A unique multifunctional cluster-based nano-porous Terbium organic material: Real-time detection of benzaldehyde, visually luminescent sensor for nitrite and selective high capacity capture of Congo Red

In this work one rigid asymmetrical tricarboxylate ligand p-terphenyl-3,4",5-tricarboxylic acid (H3L) ligand has been synthesized, one unique nano-porous Terbium luminescent metal-organic framework (ITb(L)(H(2)0) (DMF)]"DMF}(n) (1) has been prepared using solvo-thermal techniques. Structural analysis demonstrated that these di -nuclear Tb(2)0(2) clusters are bridged via rigid ter-phenyl backbones of L3- generating one unique three-dimensional(3D) cluster-based nano-porous framework of 1. In 1 nano porous channels with dimensionality of 9.788(1) A x 19.209(3) A can be found along the crystallographic a direction. According to a PLATON calculation, there exists approximately 33.7% of the crystal volume (6286.8 A(3) potential solvent areas) accessible to guest molecules. Powder X-ray diffraction (PXRD) determination also confirms pure phases of 1. Photo-Luminescent experiments suggested that 1 shows real-time sensitive sensing for benzaldehyde. Addition of only 1 mu 1 benzaldehyde to ethanol emulsion of 1, the resulting emission intensity was attenuated by approximately 52.07%. It is also noted that the fluorescent intensity of 1 can be efficiently resumed through the fast and simple technique of washing the benzaldehyde-1 sample by water. Meanwhile 1 also showed high selectivity, fast detection time (<1 min), excellent sensitivity (detection limit, 0.54 M) and visual detection for nitrite over other anions in aqueous solutions. The quenching efficiency of 1 by nitrite is not only linearly correlated with nitrite concentration in the wide range of 3-1000 mu M, but also linearly correlated with reaction time, which is scarcely reported in the previous photo -luminescent sensors for nitrite. Moreover, 1 can selectively adsorb organic dye Congo Red (CR) possessing a high absorption amount of 636.94 mg/g in water solutions. Time dependence for CR adsorption on 1 can be well depicted by using the pseudo second-order kinetic model, which is consistent with chemisorption mechanism. Therefore 1 also represents a unique multi-functional 3D cluster-based nano-porous Terbium metal organic material as realtime detection of benzaldehyde, visual chemosensor for nitrite and high amount absorption of CR. (C) 2017 Elsevier Ltd. All rights reserved.