Luminescent metal–organic frameworks with a 2-(4-pyridyl)-terephthalic acid ligand for detection of acetone

Three metal-organic frameworks (MOFs), [Zn(pta)(H2O)](n) (1) {[Zn(pta)]H2O}(n) (2) and {[Cd(pta)]H2O)}(n) (3) [H(2)pta = 2-(4-pyridyl)-terephthalic acid], were isolated by hydrothermal synthesis. Single-crystal X-ray analysis reveals that compound 1 shows a 2D layer-like network, while compounds 2 and 3 feature different 3D frameworks with Schlafli symbols of {4<^>2.6.8<^>3} and {4<^>6.6<^>4} respectively, in which the deprotonated pta(2-) ligands are indicative of diverse coordination modes. The thermostability, water stability and luminescent properties of 1-3 were investigated in the solid state at room temperature. It is noteworthy that 3 shows high selectivity for the detection of acetone in different solvents via a fluorescence quenching mechanism. By virtue of its excellent detection efficiency, applicability in water and reusability, compound 3 can be a promising fluorescent material for practical acetone sensing.