Study of Synthesis, Characterization, DFT, and In Vitro Biological Activity of Cu(II), Co(II), and Fe(II) Metal Complexes Based on Heterocyclic Azo Pyrazole Dye Ligand

Table 3

Thermogravimetric analysis (TGA/DTA) data of the Cu(II), Co(II), and Fe(II) complexes.

Compound	Step	Temp. range ˚C	DTAMax°C	Total weight loss estimated (calcd.), %	Decomposition assignment	Residual
Cu(II)L	1^st	64–168	80.4	12.1 (12.0)	Loss of 3½ H2O (lattice)	CuO
	2^nd	173–624	520	87.0 (87.8)	Loss of 2Cl + 1H2O (coord.water) + C21H17N5O2 ligand
Co(II)L	1^st	40–669	400	92.6 (92.1)	Loss of 1H2O (lattice) + 1H2O (coord.water) + 2Cl + C21H17N5O2 ligand	¼ Co2O2
Fe(II)L	1^st	51–193	99.9	10.3 (10.4)	Loss of 2H2O (lattice) + 1H2O (coord.water)	FeO
	2^nd	194–649	524.4	85.7 (85.6)	Loss of 2Cl + C21H17N5O2 ligand