Uniform single-crystal mesoporous metal-organic frameworks.

The synthesis of mesoporous metal-organic frameworks (meso-MOFs) is desirable as these materials can be used in various applications. However, owing to the imbalance in structural tension at the micro-scale (MOF crystallization) and the meso-scales (assembly of micelles with MOF subunits), the formation of single-crystal meso-MOFs is challenging. Here we report the preparation of uniform single-crystal meso-MOF nanoparticles with ordered mesopore channels in microporous frameworks with definite arrangements, through a cooperative assembly method co-mediated by strong and weak acids. These nanoparticles feature a truncated octahedron shape with variable size and well-defined two-dimensional hexagonally structured (p6mm) columnar mesopores. Notably, the match between the crystallization kinetics of MOFs and the assembly kinetics of micelles is critical for forming the single-crystal meso-MOFs. On the basis of this strategy, we have constructed a library of meso-MOFs with tunable large pore sizes, controllable mesophases, various morphologies and multivariate components.