SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF COPPER(II) COORDINATION POLYMERS FROM ETHYL AMINOMETHYLENECYANOACETATE DERIVATIVES

The reaction of copper(II) acetate with ethyl aminomethylenecyanoacetate derivatives 10 (H2L4) or 13 (H2L5) provides thermally highly stable products, that are insoluble in noncoordinating solvents. Single-crystal X-ray diffraction of the copper(II) chelates 11 ([CUL4]infinity) and 14 ([CuL5]infinity) established unequivocally the structures of the coordination polymers. Initially, coordinatively unsaturated copper(II) intermediates 12 and 15 are formed, disposing two CN donor groups in the equatorial plane of the chelates. Thus the bidentate building blocks 12 and 15 undergo spontaneous self-organization, by performing coordination of CN groups on the axial positions of the intermediary chelates, leading to coordinative saturation of the copper(II) centers. The supramolecular 2D geometry of the coordination polymers 11 and 14 depends basically on the lateral groups of the chelate ligands.