Specific fluorescence sensing of hydrogen sulphide by an azide functionalized Zr(IV) MOF with DUT-52 topology

In this work, we synthesized an azide functional group containing Zr(IV) based metal-organic framework (MOF) with DUT-52 (DUT = Dresden University of Technology) topology via solvothermal process. Acetic acid was used as a modulator to increase the crystallinity. The synthesized compound (1) was activated by exchanging occluded molecules with methanol and heating at 80 degrees C for 5 h. Both 1 and activated compound (1 ') were characterized by X-ray powder diffraction (XRPD), Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA). Both 1 and 1 ' are thermally stable up to 320 degrees C and chemically stable in solvents like methanol, 1 (M) HCl and water. The Brunauer-Emmett-Teller (BET) surface area of 1 ' was found to be 505 m(2) g(-1). The data from fluorescence experiments suggested that 1 ' exhibits sensitive and selective detection of H2S in aqueous medium. The limit of detection (LOD) value was found to 0.50 mu M. This value lies in the lowest range of H2S detection by known MOFs. Moreover, the possible mechanism behind the enhancement of fluorescence intensity after addition of Na2S in 1 ' was also examined.