Supramolecular assemblies formed by cooperative metal coordination and dimerization of the N-(2-pyrimidyl)-N′-(3-pyridyl)urea Ligand via hydrogen bonding

The supramolecular structures of two metal complexes, [CoCl ₂L₂] (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···N_pyrimidyl hydrogen bonds with the R₂²2(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 ¹H NMR spectroscopy.