Synthesis, crystal structures and photophysical properties of novel tetranuclear cadmium(II) Schiff-base complexes

The synthesis and structural characterisation of some new tetranuclear cadmium(II) Schiff-base complexes were described. Reaction of the hexadentate Schiff-base ligands (H2L) with an excess of cadmium(II) acetate, Cd(OAc)2, furnished novel tetracadmium complexes of the general formula [Cd4(L)2(OAc)4], which exhibit an interesting three-dimensional cage-like structure of four ligand-supported cadmium atoms. All of the complexes were fully characterised by spectroscopic (FTIR, NMR and FAB MS) methods and their molecular structures were confirmed by single-crystal X-ray analysis. The X-ray crystal structures of these tetranuclear Schiff-base complexes represent the first structurally characterised examples of this kind for the cadmium triad. These new complexes were found to display rich photophysical properties and they all exhibited low-temperature phosphorescence in the frozen state. KGaA, 2005.