equilibria of the reaction of molybdenum(vi) with l-aspartic acid (asp) and l- glutamic acid(glu) have been studied by spectrophotometric measurements in mixed solvent systems at an ionicstrength of 0.2 mol/dm3 sodium perchlorate, employed (15, 20, 25, 30± 0.1°c) at ph ranges of 3.2to 5.5 with a high ratio of ligand to metal. the stability constants of the complexes and theresulting free energy...

The protonation constants of glycine, L-alanine, glycyl-glycine, glycyl-glycyl-glycine and glycyl-L-alanine have been determined in 10-80% (v/v) ethanol-water mixtures at 25 °C and constant ionic strength (0.1 mol L-1 sodium perchlorate), by potentiometric technique and calculated using a suitable computer program, which employs a nonlinear least-squares method. The effect of solvent compositio...

where the values of the forward (kd) and reverse (kp) rate constants may be different from those in the ground state because of differences in the properties of the 2-naphthol in these two states (for example, Ka 6= K ∗ a in part I). The objective of this experiment is to determine the deprotonation/protonation rate constants of 2-naphthol in its lowest excited singlet state in aqueous solution...

The stability constants and enthalpies of formation of silver (I) complexes with histidine and imidazole were determined. Two types of complexes were found: AgL and AgL+2 . The second is much more stable that is evidenced by the higher stability constants and enthalpies of formation. For the two systems, the respective constants and enthalpies are very close one to another that suggests similar...

A systematic study has been performed of the proton affinity of a large family of agonists and antagonists of the α1-adrenoceptor at the B3LYP/6-31G* level of theory. After a conformational search, all the N atoms were considered as protonation sites and protonation energy values were determined. The inclusion of solvation by means of the Onsager model yielded stabilization in the proton affini...

The formation constants of the species formed in the systems H+ + cytidine 5-monophosphate (CMP)and H+ + cytidine 5-monophosphate + Tl (I) ion have been determined in aqueous solution in a widepH range of 1.5 to 10.5 at 25 °C and different ionic strengths ranging from 0.1 to 1.5 moldm-3NaClO4, NaNO3, and NaCl using potentiometric-spectrophotometric technique. The composition ofthe complexes was...

Mixed dissociation constants of four drug acids, i.e. silychristin, silybinin, silydianin and mycophenolate at various ionic strengths I of range 0.01 and 0.30 and at temperatures of 25 and 37 ◦C were determined using the SQUAD(84) regression analysis program applied to pH-spectrophotometric titration data. The proposed strategy of an efficient experimentation in a protonation constants determi...