Synthesis, Structure And Characterization Of Catalysis Carboxyester Hydrolysis Of Macrocyclic Triamine Complexes

The macrocyclic triamines and their derivatives have been the interesting field for the chemistry because of their metal complexes with diverse applications in bioinorganic systems, magnetic systems and catalytic systems. Along this line,we synthesized the macrocyclic triamine ligand 1,4,7-triazacyclododecane (TACD) that was reported in rarely literatures and its six new derivative ligands.These new ligands are very important for the studies of macrocyclic triamine compounds.In this work, twenty nine metal complexes containing these ligands have been synthesized and characterized by elemental analysis, IR spectra, UV-visible spectra and thermal gravimetric analyses,etc.Single-crystal structures of eleven complexes have been determined by X-ray diffraction. Although these complexes are mono-nuclear, there are abundant hydrogen bonds in complexes 2, 3, 5 and 18, resulting in some novle two-dimensional supramolecular network structures.The complexes 2 and 3 formed a network with 12-membered rings and 4-membered rings. The complex 5 assembled into a supramolecular structure with beautiful channels.The complex 18 (?) formed (?)-a frameworks with novle regular trigonal water molecule cluster.In addition, we determined the protonation constants of the ligand TACD and equilibrium constants of Cu(II) and Zn(II) complexes with TACD by pH potentiometer titration, and studied the kinetics of p-nitrophenyl acetate (NA) hydrolysis catalyzed by the Cu(II) and Zn(II) complexes with TACD and complexes 20～23 through spectrophotometrically.The results suggest the catalysis of the metal complexes with ligand L~3 is better than that of the same metal complexes with TACD, which indicated the hydroxypropyl of ligand L~3, after coordinating to metal, can be activated and changed into oxygens anion with stronger nucleophilic reactivity.