The complexation reactions between Cu2+, Pd2+ and Ni2+ metal ions with promethazine (PM) in water or DMF were studied by the spectrophotometric methods at [(15, 25,35 and 45±0.1) °C]. The complexation process was optimized in terms of pH, temperature and contact time. The stoichiometry of the complex was found to be 1:1 (metal ion/ligand). The formation constants of the resulting complexes were...

the formation constants of the species formed in the systems fr + glycine + dioxovanadium(v) + and h+ + glycine have been determined in aqueous solutions of methanol at 25 °c and constant ionicstrength, using spectrophotometric and potentiometric techniques. it was shown thatdioxovanadium(v) forms two mononuclear 1 : land 1:2 complexes with glycine. the formationconstants in various media were ...

The prototropic exchange equilibria of two drugs, nizatidine (I) and ranitidine(II), and also of structurally related the N,N'-dimethyl-2-nitro-1,1-ethenediamine molecule (III) were investigated. From the changes in electronic spectra in media of various acidity several protonation constants were determined. For pK values were -0.82, 1.95, and 6.67; for ranitidine pK values were 1.95 and 8.13; ...

Effects of pH, temperature, and syrup concentration on color formation in glucose syrups were studied and the shelf life of syrups under various conditions was estimated. Temperatures of 5, 25, and 45 ºC, pH values of 4, 5, and 6 as well as concentrations of 30, 40, 50, 60, 70, and 80 ºBrix were examined. After 26 weeks no significant color changes were observed at 5 ºC. At 45 ºC, color formati...

The purpose of this work was to synthesize and characterize the thiatetraaza macrocycle 1-thia-4,7,10,13-tetraazacyclopentadecane ([15]aneN4S). Its acid-base behaviour was studied by potentiometry at 25 °C and ionic strength 0.10 M in KNO3. The protonation sequence of this ligand was investigated by 1H-NMR titration that also allowed the determination of protonation constants in D2O. Binding st...

Abstract The preparation 0f azo dyes is the subject of this research. 4-hydroxycoumarin with each ofo-amino benzoic acid (3-[o-Amino acidazo]-4-hydroxycoumarin]) (B 1 ) and Sulfa guanidine (3-[Sulfa azo]-4-hydroxycoumarin) 2 were syntheses. Azo compounds characterized by I.R, CHN, H-NMR Elctronic Mass spectroscopy. At various pH levels, electronic spectra these investigated in terms acid-base p...

Interaction of glyphosate (N-(phosphonomethyl)-glycine) with six polyamines (ethylendiamine, cadaverine, putrescine, triethylenetetramine, spermine, and tetraethylenepentamine) was studied potentiometrically. Several species of different stoichiometry are formed in the various systems, according to the general formation reaction i1 (j 2 3) (i 1 j 2 3) AH 1 H (glp) 5 A(glp)H i j i 1 j (where A 5...