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By doping 1,1-dimethyl-2,5-bis(N,N-dimethylaminophenyl)-3,4-diphenylsilole (silole-A) in poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), an improved photoconductive characteristics was observed for a single layer organic device fabricated by a spin-coating process. A maximum external quantum efficiency (EQE) was 8.9% at -20 MV/m when the ratio of silole-A:F8BT was 75 mol%. The EQE of the reference device with F8BT only was 0.06%, and the highest EQE was approximately 160 times higher than that of the reference device. In addition, the photoluminescence (PL) quantum efficiency of the silole-A:F8BT neat film was lower than those of silole-A and F8BT neat films. The lower PL quantum efficiency indicates that the photo-induced carriers efficiently dislocate in the organic layer, resulting in the high EQE of organic photoconductive device. [ABSTRACT FROM AUTHOR]

Preparation of photo-responsive carbosilane dendrimers bearing 4-phenylazobenzonitrile units on their molecular surface has been accomplished, and their both photo and thermal behaviors have also been characterized. These functional dendrimers suggest that the apparent molecular sizes of the cis-isomers are smaller than those of the corresponding trans-isomers, since the molecular diameter of these dendrimers would be shorter on the basis of trans→cis photo-isomerization of azobenzene. [ABSTRACT FROM AUTHOR]

We have observed an electroluminescence (EL) of perylene (blue), coumarin 6 (green), 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran and/or zinc tetra-phenylporphyrin (red) via an efficient intermolecular energy transfer from poly (m-hexoxyphenyl)phenylsilane (PHPPS). The EL device has a single layer which was prepared simply by spin coating the mixed solution of PHPPS and energy-matched dye molecules. The EL spectrum can easily be tailored by intermixing appropriate dye molecules in the solution. We demonstrated a white EL from the mixture of PHPPS and these four dyes. The combination of a conducting polysilane and energy-matched dye molecules enabled us to open a field of Si-based EL devices through wet processes. [ABSTRACT FROM AUTHOR]

Poly[9,9-dioctylfluorenyl-2,7-diyl]-co-1,4-benzo-(2,1,3)-thiadiazole (F8BT) is one of the suitable materials for color-selective organic photoconductive devices owing to its high carrier mobility and absorption coefficient against only the blue light. We investigated a mixing method using a silole derivative, 1,1-dimethyl-2,3,4,5-tetraphenylsilole (DMTPS), in F8BT to improve the ratio between photocurrent and dark current (ON/OFF ratio), which is an important parameter for practical organic photoconductive devices. These organic materials can be coated by a solution process, which leads us to realize a low fabrication cost and a large device area in the future. By adding DMTPS into F8BT, the maximum improvement in ON/OFF ratio of 5 times was achieved compared with the reference device with F8BT only; however, the external quantum efficiency was independent of the concentration of DMTPS less than 50 wt %. In addition, the wavelength selectivity of DMTPS:F8BT in the visible wavelength region was almost the same as that of F8BT only. This result indicates that the DMTPS:F8BT layer can absorb only the blue light, indicating the possibility of a color separation without a prism for high-resolution cameras by combining the green- and red-sensitive devices. [ABSTRACT FROM AUTHOR]

New chiral dopants for nematic liquid crystals, containing a (S)-3,3′-(4H,4′H)-spirobi(2H-naphtho[1,2-b]pyran) skeleton, were synthesized and their helical twisting powers (HTP) were evaluated. A chiral dopant with two terphenyl structures showed the highest molar HTP value of 50.3 μm-1 mol-1 kg. [ABSTRACT FROM AUTHOR]

