Vol. 8, Issue 1 (2019)

Stability constants of transition metal complexes of 5-methyl-4-phenyl-2-aminothiazole and R-Substituted salicylaldehyde (R-H,4CH3 and 5-Br) i.e. N-(Salicylidence)-5-methyl-4phenyl-2-aminothiazole (SMPAT), N-(4-methylsali-cylidene) 5-methyl-4-phenyl-2-aminothiazole (4MSMPAT) and N-(5-Bromosalicylidine)5-methyl-4-phenyl-2-aminothiazole. (5BSMPAT) has been determined in ethanol-water 75:25 (v/v) medium at different ionic strength. I = 0.1, 0.08, 0.06 and 0.04 M (NaNO3) and at different temperature (35 and 450C) using Bjerram PH – metric technique as adopted by Irrving-Rossoti. The formation constants (logn) have been calculated using Bjerrum half integral n and graphical method. The stability constants of metals CoII, NiII, CuII and ZnII with SMPAT, 4MSMPAT and 5BSMPAT have been found to be proportional to their ionic strength and inversely proportional to the temperature. (-H) and (-G) values shows spontaneous and exothermic reactions respectively between the metal and ligand. (S) values observed in all cases.