The copper-catalyzed [3+2] azide-alkyne cycloaddition and the Staudinger ligation are readily applicable and highly efficient for the immobilization of cobalt Schiff base complexes onto polystyrene resins. Stepwise synthesis of polymer-bound Schiff bases followed by their subsequent complexation with metal ions were successfully carried out. Direct covalent attachment of preformed homogeneous c...

Many empirical parameters have been suggested to measure solvent effects in chemical reactions. Gutmann's donor number has been a successful parameter to quantify the electron-donating property of the solvent molecule; it is defined as the enthalpy change of the addition reaction of solvent molecule to SbCl(5) in 1,2-dichloroethane. Calorimetric measurements can be applied to determine the qu...

A cloud point extraction process using the nonionic surfactant Triton X-114 for extracting mercury from aqueous solutions was investigated. The method is based on the complexation reaction of Hg(II) with Thio-Michler's Ketone (TMK) and micelle-mediated extraction of the complex. The optimal extraction and reaction conditions (e.g., pH, reagent concentration, effect of time) were studied, and th...

Two new heterogenized epoxidation nanocatalysts based on molybdenum and tungsten compounds were prepared withcovalent grafting of MCM-41 with 3-aminoropropyl trimethoxysilane and subsequent reaction with diphenylphosphinobenzaldehyde and complexation with M (Mo, W)O2(acac)2. X-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properti...

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 mechanism of the SmI2 -mediated reduction of unactivated esters has been studied using a combination of kinetic, radical clocks and reactivity experiments. The kinetic data indicate that all reaction components (SmI2 , amine, H2 O) are involved in the rate equation and that electron transfer is facilitated by Brønsted base assisted deprotonation of water in the transition state. The use of ...

Controlling radical intermediates and thus catalysing and directing complex radical reactions is a central feature of S-adensosylmethionine (SAM)-dependent radical enzymes. We report ab initio and DFT calculations highlighting the specific influence of ion complexation, including Mg2+ , identified as a key catalytic component on radical stability and reaction control in 7-carboxy-7-deazaguanine...

The synthesis of new vicinal diamines based on aziridine and azetidine cores as well as the comparison of their catalytic activities as ligand in the Suzuki-Miyaura coupling reaction are described in this communication. The synthesis of threeand four-membered ring heterocycles substituted by a methylamine pendant arm is detailed from the parent nitrile derivatives. Complexation to palladium und...

a new schiff base ligand, 2,2'-{pyridine-2,6-diylbis[nitrilo(e)methylylidene]}bis(4 bromophenol),has been synthesized by reaction of the 2,6-diamino pyridine with 5-bromo salicylaldehyde at ethanolunder refluxing. the structure of the synthesized compound resulted from the ir, 1hnmr, ms anduv spectroscopy and elemental analysis data. formation constant (kf) value of it’s complexes withcu2+, ni2...

The 1,4-bis(3-guaiazulenylmethylium)benzene and 1,4-bis[1-(4,6,8-trimethylazulenylmethylium)]benzene dication salts were synthesized via an acid-catalyzed condensation/dehydration protocol with guaiazulene-terephthalaldehyde (2 : 1 ratio), and 4,6,8-trimethylazulene-terephthalaldehyde (2 : 1 ratio) respectively in one-pot processes. A similar condensation reaction with the parent azulene led to...