The acid-base properties of 2,2′-biimidazolyl (2,2′-BiIm) are studied using methods of pH-potentiometry and spectrophotometry. In aqueous solutions, 2,2′-BiIm shows a tendency to self-associate. The characteristics of complex formation of Cu(II) with 2,2′-biimidazolyl are determined in a wide range of pH and reagent concentrations using potentiometric titration. EPR, and NMR. In solutions of pH ranging from 2 to 5, the specific feature of complexation between copper(II) and 2,2′-BiIm is a formation, in an excess of the ligand, of stable binuclear complexes, in which the 2,2′-BiIm molecules act as bridging Iigands
