The formation constants and Gibbs free energy for the interaction of RnSnClm (n = m = 2, R = Me, Ph, n-Bu or n = 4, m = 0, R = Ph) compounds as acceptors, with ML complexes (H2L = N,N'-bis(salicylidene)-2-aminobenzylamine (salabza-H2) and its derivatives, M = Mn2+ or Zn2+), as donors in N,N'-dimethylformamide (DMF) as solvent were studied. These parameters were measured by using UV-vis spectrop...

The misfolding of the prion protein (PrP) to aggregated forms is linked to several neurodegenerative diseases. Misfolded oligomeric forms of PrP are associated with neurotoxicity and/or infectivity, but the molecular mechanism by which they form is still poorly understood. A reduction in pH is known to be a key factor that triggers misfolded oligomer formation by PrP, but the residues whose pro...

The protonation constant of hexamethylenetetramine (urotropine) was determined by a potentiometric and a spectrophotometric method. The calculations gave log K(HL) (concentration constants): 4.89 at mu = 0.1 and 5.05 at mu = 0.5. The temperature was 25 degrees and potassium chloride was used to adjust the ionic strength.

Reactivation of diethyl p-nitrophenyl phosphate inhibited human serum cholinesterase by pyridine-Z-aldoxime methiodide and isonitrosoacetophenone has been investigated as a function of reactivator concentration, pH, and temperature in boric acid-borax buffer and in salt solution. Constants shown were the dissociation constants of the diethylphosphoryl cholinesterase reactivator complex for the ...

The acid-base chemistry of a tetraprotic, ampholyte ACE inhibitor, lisinopril, was studied by different methods. Potentiometry in aqueous medium and a co-solvent technique in methanol-water mixtures as well as 1 H NMR-pH titration were applied for the highly precise measurement of protonation macroconstants. The log K values of lisinopril (at 25.0°C and 0.15 M ionic strength) were found: log K1...

The acid dissociation constants of long-chain esters of carnitine (5-hydroxy-~,trimethylammonium-butyrate) above the critical micelle concentration were determined potentiometrieally at several concentrations of added KC1. As the degree of protonation 5 increases the apparent pK values decrease owing to the increased positive charge on the micelle. The difference in pK between the neutral (zwit...

The stability of coordination compounds metal ions with ligands is fundamental importance for elaborating upon practical sensors the detection and quantification in environmental samples. In this work, constants silver(I) complexes 2-mercaptoimidazole (2MI) a mixed water–dimethyl sulfoxide (DMSO) solvent were determined at 298.15 K 308.15 K. It was found that increasing temperature, decreases. ...