Synthesis of a Layered Terbium(III) Metal-Organic Framework with bis(pyrazol-1-yl)Methane-4,4′-Dicarboxylic Acid and its Sensory Properties as a Biomarker for Spore-Forming Bacteria

A new layered metal-organic framework (MOF) {[Tb2(H2O)2L3]·H2O·CH3CN}n is obtained by the solvothermal synthesis from terbium(III) nitrate and bis(pyrazol-1-yl)methane-4,4′-dicarboxylic acid (H2L). The compound is a layered framework formed of two types of binuclear secondary building units {Tb2} linked by carboxylate groups of L2– ligands. The layers are stabilized by intermolecular hydrogen bonds and contain channels occupied by water and acetonitrile molecules. The thermogravimetric analysis shows a high thermal MOF stability after the removal of guest molecules up to 400 °C. The luminescence quantum yield is 25%, and the excited-state lifetime is 1.19 ms. The high selectivity is demonstrated of the luminescence sensory response of the MOF suspension in acetonitrile to 2,6-pyridinedicarboxylic acid (DPA), a key biomarker of spore-forming bacteria.