Chiral Mixed Ligand Complexes as Catalysts in the Hydrolysis of Esters

Chiral mixed ligand (CML) metal complexes of the type MLL ' ·xH2O (x = 1 or 2), where M is Co(II)/Ni(II), L is deprotonated 8-hydroxyquinoline and L' is a deprotonated poly dentate chiral secondary ligand have been synthesized. The metal complexes have been characterized on the basis of elemental analysis and various physicochemical techniques. The molar conductance values of the complexes in methanol at 10 -3 M concentration were very low (<1), indicating their non-electrolytic nature. The observed μeff values are suggestive of the tetrahedral/octahedral geometry for the Co(II) complexes and an octahedral geometry for the Ni(II) complex. The magnetic moments of the compounds investigated are in agreement with the conclusions based on spectral findings. Hydrolysis of methyl acetate and ethyl acetate was studied by using the complexes as homogeneous catalysts. The rate constants have been obtained by using different catalysts at various temperatures. The activation energy (E) was calculated from the Arrhenius plots. The changes in the enthalpy of activation ( �H � ), entropy of activation ( �S � ) and free energy of activation ( �G � ) were also calculated. A probable