Highly defective ultra-small M(IV)-MOF nanocrystals

A precise and concomitant control of both the size and defects in inorganic materials is of importance in many applications, particularly catalysis, as it often results in enhanced properties or emerging new features. So far, applying the strategy of modulation chemistry has been unable to afford high-quality functional Metal-Organic Frameworks (MOFs) nanocrystals with minimized size while exhibiting maximized defects. We report here a general sustainable strategy for the design of highly defective and ultra-small M(IV)-MOFs crystals (ca. 35% missing linker, 4-6 nm). Advanced characterizations have been performed to shed light on the main factors governing the crystallization mechanism and to identify the nature of the defects. The ultra-small Zr-MOFs showed excellent performance in peptide hydrolysis reaction, including high reactivity, selectivity, diffusion, stability, and show emerging tailorable reactivity and selectivity towards peptide bond formation simply by changing the reaction solvent. Therefore, these highly defective ultra-small tetravalent MOFs particles open new perspectives for the development of heterogeneous MOF catalysts with dual functions.