viscosity measurements. The monomer reactivity ratios determined by ¹⁴C counting are r₁ = 1.04; r₂ = 0.94 [M₁ = 4(5)-vinylimidazole, M₂ = 1-methyl-4-vinylimidazole] and r₁ = 1.01; r₂ = 0.86 [M₁ = 4(5)-vinylimidazole, M₂ = 1-methyl-5-vinylimidazole]. The esterolytic activity of the copolymers for the hydrolysis of p-nitrophenyl acetate (PNPA) at pH 7–8 in 28.5% ethanol–water was higher than that of the mixtures of homopolymers. At pH 5–6 the esterolytic activities of the copolymers and the mixtures were similar. The most efficient esterolytic activity for PNPA hydrolysis at pH 7.11 in 28.5% ethanol–water occurred for copolymers containing 75 mole % 4(5)-vinylimidazole and for copolymers containing 1-methyl-4-vinylimidazole rather than 1-methyl-5-vinylimidazole.     

Comparative studies on the analysis of glycosylation heterogeneity of sialic acid-containing glycoproteins using capillary electrophoresis

Frontal affinity chromatography is a method for quantitative analysis of biomolecular interactions. We reinforced it by incorporating various merits of a contemporary liquid chromatography system. As a model study, the interaction between an immobilized Caenorhabditis elegans galectin (LEC-6) and fluorescently labeled oligosaccharides (pyridylaminated sugars) was analyzed. LEC-6 was coupled to N-hydroxysuccinimide-activated Sepharose 4 Fast Flow (100 μm diameter), and packed into a miniature column (e.g., 10×4.0 mm, 0.126 ml). Twelve pyridylaminated oligosaccharides were applied to the column through a 2-ml sample loop, and their elution patterns were monitored by fluorescence. The volume of the elution front (V) determined graphically for each sample was compared with that obtained in the presence of an excess amount of hapten saccharide, lactose (V₀); and the dissociation constant, K_d, was calculated according to the literature [K. Kasai, Y. Oda, M. Nishikawa, S. Ishii, J. Chromatogr. 376 (1986) 33]. This system also proved to be useful for an inverse confirmation; that is, application of galectins to an immobilized glycan column (in the present case, asialofetuin was immobilized on Sepharose 4 Fast Flow), and the elution profiles were monitored by fluorescence based on tryptophan. The relative affinity of various galectins for asialofetuin could be easily compared in terms of the extent of retardation. The newly constructed system proved to be extremely versatile. It enabled rapid (analysis time 12 min/cycle) and sensitive (20 nM for pyridylaminated derivatives, and 1 μg/ml for protein) analyses of lectin–carbohydrate interactions. It should become a powerful tool for elucidation of biomolecular interactions, in particular for functional analysis of a large number of proteins that should be the essential issues of post-genome projects.