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Clip‐off Chemistry is a synthetic strategy that our group previously developed to obtain new molecules and materials through selective cleavage of bonds. Herein, we report recent work to expand Clip‐off Chemistry by introducing into it a retrosynthetic analysis step that, based on virtual extension of the products through cleavable bonds, enables one to define the required precursor materials. As proof‐of‐concept, we have validated our new approach by synthesising and characterising four aldehyde‐functionalised Rh(II)‐based complexes: a homoleptic cluster; a cis‐disubstituted paddlewheel cluster; a macrocycle; and a crown. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) based on high-connected nets are generally very attractive due to their combined robustness and porosity. Here, we describe the synthesis of BCN-348, a new high-connected Zr-MOF built from an 8-connected (8-c) cubic Zr-oxocluster and an 8-c organic linker. BCN-348 contains a minimal edge-transitive 3,4,8-c eps net, and combines mesoporosity with thermal and hydrolytic stability. Encouraging results from preliminary studies on its use as a catalyst for hydrolysis of a nerve-agent simulant suggest its potential as an agent for detoxification of chemical weapons and other pernicious compounds. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) possess high CO2 adsorption properties and are considered to be a promising candidate for the electrochemical carbon dioxide reduction reaction (eCO2RR). However, their insufficient selectivity and current density constrain their further exploration in the eCO2RR. In this work, by introducing a very small proportion of 2,5-dihydroxyterephthalic acid (DOBDC) into ZIF-8, a surface modified ZIF-8-5% catalyst was synthesized by a post-modification method, exhibiting enhanced selectivity (from 56% to 79%) and current density (from −4 mA cm−2 to −10 mA m−2) compared to ZIF-8. Density functional theory (DFT) calculations further demonstrate that the boosted eCO2RR performance on ZIF-8-5% could be attributed to the improved formation of the *COOH intermediate stemming from successful DOBDC surface modification. This work opens a new path for improving the catalytic properties of MOFs via their surface modification. [ABSTRACT FROM AUTHOR]

Self-assembly of colloidal particles into ordered superstructures enables the development of novel advanced materials for diverse applications such as photonics, electronics, sensing, energy conversion, energy storage, diagnosis, drug or gene delivery, and catalysis. Recently, polyhedral metal–organic framework (MOF) particles have been proposed as promising colloidal particles to form ordered superstructures, based on their colloidal stability, size-tunability, rich polyhedral shapes, porosity and multifunctionality. In this review, we present a comprehensive overview of strategies for the self-assembly of colloidal MOF particles into ordered superstructures of different dimensionalities, highlighting some of their properties and applications, and sharing thoughts on the self-assembly of MOF particles. [ABSTRACT FROM AUTHOR]

Increasing the chemical complexity of metal–organic cages (MOCs) or polyhedra (MOPs) demands control over the simultaneous organization of diverse organic linkers and metal ions into discrete caged structures. Herein, we show that a pre-assembled complex of the archetypical cuboctahedral MOP can be used as a template to replicate such caged structure, one having a "triblock Janus-type" configuration that is both heterometallic and heteroleptic. [ABSTRACT FROM AUTHOR]

We have synthesised and characterised the two possible isomers of heteroleptic trigonal antiprismatic M12L6L′6 MOPs by screening reactions of rhodium acetate with different pairs of complementary dicarboxylate linkers. The resulting 12 new MOPs (eight of isomer A + four of isomer B) are microporous in the solid state, exhibiting Brunauer–Emmett–Teller (BET) surface areas as high as 770 m2 g−1. [ABSTRACT FROM AUTHOR]

Multidrug‐resistant bacteria have become a global health problem for which new prophylactic strategies are now needed, including surface‐coatings for hospital spaces and medical equipment. This work reports the preparation and functional validation of a metal‐organic framework (MOF) based composite for the triggered controlled release of iodine, an antimicrobial element that does not generate resistance. It comprises beads of the iodophilic MOF UiO‐66 containing encapsulated gold nanorods (AuNRs) coated with a silica shell. Irradiation of the AuNRs with near‐infrared light (NIR) provokes a photothermal effect and the resultant heat actively liberates the iodine. After validating the performance of this composite, it is integrated into a polymer for the development of antibacterial films. This work assesses the adsorption of iodine into these composite films, as well as its passive long‐term release and active light‐triggered. Finally, this work validates the antibacterial activity of the composite films in vitro against gram‐positive and gram‐negative bacteria. The findings will surely inform the development of new prophylactic treatments. [ABSTRACT FROM AUTHOR]

