Chelates of praseodymium-, neodymium-, samarium-, gadolinium-, holmium-, erbium-, thulium- and ytterbium(III) and some symmetric 1,5-diphenyl-3-cyanoformazans

Potentiometric, conductimetric, ir, TG, molar conductance and magnetic susceptibility studies have been carried out on the complexes of trivalent Pr, Nd, Sm, Gd, Ho, Er, Tm and Yb with some symmetric 1,5-diphenyl-3-cyanoformazans. The ionisation constants of the ligands and the formation constants of their metal chelates have been determined potentiometrically in solution. Complexation has also been studied by a conductimetric titration method.