Synthesis And Characterization Of Coordination Compounds Constructed From Malonic Acid Containing Ketenedithioacetal Groups And Cadmium Ion

Coordination compounds, especial coordination polymers have received extensivelyattention in recent years, not only because of their various intriguing topological structures butalso because of their potential applications as new functional materials in host-guest chemistry,molecular recognition, ion exchange, heterogeneous catalysis, non-linear optical (NOL) andso on. In this research, 3 new coordination compounds have been designed and synthesizedwith Cd(â…¡) ion and a kind of new dicarboxylic acid containing ketenedithioacetal groups,nitrogen donor ligands (pyridine, 1,10-phenanthroline) by means of conventional solutionreaction. The structures of the coordionation compounds have also been characterized by IRand X-ray diffraction.1. In coordination compound [Cd(Py)₃(Hdyma)₂](Py=pyridine, H₂dyma=2-[1,3]-dithiolan -2-ylidene malonic acid), 1, the local environment of cadmium(â…¡) ion exhibits tetragonal geometry, coordinated with three nitrogen atoms from pyridine and two carboxylato-oxygen atoms from Hdyma. There are six non-coordinated oxygen atoms with sexidentate ligand feature. It exists cathodal channel approximating to octagon geometry along the c axis.2. In coordination compound [Cd(Hdyma)₂(phen)(H₂O)](H₂dyma=2-[1,3]-dithiolan -2-ylidene malonic acid, phen=1,10-phenanthroline), 2, the cadmium atom is seven-coordinated through coordination to five oxygen atoms of two cheating carboxylate groups of two Hdyma ligands, one water molecule and two nitrogen atoms of one chealting phen ligand. Furthermore, There exists hydrogen bond interactions between oxygen atoms from coordinated water molecule and uncoordinated carboxylate groups.3. Coordination compound [{Cd(DYM)(H₂O)₂}·H₂O]n(DYM=2-[1,3]-dithian-2-ylidene malonic acid) 3 is a 2D layered polymer with Cd6 hexagon building units. The cadmium ion adopts a heptacoordination environment and exhibits a mono-capped octahedral geometry. In complex 3, each DYM ligand adopts s special μ5-bridging mode linking three Cd(â…¡) atoms and each Cd(â…¡) atom participates in forming three four-membered, six-membered and eight-membered chealthing rings. It is noteworthy that there are a lot of hydrogen bond interactions between carboxy groups and water molecules and weak C-H…S hydrogen bonds between the 1,3-dithiocyclohexyls of two adjacent DYM ligans.