Supraparticles are spherical colloidal crystals prepared by confined self‐assembly processes. A particularly appealing property of these microscale structures is the structural color arising from interference of light with their building blocks. Here, we assemble supraparticles with high structural order that exhibit coloration from uniform, polyhedral metal–organic framework (MOF) particles. We analyse the structural coloration as a function of the size of these anisotropic building blocks and their internal structure. We attribute the angle‐dependent coloration of the MOF supraparticles to the presence of ordered, onion‐like layers at the outermost regions. Surprisingly, even though different shapes of the MOF particles have different propensities to form these onion layers, all supraparticle dispersions show well‐visible macroscopic coloration, indicating that local ordering is sufficient to generate interference effects. [ABSTRACT FROM AUTHOR]

Bond breaking is an essential process in chemical transformations and the ability of researchers to strategically dictate which bonds in a given system will be broken translates to greater synthetic control. Here, we report extending the concept of selective bond breaking to reticular materials in a new synthetic approach that we call Clip‐off Chemistry. We show that bond‐breaking in these structures can be controlled at the molecular level; is periodic, quantitative, and selective; is effective in reactions performed in either solid or liquid phases; and can occur in a single‐crystal‐to‐single‐crystal fashion involving the entire bulk precursor sample. We validate Clip‐off Chemistry by synthesizing two topologically distinct 3D metal‐organic frameworks (MOFs) from two reported 3D MOFs, and a metal‐organic macrocycle from metal‐organic polyhedra (MOP). Clip‐off Chemistry opens the door to the programmed disassembly of reticular materials and thus to the design and synthesis of new molecules and materials. [ABSTRACT FROM AUTHOR]

The use of covalent organic frameworks (COFs) in practical applications demands shaping them into macroscopic objects, which remains challenging. Herein, we report a simple three‐step method to produce COF aerogels, based on sol‐gel transition, solvent‐exchange, and supercritical CO2 drying, in which 2D imine‐based COF sheets link together to form hierarchical porous structures. The resultant COF aerogel monoliths have extremely low densities (ca. 0.02 g cm−3), high porosity (total porosity values of ca. 99 %), and mechanically behave as elastic materials under a moderate strain (<25–35 %) but become plastic under greater strain. Moreover, these COF aerogels maintain the micro‐ and meso‐porosity of their constituent COFs, and show excellent absorption capacity (e.g. toluene uptake: 32 g g−1), with high removal efficiency (ca. 99 %). The same three‐step method can be used to create functional composites of these COF aerogels with nanomaterials. [ABSTRACT FROM AUTHOR]

Use of preformed metal‐organic polyhedra (MOPs) as supermolecular building blocks (SBBs) for the synthesis of metal‐organic frameworks (MOFs) remains underexplored due to lack of robust functionalized MOPs. Herein we report the use of polycarboxylate cuboctahedral RhII‐MOPs for constructing highly‐connected MOFs. Cuboctahedral MOPs were functionalized with carboxylic acid groups on their 12 vertices or 24 edges through coordinative or covalent post‐synthetic routes, respectively. We then used each isolated polycarboxylate RhII‐MOP as 12‐c cuboctahedral or 24‐c rhombicuboctahedral SBBs that, upon linkage with metallic secondary building units (SBUs), afford bimetallic highly‐connected MOFs. The assembly of a pre‐synthesized 12‐c SBB with a 4‐c paddle‐wheel SBU, and a 24‐c SBB with a 3‐c triangular CuII SBU gave rise to bimetallic MOFs having ftw (4,12)‐c or rht (3,24)‐c topologies, respectively. [ABSTRACT FROM AUTHOR]

