Preparation of RF-(VM-SiO2)n-RF/AM-Cellu Nanocomposites, and Use Thereof for the Modification of Glass and Filter Paper Surfaces: Creation of a Glass Thermoresponsive Switching Behavior and an Efficient Separation Paper Membrane.

Fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/alkyl-modified cellulose (AM-Cellu) nanocomposites [RF-(CH2-CHSiO2)n-RF/AM-Cellu; n = 2, 3; RF = CF(CF3)OC3F7] were prepared by the sol-gel reactions of the corresponding oligomer [RF-(CH2-CHSi(OMe)3)n-RF] in the presence of AM-Cellu. The nanocomposites thus obtained were applied to the surface modification of glass to exhibit a highly oleophobic/superhydrophilic characteristic on the modified surface at 20 °C. Interestingly, a temperature dependence of contact angle values of dodecane and water was observed on the modified surface at 20~70 °C, and the dodecane contact angle values were found to decrease with increasing the temperatures from 20 to 70 °C to provide from highly oleophobic to superoleophilic characteristics on the surface. On the other hand, the increase of the water contact angle values was observed with the increase in the temperatures under similar conditions to supply superhydrophilic to superhydrophobic characteristics on the modified surface. The corresponding nanocomposites were also applied to the surface modification of the filter paper under similar conditions to afford a superoleophilic/superhydrophobic characteristic on the surface. It was demonstrated that the modified filter paper is effective for the separation membrane for W/O emulsion to isolate the transparent colorless oil.

Catalyst-Free and Regioconvergent Substitution Reactions of Bromothiophenes with a BH3-Substituted Phosphide Anion.

A range of bromothiophenes reacted with lithium boranato(tert-butyl)methylphosphide in the absence of transition-metal catalysts under mild conditions to provide the same 2,5-disubstituted and 2-monosubstituted products regardless of the substitution patterns of the starting bromothiophenes.

Preparation and Surface Property of Fluoroalkyl End-Capped Vinyltrimethoxysilane Oligomer/Talc Composite-Encapsulated Organic Compounds: Application for the Separation of Oil and Water.

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R(F)-(CH2-CHSi(OMe)3)n-R(F); n = 2, 3; R(F) = CF(CF3)OC3F7 (R(F)-VM oligomer)] can undergo the sol-gel reaction in the presence of talc particles under alkaline conditions at room temperature to provide the corresponding fluorinated oligomeric silica/talc nanocomposites (RF-VM-SiO2/Talc). A variety of guest molecules such as 2-hydroxy-4-methoxybenzophenone (HMB), bisphenol A (BPA), bisphenol AF, 3-(hydroxysilyl)-1-propanesulfonic acid (THSP), and perfluoro-2-methyl-3-oxahexanoic acid (R(F)-COOH) are effectively encapsulated into the R(F)-VM-SiO2/Talc composite cores to afford the corresponding fluorinated nanocomposites-encapsulated these guest molecules. The R(F)-VM-SiO2/Talc composites encapsulated low molecular weight aromatic compounds such as HMB and BPA can exhibit a superoleophilic-superhydrophobic characteristic on the surfaces; however, the R(F)-VM-SiO2/Talc composite-encapsulated THSP and R(F)-COOH exhibit a superoleophobic-superhydrophilic characteristic on the modified surfaces. In these nanocomposites, the R(F)-VM-SiO2/Talc/THSP composites are applicable to the surface modification of polyester fabric, and the modified polyester fabric possessing a superoleophobic-superhydrophilic characteristic on the surface can be used for the membrane for oil (dodecane)/water separation. In addition, the R(F)-VM-SiO2/Talc composites-encapsulated micrometer-size controlled cross-linked polystyrene particles can be also prepared under similar conditions, and the obtained composite white-colored particle powders are applied to the packing material for the column chromatography to separate water-in-oil (W/O) emulsion.

P-stereogenic PNP pincer-Pd catalyzed intramolecular hydroamination of amino-1,3-dienes.

A new P-stereogenic PNP pincer-Pd complex was readily prepared from optically pure 2,6-bis[(boranato(tert-butyl)methylphosphino)methyl]pyridine. It was used in the asymmetric intramolecular hydroamination of amino-1,3-dienes, with the desired products being obtained in good yields and with excellent regioselectivities and up to moderate enantioselectivities. The absolute configuration of one of the hydroamination products was determined by X-ray crystallography studies. This simple and efficient procedure can be used for the synthesis of allyl-type chiral pyrrolidine derivatives.

Anti-tumor activities of Au(I) complexed with bisphosphines in HL-60 cells.

