Supramolecular assemblies formed by cooperative metal coordination and dimerization of the N-(2-pyirimidyl)-N '-(3-pyridyl)urea ligand via hydrogen bonding

The supramolecular structures of two metal complexes, [CoCl2L2] (1) and [ZnCl2L2] (2), where L = N-(2-pyrimidyl)-N'-(3-pyridyl)urea, are reported. The complexes feature zigzag chains formed by the self-dimerization of the ligand via a pair of N-urea-H center dot center dot center dot N-pyrimidyl hydrogen bonds with the R-2(2)(8) motif. Only the pyridyl nitrogen atom coordinates to the metal atom whereas the two pyrimidyl N donors are involved in intra- and intermolecular hydrogen bonding interactions. The coordinated Cl atoms do not form any hydrogen bonds with the urea NH groups. The dimerization of the ligand (K = 90 M-1) was investigated by H-1 NMR spectroscopy.