Influence of the nature of organic ligands on the character of thermal decomposition products of CoII and NiII pivalate complexes with amino derivatives of pyridine

The thermal stability and the solid-state thermal decomposition of the known mononuclear cobalt(II) and nickel(II) complexes [H2N(C5H3N)N(H)C(Me)=NH]M(OOCBut)2, [(NH2)2C6H2Me2]3M(OOCBut)2 and the new compounds L2M(OOCBut)2 (L = = (2-NH2)C5H3N, (2-NH2)(6-Me)C5H3N), and [(2,6-NH2)2C5H3N]2Ni(OOCBut)2 were studied by differential scanning calorimetry and thermogravimetric analysis. Efficient methods were developed for the synthesis of these complexes. The mononuclear complexes are thermally quite stable. The thermal stability of the complexes depends on the nature of the ligand and decreases in the series (2,6-NH2)2C5H3N > H2N(C5H3N)NHC(Me)=NH > (NH2)2C6H2Me2 > (2-NH2)C5H3N > (2-NH2)(6-Me)C5H3N. The nickel(II) complexes are thermally more stable than the related cobalt(II) complexes. The thermolysis (<500 °C) of Co and Ni pivalates is a destructive process. The phase composition of the decomposition products is determined by the nature of metal and coordinated ligands.