Metal‐Organic Framework Nanocrystals

Metal‐organic frameworks (MOFs) comprise a broad class of crystalline materials defined as porous networks consisting of metal ions or clusters interconnected through polytopic organic linkers. Due to their intriguing structural and topological characteristics which usually offer high surface areas and tunable pore size, MOFs are excellent candidates for a great variety of applications, such as gas adsorption and separation, catalysis, magnetism, photoluminescence and many others. Although attractive, traditional bulk crystalline MOF materials do not always fulfill the specific needs for some applications, such as smart membranes, thin films devices, and drug delivery. Moreover, nanocrystals display properties that differ from the bulk material due to the high surface‐to‐volume ratio and quantum size effects. Thus, MOF nanocrystals will possibly present new and exciting properties or at least enhance the already known ones. With this view, it is necessary to develop efficient strategies towards the synthesis of MOF nanocrystals. This review provides general concepts of MOF nanocrystals and a critical summary of synthetic approaches with the focus on recent progress in the fabrication of MOF nanocrystals. Nanoscale Metal‐Organic Framework (MOF) crystals possess unique features due to their high surface‐to‐volume ratio and quantum size effects. However, the precise control over the size and shape of MOF nanocrystals remains a challenge. Here, synthetic approaches in the fabrication of MOF nanocrystals are critically discussed, what may be useful to inspire further investigations into the fabrication of nanoscale MOF crystals.