Self-assembly of two fluorescent supramolecular frameworks constructed from unsymmetrical benzene tricarboxylate and bipyridine

Two new supramolecular compounds, Ag(4,4′-bipy)]_n Ag(HBTC)]_n (1) and Cu(H₂BTC)(2,2′-bipy)] (2) (HBTC/H₂BTC = 1,2,4-benzenetricarboxylate, 4,4′-bipy/2,2′-bipy = 4,4′/2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR spectra, ultraviolet-visible diffuse reflection integral spectra (UV-Vis DRIS), fluorescent spectra, thermogravimetric analysis and single crystal X-ray diffraction analysis. It is noteworthy that there were two kinds of one-dimensional stairs-chain including cationic Ag(4,4′-bipy)]_n chain and anionic Ag(HBTC)]_n chain in 1. Furthermore, a two-dimensional double layer supramolecular framework was constructed through coordination bonds, hydrogen bonds, π-π stacking interactions and Ag?O weak coordinative interactions. The one-dimensional supramolecular chain of 2 was built from combining mononuclear Cu(H₂BTC)(2,2′-bipy)] by inter- and intra-molecular hydrogen bonding interactions. Additionally, the two complexes exhibit intense blue or olivine luminescence at room temperature.