The syntheses, structures and photoluminescence properties are reported for two new binuclear cyclometalated iridium(III) complexes, [Ir2(ppy)4(L)] (1) and [Ir2(F2-ppy)4(L)] (2) (ppy=2-phenylpyridine, F2-ppy = 2-(2,4-difluorophenyl)pyridine, H2L=N,N′-bis(2-hydroxynaphthyl methylidene)-2-hydroxy-1,3-propanediamine. X-ray crystal diffraction shows that L ligands adopt a tetradentate mode to bridge ir(III) ions to form binuclear structures. There are π-π stacking interactions between the binuclear structures, which results in the formation of 3D supramolecular networks. UV–vis absorption spectra and photoluminescence spectra show that the introduction of F− groups in the benzene rings of ppy ligands causes blue shift.

In this paper, a new fluorescence chemosensor 3-[(2-hydroxy-1-naphthyl) methylideneamino]benzoic acid (L) was designed, synthesized and characterized. Fluorescence spectrum and UV–vis spectra show that L exhibits a highly selective and sensitive recognition for HCO3-/CO32- in N,N′-dimethylformamide/water (DMF/H2O, 100/1-10/1, v/v) in pH range of 5-14. The competitive experiments and reversible tests prove the good performance of L. The Job′s plot, 1H NMR titration, and electrospray ionization mass spectrometry (ESI-MS) results show that L and HCO3-/ CO32- form 1:1 complexes. The probable mechanisms and the proposed binding modes were discussed.