Green Synthesis And Structure Modification Of Metal-1,3,5-benzenetricarboxylate Frameworks

Metal-organic frameworks (MOFs), also known as porous coordination polymers have recently attracted considerable attention because of their diverse fascinating topologies, pore size tenability and extensive uses in lots of fields such as catalysis, adsorption, chemical sensing and so on. While research on new, purpose-designed MOFs is still developing at high pace, functionalization and/or surface modification of the frameworks are increasingly being considered as versatile and possibly more powerful alternative approaches to boost application performance. Such modifications can alter the framework chemically by the infusion of cargo molecules, substitution of the linker or the metal, addition of new functional groups, or application of surface coatings.We study to green synthesis and structure modification of MOFs which the linker is1,3,5-benzenetricarboxylic acid (H3BTC).We employed vapor-assisted aging (VAG), which is a simple, mild and green preparation method, to obtain metal-organic frameworks (MOFs) from metal oxides and metal carbonates with high lattice energy at room temperature. Dozens of grams of high crystalline HKUST-1(1) were produced easily and quantitatively by water vapor-assisted aging of pre-ball milled reactants:1,3,5-benzenetricarboxylic acid (H3BTC), CuO, NH4Cl (5wt.%) and DMF (100μL), for6hours at room temperature. Interestingly, under similar conditions as above, the absence of DMF led to a one-dimensional coordination polymer[Cu(HBTC)(H2O)3]. And surprisingly,[Cu(HBTC)(H2O)3] could be transformed into HKUST-1under DMF VAG within1hour, which shows its high reactivity in VAG reaction. Further, ethanol and water VAG of pre-ball milled terbium carbonate, H3BTC and NH4Cl (5wt.%), would give a porous3-dimensional(3-D)[RE(BTC)(H2O)] and a3-dimensional(1-D)[RE(BTC)(H2O)6] respectively. When rare earth carbonates are replaced by RE2O3, it takes3days to react with H3BTC to form[RE(BTC)(H2O)6]. Likewise,[RE(BTC)(H2O)6] can be transformed into porous [RE(BTC)(H2O)] in ethanol vapor within30hours.We can select the suitable microMOFs HKUST-1. Adding some template (salt), we can get the mesopores by Mechanochemical method which remove from the template. The hierarchically meso-and microporous MOFs can synthesized with a template.Construction of core-shell MOFs by using rear-earth salts and H3BTC in solvent method. Eu based coordination polymers were prepared via a previously reported solvent method using H3BTC and Eu(NO3)3-6H2O. Consecutive solvent reactions of the secondary precursors (H3BTC and Tb(NO3)3-6H2O) in the presence of the initially prepared Eu-based coordination polymers gave a [Eu(BTC)(H2O)6](core)@[Tb(BTC)(H2O)6](shell) structure. A series of rare-earth the core-shell structures [RE(BTC)(H2O)6]@[RE(BTC)(H2O)6] were then react with precursors H3BTC and RE(NO3)3-6H2O(Re=Sm, Gd, Dy) consecutively.