The binding properties of ethylene-N,N-dianthranilate(EDA)and Ni(II)were studied by difference UV-Vis in 0.05 M Tris-HCl buffer(pH 7.4).The stoichiometric ratio of EDA to nickel(1:1)was confirmed and the conditional binding constant(logKNi-EDA=12.33±0.06)was obtained.In addition,an interesting tetranuclear complex[Ni4(EDA)4]·2CH3CH2OH·9H2O was obtained unexpectedly in alcohol-water solution and characterized by X-ray crystallography and electrospray ionization mass spectra(ESI-MS).It is found that EDA acts as a pentadentate ligand and performs a chelating-bridging coordination mode.
