A Route to Bimodal Micro-Mesoporous Metal-Organic Frameworks Nanocrystals

To overcome the pore size constraints (pore size < 2 nm) of crystalline microporous metal organic frameworks (MOFs), one can either reduce crystal size or create mesopore channels in the MOF crystals. Our approach does both, using a solvothermal nonionic surfactant-templated assembly of microblocks in the presence of acetic acid, which not only generates well-defined mesopore channels within the microporous MOF nanocrystals but also gives high crystallinity. Two examples were selected to illustrate our approach using [Cu-3(BTC)(2)]- and [Cu-2(HBTB)(2)]-based MOFs (H3BTC = 1,3,5-benzenetricarboxylic acid; H3BTB = 1,3,5-Tris[4-carboxyphenyl]benzene).