Potentiometric and Thermodynamic Studies of Some Schiff-Base Derivatives of 4-Aminoantipyrine and Their Metal Complexes

Table 6

Thermodynamic functions for ML and ML₂ complexes of ligand (L₂) in 10% (by volume) ethanol-water mixture and 0.1 mol⋅dm⁻³ KCl.

M^𝑛+	𝑇/K	Gibbs energy/kJ⋅mol^−1		Enthalpy/kJ⋅mol^−1		Entropy/J⋅mol^−1⋅K^−1
		−Δ𝐺1	−Δ𝐺2	Δ𝐻1	Δ𝐻2	Δ𝑆1	Δ𝑆2
	298	41.82	38.46			243.82	229.45
Mn^2+	308	44.23	40.69	30.83	29.92	243.72	229.25
	318	46.70	43.05			243.82	229.45
	298	43.02	39.09			253.93	237.64
Co^2+	308	45.53	41.39	32.65	31.73	253.82	237.44
	318	48.01	43.83			253.93	237.65
	298	43.54	39.48			252.58	239.05
Ni^2+	308	45.99	41.87	31.73	31.75	252.38	239.04
	318	48.59	44.27			252.58	239.05
	298	44.39	40.34			264.61	248.00
Cu^2+	308	47.48	42.81	34.46	33.56	264.50	247.99
	318	49.68	45.30			264.62	248.05