MOF synthesis

Due to its easy accessibility and photochemical as weU as thermal stability MOF-5 has been the typical study case for nanoparticle MOF synthesis and characterization. However, a few studies of other frameworks are known as well and are summarized in the following. 

In addition to the high degree of control over framework structure that can be achieved prior to and during MOF synthesis, considerable control can be exercised following framework assembly by exploiting the porosity of MOFs. Developments here have seen the emergence of a range of... 

MOF synthesis was originally accomplished by diffusion where the inorganic metals were diffused into solutions containing the organic backbones of the framewoik. However, diffusion was a very slow process that suffered from low yields. Hydrothermal synthesis is a common experimental technique that takes advantage of increased solubility of organic linkers at high temperatures and pressures. This... 

Fig. 8 Representative in situ organic reactions occurred during MOF synthesis...

Currently, mesoMOFs are mainly synthesized by solvothermal method. Microwave-assisted strategy has also been reported for the fast synthesis of mesoMOFs. Although this approach is not often used, it provides an opportunity for high speed MOFs synthesis with possible size and morphology control. In addition, three different strategies have been reported for the design of mesoMOFs (i) synthesis of mesoMOFs by extended ligands and bulky SBUs (ii) template-directed synthesis hierarchical mesoMOFs and (iii) template-free synthesis hierarchical mesoMOFs. 

Figure 3 Representative examples of anion-induced partial fluorination in MOFs achieved via -F ions by the addition of hydrofluoric add during MOF synthesis, (a) MIL-101 (Cr), (b) MIL-100 (Cr), and (c) MIL-71 (V ) (Hydrogen atoms and solvent molecules are omitted for clarity.)...

Metal ions with low toxicity that are poorly absorbed by the body, such as iron, magnesium, calcium, and zinc, are attractive candidates. Of these, iron and zinc have been extensively apphed in MOF synthesis, perhaps owing to the kinetic labihty of certain oxidation states and their affinity for carboxyfate donors. Other metafs are also suitable, depending on their toxicity in comparison to necessary dosage, but the toxicity of the MOF itself will originate from its metaboHtes, and so careful scrutiny of the speciation and breakdown of the MOF in the hmnan body is obviously required. 

Subsequently, Rosi et al. exploited the potential of adenine in MOF synthesis by preparing the so-called bio-MOF series, which have proven to exhibit some very exciting properties. Subjecting cobalt acetate and adenine to typical solvothermal conditions results in a MOF with the composition [Co2(ad)2(OAc)2]-2DMF-0.5H2O... 

The described mechanochemical methodologies have obvious advantages over solvothermal approaches used for porous MOF synthesis in terms of time (minutes vs days), temperature (near room-temperature vs 100-150 °C), and reactant choice (metal oxides vs soluble salts). Further advantages are the absence of bulk solvent and a wide choice of catalytic liquid phases, including ethanol, which is one of the more preferred solvents from a Green Chemistry perspective. The only waste product of the oxide-based reaction is water. The functional nature of porous MOFs obtained mechanochemically was recently investigated by Yuan and coworkers, who found that the Brunauer-Emmett-Teller (BET) surface area of the exemplary MOF HKUST-1 obtained by neat grinding of copper(II) acetate monohydrate with trimesic acid was comparable to that of samples obtained by conventional... 

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