The synthesis and optical resolution of 3,3'-(4H,4'H)-spirobi(2H-naphtho[1,2-b]pyran)-6,6'-dicarboxylic acid were successfully accomplished. The formation of the spiro skeleton and the bromination of the aromatic ring were easily achieved in the presence of bromine. Optical resolution was achieved by amidation with L-valinol (2-amino-3-methyl-1-butanol). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Sugar-amino acid hybrid monomers were prepared. • Assembly of the monomers was accomplished by radical polymerization. • Affinities of the polymers against Stxs were examined. • High cluster-type polymers showed higher affinity than low cluster-type polymers. Abstract Synthetic assembly of sugar moieties and amino acids in order to create "sugar-amino acid hybrid polymers" was accomplished by means of simple radical polymerization of carbohydrate monomers having an amino acid-modified polymerizable aglycon. Amines derived from globotriaoside and lactoside as glycoepitopes were condensed with known carbobenzyloxy derivatives, including Z-Gly, Z- l -Ala and Z-β-Ala, which had appropriate spacer ability and a chiral center to afford fully protected sugar-amino acid hybrid compounds in good yields. After deprotection followed by acryloylation, the water-soluble glycomonomers were polymerized with or without acrylamide in the presence of a radical initiator in water to give corresponding copolymers and homopolymers, which were shown by SEC analysis to have high molecular weights. Evaluation of the biological activities of the glycopolymers against Shiga toxins (Stxs) was carried out, and the results suggested that glycopolymers having highly clustered globotriaosyl residues had high affinity against Stx2 (K D = 2.7∼4.0 µM) even though other glycopolymers did not show any affinity or showed very weak binding affinity. When Stx1 was used for the same assay, all of the glycopolymers having globotriaosyl residues showed high affinity (K D = 0.30∼1.74 µM). Interestingly, couple of glycopolymers having lactosyl moieties had weaker binding affinity against Stx1. In addition, when cytotoxicity assays were carried out for both Stxs, glycopolymers having highly clustered globotriaosyl residues showed higher affinity than that of the copolymers, and only highly clustered-type glycopolymers displayed neutralization potency against Stx2. [ABSTRACT FROM AUTHOR]

Abstract: Synthetic construction of fucosyl chitobiose [GlcNAcβ1→4(Fucα1→3)GlcNAc] as an allergy-associated carbohydrate epitope was accomplished from three building blocks. The trisaccharidic unit was further transformed into a carbohydrate monomer and polymerization of the glycomonomer proceeded smoothly to provide a series of glycopolymers having various carbohydrate densities. In addition to the organic syntheses, biological evaluations of the glycomonomer and the polymers were carried out and sugar-clustering effects were observed. [Copyright &y& Elsevier]

Abstract: A new compound having a 2,3,4,5-tetraphenylsilole derivative on the center silicon of Dumbbell(1)6Gb3; Silole-Dumbbell(1)6Gb3 (1) was previously reported. It was found that 1 exhibited strongly increased fluorescence both in water and in a 96% acetone/water mixed solvent. The physical behavior of 1 in water and in the 96% acetone/water mixed solvent was investigated, and analyses including fluorescence quantum yields, dynamic-light-scattering (DLS), atomic-force-microscopy (AFM), and fluorescence microscopy were carried out. It was clarified that 1 dynamically formed different types of aggregates in water and in higher acetone concentrations to yield high aggregation-induced emission (AIE) effects due to the formation of micelle-like particles in water and inversion-type micelles in the acetone/water mixed solvent, respectively. [Copyright &y& Elsevier]

Abstract: A glycocluster peripherally functionalized with a lactose (Lac: Galβ1→4Glcβ1–) derivative possessing a silole moiety as a luminophore was synthesized. The photoluminescence spectrum of the glycocluster showed extremely strong emission at 474nm and the absolute quantum yield was estimated to be 92% in distilled water. The emission intensity was decreased by increasing the amount of peanut agglutinin (PNA), a lactose-binding lectin, and plots of the relative fluorescence intensity revealed a decline of 95% in emission intensity. Fluorescence quenching of the glycocluster upon mixing with PNA could be easily observed by the naked eye under UV irradiation, whereas no distinct change in fluorescence properties of the glycocluster was observed when wheat germ agglutinin (WGA) was employed. [Copyright &y& Elsevier]