SOLUTION STUDY AND CRYSTAL STRUCTURE OF A PENTACOORDINATE ZINC(II) COMPLEX WITH N,N″-bis-(2-HYDROXYBENZYL)-DIETHYLENETRIAMINE

The stability constants of Zn(II) complexes with N,N″-bis-(2-hydroxybenzyl)-diethylenetri-amine(H2L) were determined by potentiometric pH titration at 25°C and at 0.1 M KNO3 ionic strength. A neutral complex ZnL was synthesized. In addition to IR, and 1H NMR spectra, its structure was established by single crystal X-ray diffraction. The crystal is orthorhombic, of space group Pbca, with cell constants a = 17.865(4), b = 20.079(4), c = 9.598(2)Å, z = 8 and Dc = 1.461 g°Cm−3. The structure was solved and refined to R = 0.049 (Rw = 0.054). The coordination geometry around the zinc ion is trigonal-bipyramidal with a large distortion, exhibiting two nonequivalent phenolates.