| Sonochemical synthesis and characterization of two Cd(II) based metal–organic frameworks as precursors for preparation of nano-materials |
| Paper ID : 1668-UFGNSM-FULL |
| Authors: |
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Farzaneh Afshari Azar * Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, Tehran, Iran |
| Abstract: |
| Nanoporous metal–organic frameworks (MOFs) have received considerable attention because of their potential applications in gas storage, separation, sensing, catalysis and drug delivery. Ultrasound irradiation is one of the simplest and most effective methods for preparation of nano or microstructures MOFs. In this simple, fast and green method molecules undergo a chemical reaction because of powerful ultrasound radiation (20 KHz–10 MHz). These extreme conditions induce chemical or physical changes and can also enhance the formation of nano-sized structures, mostly via an increase of crystallization nuclei. Thermal decomposition of MOFs under various conditions has been widely studied with the aim to prepare metal oxide nanostructures with desire sizes and morphologies. In this study, two Cd(II) based metal–organic frameworks (TMU-8 and TMU-9 ) based on a V-shaped flexible dicarboxylate ligand 4,4'-oxybis(benzoic acid) (H2oba) and the N-donor ligands, 4-bpdb and 4,4'-bipy,(4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and 4,4'-bipy =4,4'-bipyridine) have been synthesized via sonochemical method and the effect of ultrasonic irradiation time, power and concentration of initial reagents on shape and size of particles were investigated. Ultrasonic syntheses of TMU-8 and TMU-9 were carried out in an ultrasonic bath at ambient temperature and atmospheric pressure for 30, 60 and 90 min The resulting powder was isolated by centrifugation, washed with DMF three times and dried in air for characterization. The morphology and size of TMU-8 and TMU-9 were investigated using scanning electron microscopy (SEM) by changing three parameters; sonication time, sonication power and concentration of starting materials as well as control of nucleation. Almost in all cases nanoplate was the dominant morphology. Meanwhile, increasing power of ultrasonic irradiation led to uniformly sheet-like morphology for TMU-8 and nanoparticles ranging from 20 to 100 nm in the case of TMU-9. Finally, by thermolysis of these MOFs at 550oC under air atmosphere CdO nanoparticles were obtained. |
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| Status : Paper Accepted (Poster Presentation) |
