the complexation reaction between 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (kryptofix5) ligand with zn2+, ni2+, co2+, pb2+, mn2+ and cu2+ ions were studied conductometrically in different acetonitrile-nitromethane (an-nm) and acetonitrile-methanol (an-meoh) mixtures. the formation constants of the resulting 1:1 complexes were calculated from the computer fitting of the molar conductan...

The palladium-catalyzed intramolecular coupling of allyl stannanes with allyl carboxylates provides a general synthesis of five- and six-membered-ring carbocycles. The intramolecular coupling leads selectively to trans five-membered carbocycles and cis six-membered carbocycles, regardless of the cis or trans configuration of the allylic functions in the starting material. For example, the stere...

Available surface complexation models for birnessite required the inclusion of bidentate bonds or the adsorption of cation-hydroxy complexes to account for experimentally observed H/M exchange. These models contain inconsistencies and therefore the surface complexation on birnessite was re-examined. Structural data on birnessite indicate that sorption sites are located on three oxygens around a...

The Ca2+ concentration and hydrolysis degree [-COO-] dependence of the self-complexation of partially hydrolyzed poly(acrylamide) (HPAM) chains in CaCl2 aqueous solution was systematically investigated by a combination of static and dynamic laser light scattering. We have, for the first time, revealed a transition between the intrachain and interchain complexations. For each given HPAM sample, ...

A bromonaphthalene-labeled poly(acry1ic acid), BNPAA, was synthesized and found to be phosphorescent in solution at room temperature. The phosphorescence of the polymer was employed to investigate (1) the influence of pH on the conformations of the polymer in aqueous solutions, (2) the interactions of BNPAA with complementary polymers [poly( 1-vinyl-2-pyrrolidinone) and poly(ethy1ene oxide)], a...

The probiotic industry faces the challenge of retention of probiotic culture viability as numbers of these cells within their products inevitably decrease over time. In order to retain probiotic viability levels above the therapeutic minimum over the duration of the product's shelf life, various methods have been employed, among which encapsulation has received much interest. In line with explo...