POTENTIOMETRIC STUDIES ON COMPLEXES OF SILVER(I) IN SOLUTIONS .7. THESTABILITY OF AG(I) COMPLEXES WITH 2-SUBSTITUTED IMIDAZOLES IN AQUEOUS-SOLUTION

Stability constants of AS(I) complexes with 1-R-2-methylimidazoles (R = C2H5, C3H7, C4H9), 1-R-2-hydroxymethylimidazoles (R = CH3, C2H5, C3H 7, C4H9) and 1-alkyl-2-imidazolecarboxaldehydes (R = CH3, C3H7) have b een determined potentiometrically by simultaneous measurements of [Ag] and [H3O+]. All measurements were run at 25 +/- 0.1 degrees C at a i onic strength I = 0.5 (KNO3). The contribution of IIM-L bonding to the co-ordination bonds is discussed. The II-electron-acceptor properties of studied imidazoles decrease in the order:1-R-2-CHOIm > 1-R-2-CH(2) OHIm > imidazole > 1-R-2MeIm and in the group of unsubstituted heteroc yclic bases the II-acceptor strength decreases in the following order: pyrazine > pyrimidine > 1,2,4-triazole > pyrazole > thiazole congruen t to pyridazine > > pyridine > imidazole.