The structural deterioration of archetypical, well‐faceted metal–organic frameworks (MOFs) has been evaluated upon exposure to an acidic environment (H2S). Experimental results show that the structural damage highly depends on the nature of the hybrid network (e.g., softness of the metal ions, hydrophilic properties, among others) and the crystallographic orientation of the exposed facets. Microscopy images show that HKUST‐1 with well‐defined octahedral (111) facets is completely deteriorated, ZIF‐8 with preferentially exposed (110) facets exhibits a large external deterioration with the development of holes or cavities in the mesoporous range, whereas UiO‐66‐NH2 with (111) exposed facets, and PCN‐250 with (100) facets does not reflect any sign of surface damage. Despite the selectivity in the external deterioration, X‐ray diffraction and gas adsorption measurements confirm that indeed all MOFs suffer an important internal deterioration, these effects being more severe for MOFs based on softer cations (e.g., Cu‐based HKUST‐1 and Fe‐based PCN‐250). These structural changes have inevitable important effects in the final adsorption performance for CO2 and CH4 at low and high pressures. [ABSTRACT FROM AUTHOR]

Herein we report the design, synthesis, structural characterisation and functional testing of a series of Cu(II) coordination polymers containing flexible 4,4′-dithiodibenzoate ligand (4,4′-DTBA), with or without auxiliary N-donor ligands. Reaction of Cu(II) with 4,4′-DTBA yielded a 1D coordination polymer (1) based on Cu(II) paddlewheel units connected by 4,4′-DTBA, to form cyclic loop chains with intramolecular voids that exhibit reversible structural transformations upon subsequent solvent exchange in methanol to afford a new, crystalline, permanently-porous structure (1′). However, when the same reaction was run with pyridine, it formed a porous 2D coordination polymer (2). We have attributed the difference in dimensionality seen in the two products to the coordination of pyridine on the axial site of the Cu(II) paddle-wheel, which forces flexible 4,4′-DTBA to adopt a different conformation. Reactions in the presence of 4,4′-bipyridine (4,4′-bpy) afforded two new, flexible, 2D coordination polymers (3 & 4). Lower concentrations of 4,4′-bpy afforded a structure (3) built from 1D chains analogous to those in 1 and connected through 4,4′-bpy linkers coordinated to the axial positions. Interestingly, 3 showed reversible structural transformations triggered by either solvent exchange or thermal treatment, each of which yielded a new crystalline and permanently porous phase (3′). Finally, use of higher concentrations of 4,4′-bpy led to a coordination polymer (4) based on a distorted CuO3N2 trigonal bipyramid, rather than on the Cu(II) paddlewheel. The connection of these motifs by 4,4′-DTBA resulted in a zig-zag 1D chain connected through 4,4′-bpy ligands to form a porous 2D network. Interestingly, 4 also underwent reversible thermal transformation to yield a microporous coordination polymer (4′). [ABSTRACT FROM AUTHOR]

Dynamic covalent bonds have been advantageously used to direct the synthesis of crystalline porous covalent organic frameworks (COFs). Unlike the standard synthetic protocols that involve harsh conditions, this work provides a high-yield "one-pot" green synthesis of imine-based COFs in water. Additionally, this aqueous synthesis can be performed under microwave conditions, considerably reducing the reaction time. [ABSTRACT FROM AUTHOR]

The production of metal–organic frameworks (MOFs) in the form of colloids has brought a paradigm shift in the design of new functional porous materials. Along with their intrinsic interest as porous solids, and contrary to their bulk powder counterparts, colloidal MOF particles can additionally be dispersed, shaped, functionalized, transformed and assembled in a controlled manner, conferring them further properties and applications. In this regard, zeolitic imidazolate framework-8 (ZIF-8) has become a pioneering MOF constituent of colloidal science. Today, the understanding of the role of synthetic parameters, learned after one decade of research, enables the production of monodisperse colloidal ZIF-8 particles with tunable dimensions and morphologies, offering the opportunity to develop new functional materials and composites with novel and promising functionalities. This tutorial review provides a useful guide to prepare ZIF-8 in its colloidal form, covering the published studies on the synthesis of homogeneous ZIF-8 particles with controlled size and shape. In addition, we present the most relevant advances in the development of colloidal ZIF-8 hybrid single-particles, reflecting the great potential and rapid development of this interdisciplinary research field. Finally, we highlight how formulation of ZIF-8 as colloids has led to the emergence of novel physicochemical phenomena that are useful for practical applications. This review aims at promoting the development of MOFs as colloids, taking ZIF-8 as a pioneering and successful case that clearly shows the benefits of bridging MOF chemistry and colloidal science. [ABSTRACT FROM AUTHOR]

Long chiral metal-organic nanofibers are grown by using conventional coordination chemistry and biologically derived components in a diffusion controlled growth procedure.

