Three hydrogen-bonded nanotubular zinc(II) complexes of N-(9-anthracenyl)-N′-(4-pyridyl)-urea

Three hydrogen-bonded nanotubular zinc(II) complexes of a monodentate ligand N-(9-anthracenyl)-N′-(4-pyridyl)urea (L), [Zn(OAc)2L2]∙H2O (1), [ZnBr(OAc)L2]∙H2O (2) and [ZnCl(OAc)L2]∙4H2O (3), were synthesized and structurally characterized. In the complexes, the central metal ion is tetrahedrally coordinated by the pyridyl nitrogen atoms of two ligands and different anions, while the urea groups of the ligands self-associate into the typical urea tape through R21(6) hydrogen bonds, which are essential for the formation of the nanotubes. The fluorescence properties of ligand L and the complexes were studied in the solid state at room temperature.