Search results for "Styrene"

Rbt1 Protein Domains Analysis in Candida albicans Brings Insights into Hyphal Surface Modifications and Rbt1 Potential Role during Adhesion and Biofi…

2013

Cell wall proteins are central to the virulence of Candida albicans. Hwp1, Hwp2 and Rbt1 form a family of hypha-associated cell surface proteins. Hwp1 and Hwp2 have been involved in adhesion and other virulence traits but Rbt1 is still poorly characterized. To assess the role of Rbt1 in the interaction of C. albicans with biotic and abiotic surfaces independently of its morphological state, heterologous expression and promoter swap strategies were applied. The N-terminal domain with features typical of the Flo11 superfamily was found to be essential for adhesiveness to polystyrene through an increase in cell surface hydrophobicity. A 42 amino acid-long domain localized in the central part o…

Hydrophobically Directed Aldol Reactions: Polystyrene-SupportedL-Proline as a Recyclable Catalyst for Direct Asymmetric Aldol Reactions in the Presen…

2007

The cover picture shows the aldol reaction between ketones and arylaldehydes carried out by using a polystyrene-supported L-proline catalyst. This material furnishes aldol products in high yields and stereoselectivities. Screening of solvents showed that these reactions take place only in the presence of water. This solvent effect, coupled with the high stereoselectivities observed, has been explained by the formation of a hydrophobic core in the inner surface of the resin with the hydrophilic proline moiety in the resin/water interface. Such a microenvironment promotes the aldol reaction and increases the stereoselectivity. Recycling investigations have shown that this material can be reus…

Styrene polymerization using nickel(II) complexes as catalysts

2005

International audience; Styrene polymerization is investigated with neutral and cationic Ni(II) complexes, i.e. Ni(bipy)Me-2, 1, Ni(bipy)Br-2, 2, Ni(phen)Br-2, 3, or Ni(Me(2)phen)Br-2, 4, Ni(acac)(2), 5, (bipy = 2,2 '-bipyridine, phen = phenanthroline, Me,phen = 2,9-dimethyl-1, 10-phenanthroline, acac acetylacetonate), activated by [NHMe2Ph][B(C6F5)(4)] or B(C6F5)(3) as cocatalysts, in the presence of AlMe3. The influence on the polystyrene features and the reaction kinetics of the nickel complex and boron activator, the Al/Ni or B/Ni molar ratios as well as the monomer concentration are studied. Catalytic systems derived from 2, 3 or 5 and [NHMe2Ph][B(C6F5)(4)] at a Ni:B:Al ratio of 1: 1:5…

1981

Refractive indices and refractive index increments of the system polystyrene/trans-decalin were measured under pressures up to 500 bar and at temperatures between 20 and 60°C. The measurements were performed with a new, recently designed interferometer. The results demonstrate a sufficient agreement of the refractive index values measured at different temperatures and pressures with the equations of Eykman and Gladstone-Dale whereas the Lorenz-Lorentz equation indicates larger deviations. The experimental data of the refractive index increment follow none of the refractive index mixture rules. It is therefore recommended to determine refractive index increments at different pressures experi…

Density Functional Theory Investigation on the Nucleation and Growth of Small Palladium Clusters on a Hyper-Cross-Linked Polystyrene Matrix

2014

Density functional theory calculations were employed to investigate the nucleation and growth of small palladium clusters, up to Pd9, into a microcavity of the porous hyper-cross-linked polystyrene (HPS). The geometries and the electronic structures of the palladium clusters inside the HPS cavity, following the one-by-one atom addition, are affected by a counterbalance between the Pd–phenyl (Pd−Φ) and Pd–Pd interactions. The analysis performed on energetics, cavity distortions, and cluster geometries indeed suggest that the cluster growth is dominated by the Pd−Φ interactions up to the formation of Pd4 aggregates, whereas the metal–metal interactions actually rule the growth of the larger c…

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction

2019

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.

A pillar[5]arene-containing cross-linked polymer: synthesis, characterization and adsorption of dihaloalkanes and n-alkylene dinitriles

2016

A pillar[5]arene-containing cross-linked polymer was synthesized via Williamson reaction involving monohydroxy pillar[5]arene with chloromethylated polystyrene. Its adsorption behavior towards guests was investigated. It was found that the pillar[5]arene-containing polymer exhibited good adsorption capacities towards dihaloalkanes and dinitriles by host-guest complexation.

Rh(I) Coordination Chemistry of Chiral α-Aminophosphine(η6-arene)chromium Tricarbonyl Ligands

2003

The diastereoselective addition of Ph(2)PH to the chiral ortho-substituted eta(6)-benzaldimine complexes (eta(6)-o-X-C(6)H(4)CH=NAr)Cr(CO)(3) (1, X = MeO, Ar = p-C(6)H(4)OMe; 2, X = Cl, Ar = Ph) leads to the formation of the corresponding chiral aminophosphines (alpha-P,N) Ph(2)P-CH(Ar(1))-NHAr(2) (3, Ar(1) = o-C(6)H(4)(OCH(3))[Cr(CO)(3)], Ar(2) = p-C(6)H(4)OCH(3); 4, Ar(1) = o-C(6)H(4)Cl[Cr(CO)(3)], Ar(2) = Ph) in equilibrium with the starting materials. The uncomplexed benzaldimine (o-ClC(6)H(4)CH=NPh), 2', analogously produces an equilibrium amount of the corresponding aminophosphine Ph(2)P-CH(Ar(1))-NHAr(2) (4', Ar(1) = o-C(6)H(4)Cl, Ar(2) = Ph). Depending on the equilibrium constant, t…

Tapered copolymers of styrene and 4‐vinylbenzocyclobutene via carbanionic polymerization for crosslinkable polymer films

2019

Films from styrene–butyl acrylate lattices using maleic or succinic surfactants: mechanical properties, water rebound and grafting of the surfactants

2000

Abstract A series of anionic and zwitterionic maleic surfactants have been synthesized and engaged in styrene–butyl acrylate emulsion polymerization. Some non-reactive succinic analogs have been synthesized in order to perform their comparison with the maleic surfactants in polymerization experiments. Films from the obtained lattices were cast, and their mechanical properties and the water rebound were tested. The results of water rebound demonstrate significant difference between the films prepared with maleic or succinic surfactants. Water rebound of the films after 34 days in the case of succinic surfactants was found to be between 51 and 95%, while for maleic surfactants it is only 25–4…