METAL COMPLEXES OF D-GLUCOSAMINE AND ITS DERIVATIVES. IV. DETERMINATIONS OF STABILITY AND EQUILIBRIUM CONSTANTS OF METAL COMPLEXES OF D-GLUCOSAMINE BY PH TITRATION METHOD.

Abstract

Stability constants and equilibrium constants of seven metal complexes of D-glucosamine (I) with Cu, Pb, Zn, Co, Cd, Ni, and Mn were determined by pH titration methdo. The possibility of complex formation of I with metal ions were examined and Bjerrum's method for calculations of stability constants was also studied, and was found to be applicable to these metal complexes. Complexes having a 1 : 1 and 2 : 1 of I to a metal ion were formed in the solution and their stability constants were calculated. Copper complexes were found to be the most stable compound and had the largest log K1 and log K2 values among these metal complexes. From the results of hydrolysis constants calculated of these complexes, the copper complex was found to be most susceptible to hydrolysis. Further study showed that the dimerization of complex occurred only in the case of the copper complex. Consequently, the formation path way and the possible structures for these metal complexes were proposed based upon the experimental data.