The first bioinspired microporous metal–organic framework (MOF) synthesized using ellagic acid, a common natural antioxidant and polyphenol building unit, is presented. Bi 2 O(H 2 O) 2 (C 14 H 2 O 8 )· n H 2 O (SU-101) was inspired by bismuth phenolate metallodrugs, and could be synthesized entirely from nonhazardous or edible reagents under ambient aqueous conditions, enabling simple scale-up. Reagent-grade and affordable dietary supplement-grade ellagic acid was sourced from tree bark and pomegranate hulls, respectively. Biocompatibility and colloidal stability were confirmed by in vitro assays. The material exhibits remarkable chemical stability for a bioinspired MOF (pH = 2–14, hydrothermal conditions, heated organic solvents, biological media, SO 2 and H 2 S), attributed to the strongly chelating phenolates. A total H 2 S uptake of 15.95 mmol g –1 was recorded, representing one of the highest H 2 S capacities for a MOF, where polysulfides are formed inside the pores of the material. Phenolic phytochemicals remain largely unexplored as linkers for MOF synthesis, opening new avenues to design stable, eco-friendly, scalable, and low-cost MOFs for diverse applications, including drug delivery.

No abstract

A new porous titanium(IV) squarate metal–organic framework (MOF), denoted as IEF‐11, having a never reported titanium secondary building unit, is successfully synthesized and fully characterized. IEF‐11 not only exhibits a permanent porosity but also an outstanding chemical stability. Further, as a consequence of combining the photoactive Ti(IV) and the electroactive squarate, IEF‐11 presents relevant optoelectronic properties, applied here to the photocatalytic overall water splitting reaction. Remarkably, IEF‐11 as a photocatalyst is able to produce record H2 amounts for MOF‐based materials under simulated sunlight (up to 672 µmol gcatalyst in 22 h) without any activity loss during at least 10 d.

A molecular crystal of a 2-D hydrogen-bonded organic framework (HOF) undergoes an unusual structural transformation after solvent removal from the crystal pores during activation. The conformationally flexible host molecule, ABTPA , adapts its molecular conformation during activation to initiate a framework expansion. The microcrystalline activated phase was characterized by three-dimensional electron diffraction (3D ED), which revealed that ABTPA uses out-of-plane anthracene units as adaptive structural anchors. These units change orientation to generate an expanded, lower density framework material in the activated structure. The porous HOF, ABTPA-2 , has robust dynamic porosity (SA BET = 1183 m 2 g –1 ) and exhibits negative area thermal expansion. We use crystal structure prediction (CSP) to understand the underlying energetics behind the structural transformation and discuss the challenges facing CSP for such flexible molecules.

Designing polymeric materials for closed-loop material streams is the key to achieving a circular society. Here, a library of macrocyclic carbonates (MCs) was designed by a facile and direct one-pot, two-step synthesis approach without the use of a solvent at a 10 g scale. We demonstrate that anionic polymerization with tert-butoxide enables the ultrafast ring-opening polymerization (ROP) of MCs with high conversion (>97%) within seconds (3–10 s) at ambient temperature. The polymerization rate depends on the odd or even number of methylene groups between the carbonate linkages in the MCs, and not the overall ring size, yielding an “odd–even” effect. This polymerization rate is related to the difference in molecular conformation of the MCs, as determined by X-ray crystallography. The polymers (polypenta-, hexa-, heptamethylene carbonate) were subsequently regenerated back to their original MCs at a high selectivity (95–99 mol %) and good yields (70–85%), hence taking a step toward closing the loop on these long alkyl chain polycarbonates.

Catalysts for photochemical reactions underlie many foundations in our lives, from natural light harvesting to modern energy storage and conversion, including processes such as water photolysis by TiO2. Recently, metal–organic frameworks (MOFs) have attracted large interest within the chemical research community, as their structural variety and tunability yield advantages in designing photocatalysts to address energy and environmental challenges. Here, we report a series of novel multivariate metal–organic frameworks (MTV-MOFs), denoted as MTV-MIL-100. They are constructed by linking aromatic carboxylates and AB2OX3 bimetallic clusters, which have ordered atomic arrangements. Synthesized through a solvent-assisted approach, these ordered and multivariate metal clusters offer an opportunity to enhance and fine-tune the electronic structures of the crystalline materials. Moreover, mass transport is improved by taking advantage of the high porosity of the MOF structure. Combining these key advantages, MTV-MIL-100­(Ti,Co) exhibits a high photoactivity with a turnover frequency of 113.7 molH2 gcat. –1 min–1, a quantum efficiency of 4.25%, and a space time yield of 4.96 × 10–5 in the photocatalytic hydrolysis of ammonia borane. Bridging the fields of perovskites and MOFs, this work provides a novel platform for the design of highly active photocatalysts.

Electron transport through metal−organic frameworks by a hopping mechanism between discrete redox active sites is coupled to diffusionmigration of charge-balancing counter cations. Experimentally determined apparent diffusion coefficients, D e app , that characterize this form of charge transport thus contain contributions from both processes. While this is well established for MOFs, microscopic descriptions of this process are largely lacking. Herein, we systematically lay out different scenarios for cation-coupled electron transfer processes that are at the heart of charge diffusion through MOFs. Through systematic variations of solvents and electrolyte cations, it is shown that the D e app for charge migration through a PIZOF-type MOF, Zr(dcphOH-NDI) that is composed of redox-active naphthalenediimide (NDI) linkers, spans over 2 orders of magnitude. More importantly, however, the microscopic mechanisms for cation-coupled electron propagation are contingent on differing factors depending on the size of the cation and its propensity to engage in ion pairs with reduced linkers, either non-specifically or in defined structural arrangements. Based on computations and in agreement with experimental results, we show that ion pairing generally has an adverse effect on cation transport, thereby slowing down charge transport. In Zr(dcphOH-NDI), however, specific cation−linker interactions can open pathways for concerted cation-coupled electron transfer processes that can outcompete limitations from reduced cation flux.

The metallocene-based linker molecule 1,1′-ferrocenedicarboxylic acid (H2FcDC) was used to synthesize four different polymorphs of composition [In­(OH)­(FeC12H8O4)]. Using conventional solvent-based synthesis methods and varying the synthetic parameters such as metal source, reaction temperature, and solvent, two different MOFs and one 1D-coordination polymer denoted as CAU-43 (1), In-MIL-53-FcDC_a (2), and In-FcDC (3) were obtained. Furthermore, thermal treatment of CAU-43 (1) at 190 °C under vacuum yielded a new polymorph of 2, In-MIL-53-FcDC_b (4). Both MOFs 2 and 4 crystallize in a MIL-53 type structure, but in different space groups C2/m for 2 and P1̅ for 4. The structures of the four title compounds were determined by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), or a combination of three-dimensional electron diffraction measurements (3D ED) and PXRD. N2 sorption experiments of 1, 2, and 4 showed specific surface areas of 355 m2 g–1, 110 m2 g–1, and 140 m2 g–1, respectively. Furthermore, the electronic properties of the title compounds were characterized via Mössbauer and EPR spectroscopy. All Mössbauer spectra showed the characteristic doublet, proving the persistence of the ferrocene moiety. In the cases of 1, 3, and 4, appreciable impurities of ferrocenium ions could be detected by electron paramagnetic resonance spectroscopy. Cyclovoltammetric experiments were performed to demonstrate the accessible redox activity of the linker molecule of the title compounds. A redox process of FcDC2– with oxidation (between 0.86 and 0.97 V) and reduction wave (between 0.69 and 0.80 V) was observed.