Coordination compounds of Cd(II) with several bidentate- NN′ and tridentate- NN′ N nitrogen donor ligands. 113Cd NMR studies of monomeric compounds containing nitrogen donor atoms

Abstract

Reaction of CdCl 2 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 absolute ethanol yields [CdCl 2( NN′)] ( NN′ = deae ( 1), deat ( 2)), [CdCl 2( bdmae)] ( 3), and [CdCl( ddae)] 2[CdCl 4] ( 4). The Cd(II) complexes have been characterised by elemental analyses, conductivity measurements, IR, 1H, 13C{ 1H} and 113Cd NMR spectroscopies, and X-ray diffraction methods. 1H and 113Cd NMR experiments at variable temperature for 3 and 4 show that dynamic processes are taking place in solution. We report the measurements of 113Cd NMR chemical shift data for complexes 1- 4 in solution. X-ray crystal structures for complexes 2 and 3 have been determined. The Cd(II) is coordinated to the deat ligand, in 2, by one nitrogen atom of the pyrazolyl group and one nitrogen atom of the amine. It finishes a tetrahedral geometry with two chlorine atoms. The bdmae ligand is linked to Cd(II), in 3, by two nitrogens atoms of the pyrazolyl groups and one amine nitrogen, along with two chlorine atoms, in a distorted trigonal bipyramidal geometry.