Synthesis of alpha-heteroarylpropanoic acid via asymmetric hydroformylation catalyzed by Rh(I)-(R,S)-BINAPHOS and the subsequent oxidation

The asymmetric hydroformylation of vinyl heteroarenes (vinylfurans and vinylthiophenes) was investigated by using Rh(I)-BINAPHOS derivatives as a catalyst. The hydroformylation of vinylthiophenes 1 gave the corresponding branched aldehydes 2 with high enantiopurities as major products. Oxidation of the aldehydes 2 successfully afforded alpha-heteroarylpropanoic acids 4 in good yields. In addition, the aldehydes 2 were reduced to alcohols 5 without loss of enantiomeric excess.     

Chiral Bis(oxazoline) Ruthenium Complexes with Bipyridyl‐Type N‐Heteroaromatics: Comparative Stereochemical and Photochemical Characterization of their Λ‐ and Δ‐Diastereomeric Geminate Isomers

Diastereomeric geminate pairs of chiral bis(2‐oxazoline) ruthenium complexes with bipyridyl‐type N‐heteroaromatics, Λ‐ and Δ‐[Ru(L‐ L)₂(iPr‐biox)]²⁺ (iPr‐biox=(4S,4′S)‐4,4′‐diisopropyl‐2,2′‐bis(2‐oxazoline); L‐ L=2,2′‐bipyridyl (bpy) for 1 Λ and 1 Δ, 4,4′‐dimethyl‐2,2′‐bipyridyl (dmbpy) for 2 Λ and 2 Δ, and 1,10‐phenanthroline (phen) for 3 Λ and 3 Δ), were separated as BF₄ and PF₆ salts and were subjected to the comparative studies of their stereochemical and photochemical characterization. DFT calculations of 1 Λ and 1 Δ electronic configurations for the lowest triplet excited state revealed that their MO‐149 (HOMO) and MO‐150 (lower SOMO) characters are interchanged between them and that the phosphorescence‐emissive states are an admixture of a Ru‐to‐biox charge‐transfer state and an intraligand excited state within the iPr‐biox. Furthermore, photoluminescence properties of the two Λ,Δ‐diastereomeric series are discussed with reference to [Ru(bpy)₃]²⁺.     

Glycosyl sulfonium ions as storable intermediates for glycosylations

Glycosyl sulfonium ions, which serve as persistent glycosyl cation equivalents, were prepared by the addition of diorganosulfides to an electrochemically generated glycosyl triflate. Low-temperature and variable-temperature NMR studies were performed to reveal the structure, stability, and reactivity of glycosyl sulfonium ions. The glycosyl sulfonium ions could be used as storable intermediates for reactions with various glycosyl acceptors including thioglycosides to give the corresponding disaccharides.     

Recent progress in controlling photophysical processes of donor–acceptor arrays involving perylene diimides and boron-dipyrromethenes

This review summarizes recent studies concerning photophysical processes of donor–acceptor arrays involving perylene diimides and boron-dipyrromethenes (BODIPYs), and discusses fundamental photophysical properties, electron transfer in donor–acceptor arrays in solution and in aggregate systems, and applications to solar cells and sensors in biological systems (for BODIPYs). These compounds are generally characterized as fluorescent dyes and exhibit poor efficiency in intersystem crossing in direct excitation. However, a few studies have reported that the intersystem crossing is strongly induced by the following methodologies: presence of heavy atoms including metal ions; presence of radical substituents; charge recombination of the generated charge separated states; and hyperfine interactions in long-separated radical pairs. These methodologies are useful to selectively generate locally excited triplet states or charge separated states with minimal loss of deactivation to the singlet ground states. In this review, these methodologies are also introduced and discussed.     

Boron‐ and Phosphorus‐Hyperdoped Silicon Nanocrystals

Hyperdoping silicon nanocrystals (Si NCs) to a concentration exceeding the solubility limit of a dopant may enable their novel applications. Here, the successful hyperdoping of Si NCs with boron (B) and phosphorus (P) is demonstrated, which are the most important dopants for Si. Despite the hyperdoping, the diamond structure of Si NCs is hardly modified. There are both electrically active B and P in hyperdoped Si NCs. It is proposed that the hyperdoping is made possible mainly by the kinetics in the nonthermal plasma synthesis of Si NCs. Collision between Si NCs and B or P atoms and the binding energy of B or P at the NC surface are critical to the understanding on the differences in the doping efficiency and dopant distribution between B and P. B‐hyperdoping‐induced tensile stress needs to be taken into account in the investigation on the doping and oxidation of Si NCs.     

A Combined 6π-Azaelectrocyclization/Staudinger Approach to Protein and Cell Engineering: Noninvasive Tumor Targeting by N-Glycan-Engineered Lymphocytes

A Combined 6π-Azaelectrocyclization/Staudinger Approach to Protein and Cell Engineering: Noninvasive Tumor Targeting by N-Glycan-Engineered Lymphocytes

All authors

Katsunori Tanaka, Kaori Minami, Tsuyoshi Tahara, Eric R. O. Siwu, Koichi Koyama, Satoshi Nozaki, Hirotaka Onoe, Yasuyoshi Watanabe & Koichi Fukase

https://doi.org/10.1080/07328303.2010.483042

Published online:

02 June 2010

Graphical Abstract     

459.

