Stability of Metal(II)-1, 1, 1-Trifluoro-4-mercapto-4-(2-thienyl)-3- butene-2-one-Nitrogeneous Base Ternary Complex on the Basis of HSAB Principle

Abstract

Synergistic extraction constants for metal(II)-STTA(1, 1, 1-trifluoro-4-mercapto-4-(2-thienyl)-3-butene-2-one=HR)-nitrogeneous base(2, 2′-bipyridine=bpy, 1, 10-phenanthroline=phen) system were expressed by the HSAB parameters proposed previously. Stabilities of the synergistic adducts, ZnR₂(bpy), ZnR₂(phen), CdR₂(bpy) and CdR₂(phen), were also discussed by assuming the additive property of these parameters. The estimated stabilities were examined by ¹HNMR and IR measurements. The metal(II)-STTA bond was weakened by the coordination of additives. The formation of a ternary complex was considered to proceed through the reaction between a cationic complex and a chelate anion in the synergistic extraction system when a neutral bidentate nitrogeneous base such as phen or bpy was used.