COPPER(II) AND ZINC(II) COMPLEXES OF N,N-BIS(BENZIMIDAZOLE-2-YLMETHYL)-AMINE - SYNTHESIS, FORMATION-CONSTANTS AND THE CRYSTAL-STRUCTURE OF [ZNLCL](2)] - MEOH - CATALYTIC ACTIVITY OF THE COMPLEXES IN THE HYDROLYSIS OF THE PHOSPHOTRIESTER 2,4-DINITROPHENYL-DIETHYL PHOSPHATE

The copper(II) and zinc(II) complexes of N,N-bis(benzimidazole-2-ylmet hyl) amine (L) have been prepared and the crystal structure of [ZnLCl2 ]. MeOH determined. The complex is five-coordinate with a distorted sq uare pyramidal geometry on zinc.:Two pyridine nitrogen donors from the imidazole groups, the secondary amino group and one chloride act as i n-plane donors with the axial site occupied by chloride. The zinc(II) lies some 0.65 Angstrom above the basal plane. The stepwise protonatio n constants of the ligand have been obtained, log K-11 = 5.638(3) and log K-12 = 10.12(1) and the stability constants (log beta(1mh)) for th e copper(II) and zinc(II) complexes determined using 50% MeOH-H2O as s olvent. The hydroxoaqua complexes [ML(OH) (OH2)](+) show only slight c atalytic activity in the hydrolysis of the phosphotriester 2,4-dinitro phenyl diethyl phosphate, (C) 1998 Elsevier Science Ltd. All rights re served.