Postsynthetic modification of MOFs

Furthermore, the postsynthetic modification of MOFs, either at the organic linkers or at the inorganic clusters [77, 136-139], is the best tool to open new possibilities to design efficient confined catalytic systems having defined single active site and fiexibility to accommodate substrates in a specific orientation in one word, the fine tuning of MOFs allows enzyme mimicking. 

A similar strategy of using photoactivation to cleave what may be viewed as protecting groups can similarly be used in the postsynthetic modification of MOFs. Cohen et al. demonstrated the use of a catechol-bearing terephthalic acid ligand, 2-((2-nitrobenzyl)oxy)terephthalic acid, into a MOF through the protection of the catechol moiety with nitrobenzyl... 

Electrochemical approaches to the synthesis and postsynthetic modification of MOFs should also be mentioned here, for instance, the synthesis of Zn-EZIF [41] or HKUST-1 [41]. 

In this regard, Decoste et proposed an alternative method for postsynthetic modification of Cu-BTC by a PECVD of perfluorohexane. The presynthesized and solvent-removed Cu-BTC crystals were converted to Cu-BTC plasma by using a PECVD method with a perfluorohexane precursor in a plasma reactor. The presence of CE3 groups on the surface of the pores also adds to the hydrophobicity of the material, which actually causes the material to float in liquid water avoiding the entry of these molecules to destruct the whole MOF framework. The treatment of Cu-BTC with plasma perfluorohexane enhances not only the stability of Cu-BTC against degradation by water but also the ammonia adsorption capacities (Figure 6). 

With a quest to MOF-catalyzed heterogeneous asymmetric catalysis via postsynthetic modification of porous backbone with Ti(OiPr)4, Wenbin Lin and coworkers experienced a novel SC-SC cross-linking... 

There are several basic approaches to the design of heterogeneous catalysts based on MOFs the use of MOFs as classical supports for an active metal, the immobilization of a catalytically active site in the framework per se (in the inorganic node or in the organic linker), host-guest interaction, postsynthetic modification of the framework, and so forth. These approaches will be discussed later in more detail. 

Despite the relatively large number of MOFs in current literature with accessible voids stable against guest exchange, the idea of being able to fine-tune an existing structure through postsynthetic modification or by incorporation of... 

Fig. 16 Functionalization of iron-carboxylate MOF with an optical imaging contrast agent (BODIPY) and a prodrug of cisplatin (ESCP) through postsynthetic modifications. Reprinted with the permission from [87]. Copyright 2009, American Chemical Society...

AAS = atomic absorption spectroscopy ATOF-MS = aerosol time-of-flight mass spectrometry 2,6-ndc = 2,6-naphthalenedicarboxylate bdc = 1,4-benzenedicar-boxylate bpdc = 1,3,5-benzenetricarboxylate bpydc = 2,2 -bipyridine-5,5 -dicarboxylate btb = 4,4, 4"-benzene-1,3,5-triylbenzoate btc = 1,3,5-benzenetricarboxylate 3D = three-dimensional dabco = l,4-diaza[2.2.2]bicyclo-octane EDX = energy-dispersive X-ray spectroscopy EXAFS = extended X-ray fine structure Fc = ferrocenyl ICP-AES = inductively coupled plasma atomic emission spectroscopy MOF = metal-organic framework PSD = postsynthetic deprotection PSM = Postsynthetic modification PXRD = Powder X-ray diffraction 1,4-ndc = 1,4-naphthalenedicarboxylate SALE = solvent-assisted linker exchange SBU = secondary building unit ... 

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