A Luminescent Terbium MOF Containing Hydroxyl Groups Exhibits Selective Sensing of Nitroaromatic Compounds and Fe(III) Ions

A new 3D porous Tb(III)-ion based PMOF, {[Tb(L)(DMA)]center dot(DMA)center dot(0.5H(2)O)} (1) (where L = L3-, H3L = 3'- hydroxybiphenyl-3,4',5-tricarboxylic acid), with uncoordinated hydroxyl groups decorating the pores has been solvothermally synthesized in moderate yield. The hydroxyl groups act as potential interaction sites to sensitize the luminescence output of the Tb3+ ion. Luminescence studies reveal that the PMOF can selectively and reversibly sense nitroaromatic compounds and Fe(III) ions in DMF suspension through fluorescence quenching observable under UV light. The probable mechanisms for such sensing processes are, for the nitroaromatic compounds, the host-guest interactions with the PMOF and, for Fe3+ ion, the competitive absorption of excitation energy.