trans-bis(saccharinato)zinc and -cadmium complexes with N-(2-aminoethyl)piperazine: Synthesis, crystal structures and IR spectra

The reactions of N-(2-aminoethyl)piperazine (aeppz) with tetraaqua-bis(saccharinato)zinc(II) and -cadmium(II) in ethanol solution yield the new complexes trans- [Zn(sac)(2) (aeppz)(2)] (1), and trans[Cd(sac)(2)(aeppz)(2)] (2) (sac = saccharinate), respectively. The complexes were characterized by elemental analyses, IR spectroscopy and X-ray crystallography. Both complexes 1 and 2 are mononuclear of C-i symmetry. The zinc(II) and cadmium(II) ions are coordinated by two neutral aeppz ligands and two sac anions in an elongated distorted octahedral environment. The aeppz ligand acts as a bidentate N, N' donor through the central heterocyclic N atom and the N atom of the aminoethyl group, while the sac ligand is O-coordinated via the carbonyl 0 atom. The packing of the molecules in the crystals in both complexes is consolidated by arene pi-pi stacking interactions between the sac rings and by intermolecular hydrogen bonds involving the amine groups of aeppz and the sulfonyl oxygen atoms of the sac ligands.