Thermodynamics of metal-ligand bond formation. XII. Adducts of Monothio-β-diketone complexes with pyridine and bipyridine

Abstract

Thermodynamic data are reported for the addition of pyridine and bipyridine in benzene solution to monothio-β-diketone complexes, ML₂, of nickel(11), copper(11), zinc(11) and mercury(11). NiL₂ gives NiL₂(py)₂ and NiL(bpy); ZnL₂ gives ZnL₂(py) and ZnL₂(bpy); in both cases the data show that bipyridine is bidentate. CuL₂ gives CuL₂ (py) and CuL₂ (bpy), with almost equal enthalpies of formation, but the higher stability of CuL₂(bpy) shows bipyridine is probably bidentate. HgL₂ gives HgL₂(py) and a reaction with bipyridine which shows that an extremely unstable adduct is formed. All data were obtained by calorimetric titration.