Molecular decoding using luminescence from an entangled porous framework

Chemosensors detect a single target molecule from among several molecules, but cannot differentiate targets from one another. In this study, we report a molecular decoding strategy in which a single host domain accommodates a class of molecules and distinguishes between them with a corresponding readout. We synthesized the decoding host by embedding naphthalenediimide into the scaffold of an entangled porous framework that exhibited structural dynamics due to the dislocation of two chemically non-interconnected frameworks. An intense turn-on emission was observed on incorporation of a class of aromatic compounds, and the resulting luminescent colour was dependent on the chemical substituent of the aromatic guest. This unprecedented chemoresponsive, multicolour luminescence originates from an enhanced naphthalenediimide–aromatic guest interaction because of the induced-fit structural transformation of the entangled framework. We demonstrate that the cooperative structural transition in mesoscopic crystal domains results in a nonlinear sensor response to the guest concentration

On the Electronic and Optical Properties of Metal-Organic Frameworks: Case Study of MIL-125 and MIL-125-NH2

The photoactive MIL-125 and MIL-125-NH$_{2}$ Metal-Organic Frameworks (MOFs), despite a very similar crystalline structure, exhibit different optically behaviour. Luminescence in MIL-125 decays in about 1 ns while for its amino counterpart the lifetime of the charge-carriers is at least one order of magnitude larger. The origin of this difference is the key element for understanding the photocatalytic behaviour of MIL-125-NH2 when associated with active nanoparticles, behaviour that is completely absent in MIL-125. By performing advancedab-initio electronic structure calculations, we find that charge-carriers interact differently in the two MOFs with subsequent effects on the luminescence lifetimes and their catalytic performances. To confirm the predictions of our model we synthesized a novel material in the MIL-125 family, MIL-125-NH2-[10%](OH)2, and confirm that our theory correctly predicts a faster decay compared to MIL-125-NH2.</div

Lanthanide-based near-infrared emitting metal-organic frameworks with tunable excitation wavelengths and high quantum yields

The introduction of –NH2 group in SION-100 allows the visible light absorption, and both SION-100 and SION-100-NH2 luminesce NIR light with long lifetimes and high quantum yields.</p

An Adaptable Peptide-Based Porous Material

Porous materials find widespread application in storage, separation, and catalytic technologies. We report a crystalline porous solid with adaptable porosity, in which a simple dipeptide linker is arranged in a regular array by coordination to metal centers. Experiments reinforced by molecular dynamics simulations showed that low-energy torsions and displacements of the peptides enabled the available pore volume to evolve smoothly from zero as the guest loading increased. The observed cooperative feedback in sorption isotherms resembled the response of proteins undergoing conformational selection, suggesting an energy landscape similar to that required for protein folding. The flexible peptide linker was shown to play the pivotal role in changing the pore conformation

Data-driven design of metal–organic frameworks for wet flue gas CO<inf>2</inf> capture

Limiting the increase of CO2 in the atmosphere is one of the largest challenges of our generation1. Because carbon capture and storage is one of the few viable technologies that can mitigate current CO2 emissions2, much effort is focused on developing solid adsorbents that can efficiently capture CO2 from flue gases emitted from anthropogenic sources3. One class of materials that has attracted considerable interest in this context is metal–organic frameworks (MOFs), in which the careful combination of organic ligands with metal-ion nodes can, in principle, give rise to innumerable structurally and chemically distinct nanoporous MOFs. However, many MOFs that are optimized for the separation of CO2 from nitrogen4–7 do not perform well when using realistic flue gas that contains water, because water competes with CO2 for the same adsorption sites and thereby causes the materials to lose their selectivity. Although flue gases can be dried, this renders the capture process prohibitively expensive8,9. Here we show that data mining of a computational screening library of over 300,000 MOFs can identify different classes of strong CO2-binding sites—which we term ‘adsorbaphores’—that endow MOFs with CO2/N2 selectivity that persists in wet flue gases. We subsequently synthesized two water-stable MOFs containing the most hydrophobic adsorbaphore, and found that their carbon-capture performance is not affected by water and outperforms that of some commercial materials. Testing the performance of these MOFs in an industrial setting and consideration of the full capture process—including the targeted CO2 sink, such as geological storage or serving as a carbon source for the chemical industry—will be necessary to identify the optimal separation material