in this study the binding abilities of 1,3-calix[4]biscrown-6 (l) toward ba2+ and ca2+ have beenestablished in methanol by spectrophotometric measurements at 25±0.1 °c and 0.01 m ionicstrength, and with using specfit computer program; stability constants for 2 : 1, metal : ligandcomplexes has been estimated

a proton nmr method for the drtermination of salvation numbers of alkaline earth cations with hexamethyl phosphoramide (hmpa) in nitromethane (nm) as diluents is described. the method is based on monitoring the resonance frequency of hmpa protons as a function of hmpa / metal ion molar ratio at constant metalion concentration. the average salvation number of cations,  , at any hmpa / metal ion ...

A proton NMR method for the drtermination of salvation numbers of alkaline earth cations with hexamethyl phosphoramide (HMPA) in nitromethane (NM) as diluents is described. The method is based on monitoring the resonance frequency of HMPA protons as a function of HMPA / metal ion molar ratio at constant metalion concentration. The average salvation number of cations,  , at any HMPA / metal ...

alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1h)-ones in high yields at 80 °c. our results showed that biginelli reaction not only is ph dependent, but the cation of catalyst plays an important role.

Alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1H)-ones in high yields at 80 °C. Our results showed that Biginelli reaction not only is pH dependent, but the cation of catalyst plays an importan...