Coordination compounds of Zn(II) with several bidentate-NN′ and tridentate-NN′N nitrogen donor ligands

Reaction of ZnCl2 with N-alkylaminopyrazole ligands 1-[2-(ethylamino)ethyl]-3,5-dimethylpyrazole (deae), 1-[2-(tert-butylamino)ethyl]-3,5-dimethylpyrazole (deat), bis-[(3,5-dimethylpyrazolyl)methyl]ethylamine (bdmae), and bis-[(3,5-dimethylpyrazolyl)ethyl]ethylamine (ddae) in ethanol yields [ZnCl2(NN′)] (NN′ = deae (1), deat (2)), [ZnCl2(bdmae) (3), and [ZnCl(ddae)]2[ZnCl4] (4). These Zn(II) complexes have been characterised by elemental analyses, conductivity measurements and IR and 1H and 13C{1H} spectroscopy. The NMR studies proved the flipping of the six-membered ring. The solid of complexes 1, 2, and 4 were determined by X-ray diffraction studies. The Zn(II) is coordinated to the deae and deat ligands by one nitrogen atom of the pyrazolyl group and one nitrogen atom of the amine, and to bdmae ligand by two nitrogen atoms of the pyrazolyl groups, along with two chlorine atoms in a tetrahedral geometry. With ddae ligand, the Zn(II) is coordinated by two nitrogens atoms of the pyrazolyl groups and one nitrogen atom of the amine, along with one chlorine atom, in a tetrahedral geometry.

Molecular and ionic Zn(II) complexes of several N-alkylaminopyrazole ligands (NN′ and NN′N) have been prepared and characterised. Several analytical and spectroscopic studies of the complexes allowed us to determine the coordination of the ligands to the metal centre.Figure optionsDownload as PowerPoint slide