Abstract

H. R. Dabhi¹, A. K. Rana¹* and D. K. Bhoi²

Stability constants and thermodynamic data of the chelates of Tetradentate Schiff– base of 4 - formyl-l-phenyl-3-methyl-2-pyrazolin-5-ones with ethelene diamine, hexamethelene diamine, benzedine with Mn2+, Co2+, Ni2+, Cu2+, and Zn2+ have been determined of 25° C and 35° C in 70:30 (v/v) dioxane – water media and 0.1 M KNO3 , using Calvin – Bjerrum technique as applied by Irving and Rossotti. The stability constants at both the temperatures is found to be Mn < Co < Ni < Cu > Zn for all systems. ΔG, ΔH, and ΔS for the complexation have been derived.

Formation constant; Thermodynamic parameters; Constraction energy; Potent iometric study; Mn2+; Co2+; Ni2+; Cu2+; Zn2+ chelates

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