THERMAL LATENT COORDINATION-COMPOUNDS - THE THERMAL-DEGRADATION OF IMIDAZOLE AND PYRAZOLE ADDUCTS OF METAL ACETATES

The thermal behaviour of complexes of the type M(HIm)2ac2 (HIm = imida zole, ac = acelate, M = Co, Ni, Cu) is different. Comparable to the th ermal degradation of Ni(acac)2(HIm)2 [10] the Ni(HIm)2ac2 loss acetic acid by formation of Ni(Im)2. All nitrogen ligands are splitt off from the copper complex by formation of stable basic copper acetate. The c obalt compound eliminated acetic acid partially while acetate and imid azolate bridging species are obtained. The thermal behaviour of the ac etate complexes of pyrazole and the bulky 3,5-dimethylpyrazole is quit e similar. In a first step pyrazoliumacetate is removed. The crystal s tructure of Ni(HPz)4ac2 is determined by X-ray diffraction: monocline, space group C 2/c. The water molecule represents the centre of two N- H...O-H...O-bridges. The system of H-bridges in the compound relieves the proton transfer, indicated by the elimination of pyrazolium acetat e.