Thermodynamics of stability constant of binary complex of nicotinamide with Mn++

Abstract

The stability constants of the binary complexes of Mn2+ with nicotinamide (NA) were determined from potentiometric pH titrations data at 15.0, 25.0 and 35.0degreesC and I = 0.1,0.2,0.4 mol L-1 (NaClO4). The formation of binary 1: 1, 1:2 NA-Mn complexes at three different temperatures and the influence of three different ionic strength on their stability were reported. The thermodynamic parameters (DeltaG(f)degrees, DeltaS(f)degrees, DeltaH(f)degrees) for the complex formation reaction were estimated from stability constant at different temperatures.