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

Reaction of CdCl₂ 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 CdCl₂(NN′)] (NN′ = deae (1), deat (2)), CdCl₂(bdmae)] (3), and CdCl(ddae)]₂CdCl₄] (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.