A mixed valence Tb(III)/Tb(IV) metal–organic framework: Crystal structure, luminescence property and selective detection of naproxen

Abstract A mixed valence terbium metal–organic framework (MOF), [Tb 2 (HCOO)(clhex)·2H 2 O)]·2H 2 O ( BUC-68 ) was obtained from the reaction of 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (H 6 clhex), formic acid, N,N-dimethylformamide (DMF) and the terbium salt under hydrothermal condition at 140 °C. The crystallographic analysis revealed that the three-dimensional BUC-68 is composed of two-dimensional [Tb 2 (clhex)·2H 2 O)] sheets linked by formic ligand. X-ray photoelectron spectra (XPS) analysis revealed that there were terbium (III) and terbium (IV) presented in BUC-68 . Thermogravimetric analysis (TGA) indicated that BUC-68 was stable up to 350 °C. Photoluminescent measurement showed that BUC-68 displays strong luminescence emission, which was arose from efficient ligand to metal energy transfer transitions. Finally, BUC-68 was utilized to conduct selective detect of naproxen (NPX) and some small organic molecules.