Orange and yellow crystals of copper(I) complexes bearing 8-(diphenylphosphino)quinoline: a pair of distortion isomers of an intrinsic tetrahedral complex     

Suzuki T  Yamaguchi H  Hashimoto A  Nozaki K  Doi M  Inazumi N  Ikeda N  Kawata S  Kojima M  Takagi HD 《Inorganic chemistry》2011,50(9):3981-3987

The tetrafluoroborate salt of bis{8-(diphenylphosphino)quinoline}copper(I), [Cu(Ph(2)Pqn)(2)]BF(4), afforded orange prismatic (2O) or yellow columnar (2Y) crystals, dependent on the solvent and concentration of the recrystallization solution used. X-ray analysis revealed that crystals of 2O and 2Y had the same composition and exhibited different crystal systems: 2O was triclinic, with space group P ?1 and Z = 2, and 2Y was monoclinic with space group P2(1)/c and Z = 4. In these crystals, the tetrahedral copper(I) complex exhibited a strong "rocking distortion" toward a trigonal pyramidal coordination geometry (by a slide translation of one of the unsymmetrical bidentate chelating ligands along the tetrahedral edge). In addition, both the 2O and 2Y complexes showed a "flattening distortion", meaning that the dihedral angle between the two chelate planes were off-perpendicular and oriented toward opposite directions, which resulted in a pair of distortion isomers: syn clinal (sc: 2O) and anti clinal (ac: 2Y). (31)P CP-MAS NMR spectroscopy indicated that 2O and 2Y could be distinguished. Both isomers exhibited inequivalent P atoms, but a larger difference in chemical shift was observed in 2Y. TD-DFT calculations reproduced the difference in spectra between the orange- and yellow-colored complexes, which originated from metal-to-ligand charge-transfer transitions.     

460.

CdS-ZnO composite nanorods: Synthesis, characterization and application for photocatalytic degradation of 3,4-dihydroxy benzoic acid     

J. Nayak  S.N. Sahu  S. Nozaki 《Applied Surface Science》2008,254(22):7215-7218

Well-aligned arrays of CdS-ZnO composite nanorods were grown on indium tin oxide substrates. ZnO nanorods, deposited by a low temperature aqueous chemical growth technique, were dip coated with CdS. The CdS-ZnO nanorods were polycrystalline as confirmed from the low angle X-rays diffraction study. Photon to current conversion efficiency of CdS-ZnO composite nanorod was observed to be higher than that of CdS. In the micro-Raman spectrum, we observed longitudinal optical modes of CdS and ZnO showing their co-existence. The appealing application of CdS-ZnO nanorod as a visible photocatalyst was demonstrated and the possible mechanism was discussed.     

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Orange and yellow crystals of copper(I) complexes bearing 8-(diphenylphosphino)quinoline: a pair of distortion isomers of an intrinsic tetrahedral complex

The tetrafluoroborate salt of bis{8-(diphenylphosphino)quinoline}copper(I), [Cu(Ph(2)Pqn)(2)]BF(4), afforded orange prismatic (2O) or yellow columnar (2Y) crystals, dependent on the solvent and concentration of the recrystallization solution used. X-ray analysis revealed that crystals of 2O and 2Y had the same composition and exhibited different crystal systems: 2O was triclinic, with space group P ?1 and Z = 2, and 2Y was monoclinic with space group P2(1)/c and Z = 4. In these crystals, the tetrahedral copper(I) complex exhibited a strong "rocking distortion" toward a trigonal pyramidal coordination geometry (by a slide translation of one of the unsymmetrical bidentate chelating ligands along the tetrahedral edge). In addition, both the 2O and 2Y complexes showed a "flattening distortion", meaning that the dihedral angle between the two chelate planes were off-perpendicular and oriented toward opposite directions, which resulted in a pair of distortion isomers: syn clinal (sc: 2O) and anti clinal (ac: 2Y). (31)P CP-MAS NMR spectroscopy indicated that 2O and 2Y could be distinguished. Both isomers exhibited inequivalent P atoms, but a larger difference in chemical shift was observed in 2Y. TD-DFT calculations reproduced the difference in spectra between the orange- and yellow-colored complexes, which originated from metal-to-ligand charge-transfer transitions.     

CdS-ZnO composite nanorods: Synthesis, characterization and application for photocatalytic degradation of 3,4-dihydroxy benzoic acid

Well-aligned arrays of CdS-ZnO composite nanorods were grown on indium tin oxide substrates. ZnO nanorods, deposited by a low temperature aqueous chemical growth technique, were dip coated with CdS. The CdS-ZnO nanorods were polycrystalline as confirmed from the low angle X-rays diffraction study. Photon to current conversion efficiency of CdS-ZnO composite nanorod was observed to be higher than that of CdS. In the micro-Raman spectrum, we observed longitudinal optical modes of CdS and ZnO showing their co-existence. The appealing application of CdS-ZnO nanorod as a visible photocatalyst was demonstrated and the possible mechanism was discussed.