Metal–organic frameworks (MOFs) have rapidly grown into a major area of chemical research over the last two decades. MOFs represent the development of covalent chemistry “beyond the molecule” and ...into extended structures. MOFs also present an unprecedented scaffold for performing heterogeneous organic transformations in the solid state, allowing for deliberate and precise preparation of new materials. The development of these transformations has given rise to the “postsynthetic renaissance”, a suite of methods by which these materials can be transformed in a single-crystal-to-single-crystal manner. Postsynthetic modification, postsynthetic deprotection, postsynthetic exchange, postsynthetic insertion, and postsynthetic polymerization have exploited the unique features of both the organic and inorganic components of MOFs to create crystalline, porous solids of unique complexity and functionality.
Metal–organic frameworks (MOFs) are a class of porous materials with immense chemical tunability derived from their organic and inorganic building blocks. Presynthetic approaches have been used to ...construct tailor-made MOFs, but with a rather restricted functional group scope limited by the typical MOF solvothermal synthesis conditions. Postsynthetic modification (PSM) of MOFs has matured into an alternative strategy to broaden the functional group scope of MOFs. PSM has many incarnations, but two main avenues include (1) covalent PSM, in which the organic linkers of the MOF are modified with a reagent resulting in new functional groups, and (2) coordinative PSM, where organic molecules containing metal ligating groups are introduced onto the inorganic secondary building units (SBUs) of the MOF. These methods have evolved from simple efforts to modifying MOFs to demonstrate proof-of-concept, to becoming key synthetic tools for advancing MOFs for a range of emerging applications, including selective gas sorption, catalysis, and drug delivery. Moreover, both covalent and coordinative PSM have been used to create hierarchal MOFs, MOF-based porous liquids, and other unusual MOF materials. This Outlook highlights recent reports that have extended the scope of PSM in MOFs, some seminal reports that have contributed to the advancement of PSM in MOFs, and our view on future directions of the field.
The incorporation of 2,3-dimercaptoterephthalate (thiocatecholate, tcat) into a highly robust UiO-type metal–organic framework (MOF) has been achieved via postsynthetic exchange (PSE). The anionic, ...electron-donating thiocatecholato motif provides an excellent platform to obtain site-isolated and coordinatively unsaturated soft metal sites in a robust MOF architecture. Metalation of the thiocatechol group with palladium affords unprecedented Pd-mono(thiocatecholato) moieties within these MOFs. Importantly, Pd-metalated MOFs are efficient, heterogeneous, and recyclable catalysts for regioselective functionalization of sp2 C–H bond. This material is a rare example of chelation-assisted C–H functionalization performed by a MOF catalyst.
The modification of metal-organic frameworks (MOFs) in a postsynthetic scheme is discussed in this critical review. In this approach, the MOF is assembled and then modified with chemical reagents ...with preservation of the lattice structure. Recent findings show amide couplings, isocyanate condensations, 'click' chemistry, and other reactions are suitable for postsynthetic modification (PSM). In addition, a number of MOFs, from IRMOF-3 to ZIF-90, are amenable to PSM. The generality of PSM, in both scope of chemical reactions and range of suitable MOFs, clearly indicates that the approach is broadly applicable. Indeed, the rapid increase in reports on PSM demonstrates this methodology will play an increasingly important role in the development of MOFs for the foreseeable future (117 references).
Synthesis of CF3-containing compounds is of great interest because of their broad use in the pharmaceutical and agrochemical industries. Herein, selective 2,2,2-trifluoroethylation of styrenes was ...catalyzed by Zr(IV)-based MOFs bearing visible-light photocatalysts in the form of Ir(III) polypyridyl complexes. When compared to the homogeneous Ir(III) catalyst, the MOF-based catalyst suppressed the dimerization of benzyl radicals, thus enhancing the selectivity of the desired hydroxytrifluoroethyl compounds.
Metal-organic frameworks (MOFs) are an important class of hybrid inorganic-organic materials. In this tutorial review, a progress report on the postsynthetic modification (PSM) of MOFs is provided. ...PSM refers to the chemical modification of the MOF lattice in a heterogeneous fashion. This powerful synthetic approach has grown in popularity and resulted in a number of advances in the functionalization and application of MOFs. The use of PSM to develop MOFs with improved gas sorption, catalytic activity, bioactivity, and more robust physical properties is discussed. The results reported to date clearly show that PSM is an important approach for the development and advancement of these hybrid solids.
Metal-dependent enzymes (i.e., metalloenzymes) make up a large fraction of all enzymes and are critically important in a wide range of biological processes, including DNA modification, protein ...homeostasis, antibiotic resistance, and many others. Consequently, metalloenzymes represent a vast and largely untapped space for drug development. The discovery of effective therapeutics that target metalloenzymes lies squarely at the interface of bioinorganic and medicinal chemistry and requires expertise, methods, and strategies from both fields to mount an effective campaign. In this Account, our research program that brings together the principles and methods of bioinorganic and medicinal chemistry are described, in an effort to bridge the gap between these fields and address an important class of medicinal targets. Fragment-based drug discovery (FBDD) is an important drug discovery approach that is particularly well suited for metalloenzyme inhibitor development. FBDD uses relatively small but diverse chemical structures that allow for the assembly of privileged molecular collections that focus on a specific feature of the target enzyme. For metalloenzyme inhibition, the specific feature is rather obvious, namely, a metal-dependent active site. Surprisingly, prior to our work, the exploration of diverse molecular fragments for binding the metal active sites of metalloenzymes was largely unexplored. By assembling a modest library of metal-binding pharmacophores (MBPs), we have been able to find lead hits for many metalloenzymes and, from these hits, develop inhibitors that act via novel mechanisms of action. A specific case study on the use of this strategy to identify a first-in-class inhibitor of zinc-dependent Rpn11 (a component of the proteasome) is highlighted. The application of FBDD for the development of metalloenzyme inhibitors has raised several other compelling questions, such as how the metalloenzyme active site influences the coordination chemistry of bound fragments, how one can identify the best fragments for a given metalloenzyme, and many others. Among the most significant, and concerning, questions for metalloenzyme inhibition are those that reside around issues of specificity and whether metalloenzyme inhibitors can be as selective and specific as other small molecule inhibitors (i.e., compounds that inhibit enzymes that do not utilize a metal at their active site). This also leads to the question of whether metalloenzyme inhibitors might interfere more broadly with the metallome. Efforts to address these and related questions are discussed, with the expectation that our findings will illuminate some of these topics, alleviate some of these concerns, and encourage greater interest in this important, undervalued class of drug targets.
The fields of coordination polymers (CPs) and supramolecular metallopolymers (SMPs) have been extensively studied for decades. Spectacular recent advances in both fields have created new compounds ...that lie at the interface between these two classes of organic‐inorganic hybrid materials. At this interface, materials based on molecular weaving, supramolecular clusters, and metal‐organic framework‐polymer hybrids have emerged. This minireview provides a perspective on the intellectual emergence and connection between different supramolecular constructs and the state of the art with respect to this new materials interface.
At the interface between coordination polymers and supramolecular metallopolymers, materials based on molecular weaving, supramolecular clusters, and metal‐organic framework‐polymer hybrids have emerged. This Minireview provides an intellectual roadmap from the development of supramolecular metallopolymers to new materials that blur the lines between metallopolymers and coordination polymers.
A photocatalytic Ru complex was incorporated into a Zr(iv)-based metal-organic framework (MOF) via postsynthetic methods. The resulting UiO-67-Ru(bpy)3 shows efficient and recyclable catalytic ...activity for the aerobic oxidation of arylboronic acids under near-UV and visible light irradiation.
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