Syntheses, structures, fluorescence sensing properties and white-light emission of lanthanide coordination polymers assembled from imidazophenanthroline derivative and isophthalate ligands

Abstract

Nine new lanthanide coordination polymers, namely, [La2(MPIP)2(1,3-bdc)3]n‧5nH2O (1) [Nd2(MPIP)2(1,3-bdc)3]n‧7nH2O (2), [Yb2(MPIP)(1,3-bdc)3]n(3), [Eu2(MPIP)2 (1,3-bdc)2(CH3COO)2]n(4), [Ln2(MPIP)2(1,3-bdc)2(NO3)2]n‧3nH2O (Ln = Tb (5), Gd (6)), [Ln2(MPIP)2(1,3-bdc)3]n‧2nH2O (Ln = Dy (7), Ho (8), Er (9)), MPIP = 2-(3-methylphenyl)imidazo(4,5-f)(1,10)-phenanthroline, H2(1,3-bdc) = benzene-1,3-dicarboxylic acid) have been synthesized under hydrothermal or solvothermal conditions and characterized by IR spectra, elemental analyses, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1–9 features 1D or 2D lanthanide isophthalate structures bearing large conjugated imidazophenanthroline derivative ligands. The thermal stabilities and luminescence properties of compounds 1–9 were investigated. Based on fluorescence sensing behavior, compounds 4 and 5 display a highly sensitive response toward Fe3+ ion through significant fluorescence quenching. Meanwhile, compound 5 can be used as an indicator to detect acidic and alkali environments. The white light emission was studied by heterogeneous physical mixing components of compounds 1, 4 and 5.