STOICHIOMETRY AND STRUCTURE OF TETRAFLUOROBORATE COMPLEXES OF Zn(II) WITH ISOMERIC PHENYLENDIAMINES

Abstract

The tetrafluoroborate complexes of Zn (II) with o-, m- and p-phenylenediamines (FDA) have been synthesized. The investigation of the stoichiometry and the structure of synthesized compounds have been carried out by different physicochemical methods. In accordance with the results of element analysis and atomic absorption spectroscopy the compounds of general formula Zn(FDA)4(BF4)2have been obtained for m- and p-isomers independently of synthesis method. In the case of o-FDA at a synthesis without a solvent and components ratio 1:6 the complex Zn(o-FDA)2(BF4)2 has been synthesized. The lowering of ratio Zn:o-FDA to 1:4 and the ethanol use as a solvent resulted in two water molecules inclusioninto inner coordination sphere [Zn(o-FDA)2(H2O)2](BF4)2.The molar conductivity measurement of dimethylformamide solutions of synthesized compounds shown that complexes are the three-ionic electrolytes of general formula [Zn(FDA)4](BF4)2for m- and p-FDA and [Zn(о-FDA)2](BF4)2 and [Zn(о-FDA)2(H2O)2](BF4)2for o-FDA.The centers of the organic ligand coordination and the outer sphere character of the BF4-bonding have been found by IR spectroscopy. It was determined the nature of the organic ligand and synthesis method determine the stoichiometry and structure of complexes.

Keywords

• тетрафтороборат, фенілендіамін, комплекс