Preparation, spectral and thermal properties of Mg(II) and Cu(II) complexes with N,N-diethylnicotinamide

The thermal decomposition of the complexes Mg(ac)(2) . (Et(2)na)(2) . 2H(2) O (I), Mg(Cl(3)ac)2 . (Et(2)na)(2) . 3H(2)O (II), and Cu(Cl(3)ac)(2) . (Et( 2)na)(2) . 3H(2)O (III) (where ac = CH3COO-, Cl(3)ac = Cl-3 CHCOO-, and Et( 2)na = N,N-diethylnicotinamide) had been investigated in air in the tempera ture range 20-1000 degrees C by means of thermogravimetry (TG) and differen tial thermal analysis (DTA). The composition of the complexes and the solid state intermediate and resultant products of thermolysis had been identifi ed by means of elemental analysis and complexometric titration. The possibl e scheme of destruction of the complexes is suggested. Heating the compound s first results in a release of water molecules. The loss of the volatile l igand (Et(2)na) occurs in one step. The thermal stability of the complexes increases in the sequence: II, III, I. The final products of the thermal de composition were MgO (land II) and CuO (III). The IR, EPR, and electronic s pectral analyses were used. Et(2)na is coordinated to Mg(II) and Cu(II) thr ough the nitrogen atom of its heterocyclic ring. EPR data suggest a dimeric structure of compound III.