Publications in Scientific Journals:
A. Moghimi, S. Sheshmani, A. Shokrollahi, M. Shamsipur, G. Kickelbick, H. Aghabozorg:
"Crystal structures and solution studies of two novel zinc(II) complexes of a proton transfer compound obtained from 2,6-pyridinedicarboxylic acid and 1,10-phenanthroline: Observation of strong intermolecular hydrogen bonds.";
Zeitschrift für Anorganische und Allgemeine Chemie,
631
(2005),
160
- 169.
English abstract:
The proton transfer compd. (phenH+)2(pydc2-), LH2, has been prepd. from 1,10-phenanthroline and 2,6-pyridinedicarboxylic acid (dipicolinic acid, pydcH2). Characterization was performed using soln. and solid phase CP/MAS 13C NMR and IR spectroscopy. The reactions of this adduct with ZnSO4.7H2O and Zn(NO3)2.4H2O give the complexes [Zn(pydc)2][Zn(phen)2(H2O)2].7H2O (1) and [Zn(phen)3]4(H(Hpydc)2)(NO3)7.26H2O (2), resp. These complexes were characterized by 1H and 13C NMR spectroscopy and single crystal X-ray anal. The complexes crystallize in the triclinic space group P.hivin.1 with Z = 2. The unit cell dimensions for complex 1 and 2 are: a = 9.9838(9) .ANG., b = 14.7483(13) .ANG., c = 14.8365(13) .ANG. and a = 12.640(4) .ANG., b = 15.855(5) .ANG., c = 21.830(7) .ANG., resp. In complex 1 pydc2- and phen are tri- and bidentate ligands, resp., and anionic [Zn(pydc)2]2- and cationic [Zn(phen)2(H2O)2]2+ fragments are formed simultaneously. In complex 2 three phen participate in complexation leaving hydrogen-bis(pyridine-2-carboxylate), (H(Hpydc)2)- as a supramol. anion. The fragments (H(Hpydc)2)-, 7NO3-, and 26H2O in complex 2 are joined together by extensive and strong H-bonding. The structure of 2 is composed of [Zn(phen)3]48+ and an anionic hydrogen bonded supramol. assembly with the formula {(H(Hpydc)2(NO3)7)8-.26H2O}n. The anionic species (H(Hpydc)2)- has a special position at the inversion center and one of the NO3- anions is disordered over the inversion center. Most of the hydrogen bonds in complex 2 represent strong H-bonding. The protonation consts. of the building blocks of the pydc-phen adduct, the equil. consts. for the reaction of pydc2- with phenanthroline, and the stoichiometry and stability of the ZnII complex with LH2 in aq. soln. were detd. by potentiometric pH titrn. The soln. study results support self-assocn. between pydc2- and phenH+ with a stoichiometry for the Zn(II) complex similar to that obsd. for the isolated cryst. complex.
Created from the Publication Database of the Vienna University of Technology.