cis-bis(Saccharinato)cobalt(II) and -zinc(II) complexes with 2-dimethylaminoethanol: syntheses, crystal structures, spectroscopic and thermal studies

Abstract

2-Dimethylaminoethanol (dmea) reacted with tetraaqua-bis(saccharinato) cobalt(II) and -zinc(II) in n-butanol to yield the new complexes cis-[Co(sac)(2)(dmea)(2)] (1), and cis-[Zn(sac)(2)(dmea)(2)] (2) (sac=saccharinate). The complexes were characterized by elemental analyses, IR spectroscopy, DTA-TG and X-ray crystallography. Both complexes are isomorphous and crystallize in the monoclinic space group P2(1)/c. The cobalt(II) and zinc(II) ions are coordinated by two neutral dmea ligands and two sac anions in a distorted octahedral environment. The dmea ligand acts as a bidentate N, O donor through the amine N and hydroxyl O atoms, while the sac ligand exhibits non-equivalent coordination, behaving as an ambidentate ligand; one coordinates to the metal via the carbonyl oxygen atom, while the other is N-bonded. The packing of the molecules in the crystals of both complexes is achieved by aromatic pi(sac)-pi(sac) stacking interactions, C-H-...pi interactions and weak intermolecular C-(HO)-O-... hydrogen bonds involving the methyl groups of dmea and the sulfonyl oxygen atoms of the sac ligands. IR and UV spectra and thermal analysis are in agreement with the crystal structures.