摘要:
In the pH range 2.7-3.7, [Fe(nta)(H2O)(2)] (1) reacted with Hbipy(+) and bipy to form the ternary complex, [Fe(nta)(bipy)] (2), which was also formed in the reaction between [Fe(nta)(H2O)(OH)](-) and Hbipy(+). The equilibrium constant determined spectrophotometrically agreed well with the kinetically determined value. Rate constants and corresponding activation parameters have been evaluated for different pathways leading to compound 2 and its dissociation. Bond dissociation appears to be important in the transition state. The greater thermodynamic stability of [Fe(nta) (benzohydroxamate)](-) (3) than 2 is a consequence of a-much greater rate of dissociation of compound 2 than of compound 3; formation rate constants for compounds 2 and 3 are similar. Copyright (C) 1996 Elsevier Science Ltd