Syntheses and crystal structures of zinc(II) complexes with three kinds ofpiperidine carboxylic acids

Zinc(II) complexes with DL-piperidine-2-carboxylic acid (Hpipe-2), DL-piper idine 3-carboxylic acid (Hpipe-3), and piperidine-4-carboxylic acid (Hpipe- 4):ZnCl2(Hpipe 2)(2), ZnCl2(Hpipe-3)(2)(H2O)(3), and ZnCl2(Hpipe-4) have be en prepared and characterized by means of IR spectra and thermal analysis. The crystal structures of [ZnCl2(Hpipe-3)(2)]. 3H(2)O and [ZnCl2(Hpipe-4)] have been determined by X-ray diffraction. The crystal of [ZnCl2(Hpipe-3)(2 )]. 3H(2)O is monoclinic with the space group P2(1)/c. The zinc atom is in a tetrahedral geometry, ligated by two carboxylato oxygen atoms and two chl orine atoms. The crystal of [ZnCl2(Hpipe-4)] is triclinic with space group P (1) over bar. This complex consists of a binuclear molecule bridged by tw o carboxylato oxygen atoms. The zinc atom is in a tetrahedral geometry liga ted by two carboxylato oxygen atoms and two chlorine atoms. (C) 2001 Elsevi er Science B.V. All rights reserved.