Enhanced Efficiency of Anionic Guerbet-Type Amino Acid Surfactants.

This study investigates the surfactant properties and efficiency of linear and Guerbet-type amino acid surfactants. Utilizing a Wilhelmy plate method, we assessed the colloidal efficiency of these surfactants, with the lowest observed critical micelle concentration at 0.046 mmol L, significantly reducing surface tension to as low as 25.

α-Pyridinyl Alcohols, α,α'-Pyridine Diols, α-Bipyridinyl Alcohols, and α,α'-Bipyridine Diols as Structure Motifs Towards Important Organic Molecules and Transition Metal Complexes.

Background: The preparation and use of pyridinyl alcohols as ligands showed incredible increment in the past three decades. Important property of pyridinyl alcoholato ligands is their strong basicity, which is mainly due to the lack of resonance stabilization of the corresponding anion. This strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion.

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands.

Four new Grubbs-type precatalysts [RuCl(HIMes)(O^N)(=CHPh)], where [O^N = α,α-diphenyl-(3-methylpyridin-2-yl)methanolato, α,α-diphenyl-(4-methylpyridin-2-yl)methanolato, α,α-diphenyl-(5-methylpyridin-2-yl)methanolato and α,α-diphenyl-(3-methoxypyridin-2-yl)methanolato] were synthesized and tested for their activity, stability and selectivity in the 1-octene metathesis reaction. Overall the precatalysts showed good activity and high stability for the metathesis of 1-octene at temperatures above 80 °C and up to 110 °C. Selectivities towards the primary metathesis products, i.

A comparison of low and high activity precatalysts: do the calculated energy barriers during the self-metathesis reaction of 1-octene correlate with the precatalyst metathesis activity?

The self-metathesis reaction of 1-octene with several well-known Grubbs-type precatalysts and the new Z-selective Grubbs precatalyst were studied with molecular modeling. The obtained Gibbs-free energy values for all the steps during the productive metathesis of 1-octene were compared to the values obtained for some low catalytic activity precatalysts. Determining how the Gibbs-free energy values of highly active precatalysts compare to that of low catalytic activity precatalysts gave a deeper insight into the mechanism.

A molecular modeling study of the changes of some steric properties of the precatalysts during the olefin metathesis reaction.

The productive self-metathesis of 1-octene with a series of new phosphine ligated Grubbs-type precatalysts was studied. The resulting structures were used to compare some steric properties of the new precatalysts with those of well-known precatalysts. The possibility of α-CC agnostic stabilization as well as the ability of the ligands to shield the metal was studied.

Improved metathesis lifetime: chelating pyridinyl-alcoholato ligands in the second generation Grubbs precatalyst.

Hemilabile ligands can release a free coordination site "on demand" of an incoming nucleophilic substrate while occupying it otherwise. This is believed to increase the thermal stability and activity of catalytic systems and therefore prevent decomposition via free coordination sites. In this investigation chelating pyridinyl-alcoholato ligands were identified as possible hemilabile ligands for incorporation into the second generation Grubbs precatalyst.

DFT investigation of the 1-octene metathesis reaction mechanism with the Phobcat precatalyst.

The productive self-metathesis reaction of 1-octene in the presence of the Phobcat precatalyst [RuCl(2)(Phoban-Cy)(2)(=CHPh)] using density functional theory was investigated and compared to the Grubbs 1 precatalyst [RuCl(2)(PCy(3))(2)(=CHPh)]. At the GGA-PW91/DNP level, the geometry optimization of all the participating species and the PES scans of the various activation and catalytic cycles in the dissociative mechanism were performed. The formation of the catalytically active heptylidene species is kinetically and thermodynamically favored, while the formation of trans-tetradecene is thermodynamically favored.

Development of microporous drug-releasing films cast from artificial nanosized latexes of poly(styrene-co-methyl methacrylate) or poly(styrene-co-ethyl methacrylate).

Two sets of copolymers comprising of styrene and either methyl or ethyl methacrylate as comonomer were conveniently synthesized by microemulsion copolymerization. The purified materials were characterized by GPC-MALLS and were shown to form artificial nanolatexes in THF. ATR-FTIR analysis revealed differences in copolymer composition and based on the copolymer properties, a selection of copolymers was chosen to cast drug-loaded, microporous films that exhibit microencapsulation of drug agglomerates.