Kinetics of the Ligand Exchange Reaction Between Tetradentate Schiff Base N,N'-ethylen-bis (salicylaldimine) and Cu(N,N'-propylen-bis(salicylaldimine)).

Visible spectrophotometry is used to study the kinetic of ligand exchange in the system Cu(salpn)/H2salen with or without triethylamine (NEt3) and H2O in acetonitrile solvent at 25 ± 0.1°C and 0.01 M NaNO3 (H2salen and H2salpn are N,N'-ethylen-bis(salicylaldimine) and N,N'-propylen-bis(salicylaldimine), respectively). It is found that the reaction rate is first-order with respect to Cu(salpn). In addition, the ligand exchange rate increases when NEt3 is added to the reaction mixture, as shown by a break in the kobs vs. [NEt3] plot. The effects of NEt3 and H2O on the ligand exchange rate are discussed, and reaction mechanism is proposed.