Novel supramolecular structures and theoretical calculation of Ag(I) and Zn(II) complexes based on a new dipyridylamine ligand

A new ligand dpa (dpa=3,4′-dipyridylamine) (1) has been designed and synthesized, which reacted with AgNO3 and ZnCl2, respectively, resulting in two new complexes, [Ag(dpa)2]NO3 (2) and [ZnCl2(dpa)2] (3). The complexes have been characterized by thermogravimetric analysis, spectroscopic techniques, and single crystal X-ray diffraction. 2 is one-dimensional (1D) helical chain structure formed by hydrogen bonding interaction, and the helices are connected by the electrostatic interaction between Ag(I) ions and O atoms from NO3−, leading to a two-dimensional (2D) supramolecular structure. For 3, the mononuclear [ZnCl2(dpa)2] is almost a regular tetrahedral configuration, which generates a dimeric structure constructed through N-H⋯Cl hydrogen bonds and π-π interactions between pyridine rings. The adjacent dimeric units extend further into two-dimensional rippled network structure by two kinds of hydrogen bonds (N-H⋯Cl, C-H⋯Cl) in different directions. On the basis of experiment, both two complexes were calculated by DFT-B3LYP/LANL2DZ in gaussian 03.