We found that Au(I) complexed with 2,3-bis(tert-butyl(methyl)phosphino) quinoxaline (10) was a potent anti-tumor agent (half-maximal growth inhibitory concentration, GI50=0.87µM) with broad anti-tumor activity. In particular, the activity of complex 10 was high in tumor cell lines derived from the colon and ovary. Treatment with complex 10 resulted in the apoptosis of HL-60 cells. The ligand for the preparation of complex 10 is commercially available implying that complex 10 might be a good drug candidate for cancer therapy.

P-Stereogenic PCP pincer-Pd complexes: synthesis and application in asymmetric addition of diarylphosphines to nitroalkenes.

Novel P-stereogenic PCP pincer-Pd complexes were designed and prepared in short steps from optically pure tert-butylmethylphosphine-borane. These optically active Pd-complexes were successfully applied in asymmetric addition of diarylphosphines to nitroalkenes with high yields and good enantioselectivity.

Chemoselective transfer hydrogenation of α,ß-unsaturated ketones catalyzed by pincer-Pd complexes using alcohol as a hydrogen source.

A pincer-Pd complex was utilized in the chemoselective transfer hydrogenation of α,ß-unsaturated ketones using n-BuOH as a hydrogen source and solvent. Good to excellent yields were obtained for various substrates even with reducible groups. Based on deuterium-labeling experiments, the reaction mechanism is proposed to occur via a pincer-Pd-hydride intermediate.

Three-hindered quadrant phosphine ligands with an aromatic ring backbone for the rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes.

The three-hindered quadrant phosphine ligands (R)-1-tert-butylmethylphosphino-2-(di-tert-butylphosphino)benzene ((R)-3H-BenzP*) and (R)-2-tert-butylmethylphosphino-3-(di-tert-butylphosphino)quinoxaline ((R)-3H-QuinoxP*) exhibited good to excellent enantioselectivities in the rhodium-catalyzed asymmetric hydrogenation of selected dehydroamino acid derivatives, enamides, and ethenephosphonates.

Rigid P-chiral phosphine ligands with tert-butylmethylphosphino groups for rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes.

Both enantiomers of 2,3-bis(tert-butylmethylphosphino)quinoxaline (QuinoxP*), 1,2-bis(tert-butylmethylphosphino)benzene (BenzP*), and 1,2-bis(tert-butylmethylphosphino)-4,5-(methylenedioxy)benzene (DioxyBenzP*) were prepared in short steps from enantiopure (S)- and (R)-tert-butylmethylphosphine-boranes as the key intermediates. All of these ligands were crystalline solids and were not readily oxidized on exposure to air. Their rhodium complexes exhibited excellent enantioselectivities and high catalytic activities in the asymmetric hydrogenation of functionalized alkenes, such as dehydroamino acid derivatives and enamides. The practical utility of these catalysts was demonstrated by the efficient preparation of several chiral pharmaceutical ingredients having an amino acid or a secondary amine component. A rhodium complex of the structurally simple ligand BenzP* was used for the mechanistic study of asymmetric hydrogenation. Low-temperature NMR studies together with DFT calculations using methyl α-acetamidocinnamate as the standard model substrate revealed new aspects of the reaction pathways and the enantioselection mechanism.

Enantiopure 1,2-bis(tert-butylmethylphosphino)benzene as a highly efficient ligand in rhodium-catalyzed asymmetric hydrogenation.

An electron-rich P-stereogenic bisphosphine ligand named "BenzP*" was conveniently prepared from o-dibromobenzene and enantiopure tert-butylmethylphosphine-borane. Its rhodium complex exhibited excellent enantioselectivities of up to 99.9% and high catalytic activity of up to 10,000 h(-1) TOF in asymmetric hydrogenations of various functionalized alkenes.

Thermal and transport properties of ionic liquids based on benzyl-substituted phosphonium cations.

The physicochemical properties of two novel ionic liquids based on benzyltriethylphosphonium and benzyltributylphosphonium cations are described in this report. It was found that both benzyl-substituted phosphonium cations gave low-melting salts in combination with a bis(trifluoromethylsulfonyl)amide anion. The thermogravimetric analysis suggested that the benzyl-substituted phosphonium ionic liquids showed higher thermal stability than those of not only the alkyl-substituted phosphonium ILs but also the corresponding benzyl-substituted ammonium compounds. The benzyl-substituted phosphonium ionic liquids also exhibited relatively high conductivities when compared to those of the corresponding ammonium compounds. These results indicate an improving effect of introducing a benzyl group into the phosphonium cations on both the thermal stability and the conductivity.