The new hexaferrocene complex, [[Fe.sub.3.sup.III.III.III]O[(FeCOO).sub.6][(DMF).sub.3]].Cl[O.sub.4] (DMF = N,N-dimethylformamide), is synthesized and characterized by X-ray diffraction. The cyclic voltammogram of this complex has confirmed its redox activity associated with the presence of ferrocene units, with very small or negligible electronic interactions between them.

The qualitative and quantitative insights into the exchange interaction involving 4d or 5d metal ions in cyano-bridged complexes are reported. Both the experimental and the calculated behaviors have revealed a noticeable difference between the Mo and the W derivatives that are correlated to the spin densities transferred by these metal ions onto the bridging cyano ligands.

A well-established strategy to synthesize heterogeneous, metal-organic framework (MOF) catalysts that exhibit nanoconfinement effects, and specific pores with highly-localized catalytic sites, is to use organic linkers containing organocatalytic centers. Here, we report that by combining this linker approach with reticular chemistry, and exploiting three-dimensioanl (3D) MOF-structural data from the Cambridge Structural Database, we have designed four heterogeneous MOF-based catalysts for standard organic transformations. These programmable MOFs are isoreticular versions of pcu IRMOF-16, fcu UiO-68 and pillared-pcu SNU-8X, the three most common topologies of MOFs built from the organic linker p,p'-terphenyldicarboxylic acid (tpdc). To synthesize the four squaramide-based MOFs, we designed and synthesized a linker, 4,4'-((3,4‐dioxocyclobut‐1‐ene‐1,2‐diyl)bis(azanedyil))dibenzoic acid (Sq_tpdc), which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers. Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena. Therefore, the four MOFs share the same organocatalytic squaramide moiety, but confine it within distinct pore environments. We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations: a Friedel-Crafts alkylation and an epoxide ring-opening. Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences. [ABSTRACT FROM AUTHOR]

Supramolecular isomerism of metal–organic frameworks (MOFs) is known for several MOF structures, having direct implications on the properties of these materials. Although the synthesis of MOF isomers is mainly serendipitous in nature, achieving controlled formation of a target framework is highly relevant for practical applications. This work discusses the influence of additives and synthesis conditions on the formation of porous isomers containing Zn2+ as nodes and 2,5-dihydroxy-1,4-benzenedicarboxylate (dobdc4–) as a linker. Using solvent mixtures containing strongly coordinated molecules, e.g. N,N′-dimethylformamide (DMF) and N-methylpyrrolidone (NMP), facilitates the formation of porous structures of type [Zn2(dobdc)(S)x]·yS (S = DMF, NMP) which are built from dinuclear Zn2(O)2(CO2)3 secondary building units (SBUs) consisting of two different edge-sharing polyhedra with the Zn2+ ions in a unsaturated coordinative environment. In the presence of water, the Zn2+ dimers are converted to one-dimensional infinite Zn2+ chains, in which the number of Zn2+-linker bonds increases, therefore giving a hydrolytically more stable coordination environment. The full characterization of the isomers as well as their conversion to the most stable isomer is presented. [ABSTRACT FROM AUTHOR]

Herein, we describe a new class of porous composites comprising metal–organic framework (MOF) crystals confined in single spherical matrices made of packed covalent‐organic framework (COF) nanocrystals. These MOF@COF composites are synthesized through a two‐step method of spray‐drying and subsequent amorphous (imine‐based polymer)‐to‐crystalline (imine‐based COF) transformation. This transformation around the MOF crystals generates micro‐ and mesopores at the MOF/COF interface that provide far superior porosity compared to that of the constituent MOF and COF components added together. We report that water sorption in these new pores occurs within the same pressure window as in the COF pores. Our new MOF@COF composites, with their additional pores at the MOF/COF interface, should have implications for the development of new composites. [ABSTRACT FROM AUTHOR]

A novel naphthalene-based 5·(BArF)8 capsule allows for the size-selective inclusion of C60 from fullerene mixtures. Its size selectivity towards C60 has been rationalized by its dynamic adaptability in solution that has been investigated by molecular dynamics. Additionally, 5·(BArF)8 encapsulates C60-derivatives such as C60-PCBM and N-methylpyrrolidine-C60. The latter can be separated from C60 since 5·(BArF)8 displays distinct affinity for them. [ABSTRACT FROM AUTHOR]