19F NMR Probes: Molecular Logic Material Implications for the Anion Discrimination and Chemodosimetric Approach for Selective Detection of H2O2.

Detection and discrimination of similar solvation energies of bioanalytes are vital in medical and practical applications. Currently, various advanced techniques are equipped to recognize these crucial bioanalytes. Each strategy has its own benefits and limitations. One-dimensional response, lack of discrimination power for anions, and reactive oxygen species (ROS) generally limit the utilized fluorescent probe. Therefore, a cutting-edge, refined method is expected to conquer these limitations. The use of 19F NMR spectroscopy for detecting and discriminating essential analytes in practical applications is an emerging technique. As an alternative strategy, we report two fluorinated boronic acid-appended pyridinium salts 5-F-o-BBBpy (1) and 5-CF3-o-BBBpy (2). Probe (1) acts as a chemosensor for identifying and discriminating inorganic anions with similar solvation energies with strong bidirectional 19F shifts in the lower ppm range. Probe (2) turns as a chemo dosimeter for the selective detection and precise quantification of hydrogen peroxide (H2O2) among other competing ROS. To demonstrate real-life applicability, we successfully quantified H2O2 via probe (2) in different pharmaceutical, dental, and cosmetic samples. We found that tuning the -F/-CF3 moiety to the arene boronic acid enables the π-conjugation, a crucial prerequisite for the discrimination of anions and H2O2. Characteristic 19F NMR fingerprints in the presence of anions revealed a complementary implication (IMP)/not implication (NIMP) logic function. Finally, the 16 distinct binary Boolean operations on two logic values are defined for "functional completeness" using the special property of the IMP gate. Boolean logic's ability to handle information by utilizing characteristic 19F NMR fingerprints has not been seen previously in a single chemical platform for detecting and differentiating such anions.

Quantifying CO-release from a photo-CORM using 19F NMR: An investigation into light-induced CO delivery.

Carbon monoxide (CO) is an innate signaling molecule that can regulate immune responses and interact with crucial elements of the circadian clock. Moreover, pharmacologically, CO has been substantiated for its therapeutic advantages in animal models of diverse pathological conditions. Given that an excessive level of CO can be toxic, it is imperative to quantify the necessary amount for therapeutic use accurately. However, estimating gaseous CO is notably challenging. Therefore, novel techniques are essential to quantify CO in therapeutic applications and overcome this obstacle precisely. The classical Myoglobin (Mb) assay technique has been extensively used to determine the amount of CO-release from CO-releasing molecules (CORMs) within therapeutic contexts. Nevertheless, specific challenges arise when applying the Mb assay to evaluate CORMs featuring innovative molecular architectures. Here, we report a fluorinated photo-CORM (CORM-FBS) for the photo-induced CO-release. We employed the 19F NMR spectroscopy approach to monitor the release of CO as well as quantitative evaluation of CO release. This new 19F NMR approach opens immense opportunities for researchers to develop reliable techniques for identifying molecular structures, quantitative studies of drug metabolism, and monitoring the reaction process.

TiO2 supported pallidum-bipyridyl complex as an efficient catalyst for Suzuki-Miyaura reaction in aqueous-ethanol.

Owing to their improved catalytic stability and ability to undergo repeated cycles, solid-supported catalysts show great potential for various catalytic reactions. In this study, we synthesized a catalyst comprising a palladium-2,2-bipyridine complex supported on TiO2 nanoparticles (TiO2@BDP-PdCl2) fully characterised and investigated its efficacy in Suzuki-Miyaura cross coupling reactions involving phenyl boronic acid with various aryl halides under mild reaction conditions. The 2,2'- bipyridine (bp) has shown excellent complexation properties for Pd (II) and it could be easily anchored onto functionalized TiO2 support by the bridging carboxylate ions. The composition and structure of the as-prepared catalyst was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Transmission Electron Microscope (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. The catalyst easily demonstrated separability, enhancing its practicality in catalytic processes. Subsequent utilization showed a consistent activity level, suggesting the stabilization of the aggregated catalyst species. This research sheds light on the importance of catalyst stability and maintenance during consecutive reaction cycles.

Lysosome targeted visible light-induced photo-CORM for simultaneous CO-release and singlet oxygen generation.

We report a specific lysosome targeted light-responsive CO-releasing molecule (Lyso-CORM). Lyso-CORM is very stable under dark conditions. CO and singlet oxygen (1O2) generation was effectively triggered under one photon and two photon excitation (800 nm) conditions. The cytotoxicity results demonstrated that Lyso-CORM showed good phototoxicity due to the synergistic effect of CO and 1O2 release, and its good biocompatibility, negligible dark toxicity and specific lysosome targeting make Lyso-CORM a potent candidate for phototherapeutic applications.

Upgrading gasoline to high octane numbers using a zeolite-like metal-organic framework molecular sieve with ana-topology.

Separation of paraffin isomers is of great importance in the refining industry because of their potential applications for energy efficiency, as reflected by their associated Research Octane Number (RON) values. Here, we report the synthesis of the first zeolite-like metal-organic framework (ZMOF) with ana topology that displays helicoidally/cylindrically-shaped channels with a pore-aperture size of ca. 3.8 × 6.2 Å. Markedly, such structural features offer potential for the selective separation of linear, and mono- and dibranched paraffins. Largely due to its tuned pore size and the presence of ions in the channels, ana-ZMOF possesses an excellent uniform charge density that allows the kinetic separation of n-pentane versus iso-pentane and n-butane vs. iso-butane, as well as the molecular exclusion of 2,2,4-trimethyl pentane.

The effect of pressure on the post-synthetic modification of a nanoporous metal-organic framework.

Here we report four post-synthetic modifications, including the first ever example of a high pressure-induced post-synthetic modification, of a porous copper-based metal-organic framework. Ligand exchange with a water ligand at the axial metal site occurs with methanol, acetonitrile, methylamine and ethylamine within a single-crystal and without the need to expose a free metal site prior to modification, resulting in significant changes in the pore size, shape and functionality. Pressure experiments carried out using isopropylalcohol and acetaldehyde, however, results in no ligand exchange. By using these solvents as hydrostatic media for high-pressure single-crystal X-ray diffraction experiments, we have investigated the effect of ligand exchange on the stability and compressibility of the framework and demonstrate that post-synthetic ligand exchange is very sensitive to both the molecular size and functionality of the exchanged ligand. We also demonstrate the ability to force hydrophilic molecules into hydrophobic pores using high pressures which results in a pressure-induced chemical decomposition of the Cu-framework.

Porous organic polymers with anchored aldehydes: a new platform for post-synthetic amine functionalization en route for enhanced CO2 adsorption properties.

A novel porous organic polymer has been synthesized using the molecular building block approach to deliberately encompass aldehyde functionalities amenable to post functionalization. The resultant porous framework allows a facile, one-step quantitative and post-synthetic functionalization by amines, permitting enhanced CO2 sorption properties.

High-resolution solid-state 13C NMR spectroscopy of the paramagnetic metal-organic frameworks, STAM-1 and HKUST-1.

Solid-state (13)C magic-angle spinning (MAS) NMR spectroscopy is used to investigate the structure of the Cu(II)-based metal-organic frameworks (MOFs), HKUST-1 and STAM-1, and the structural changes occurring within these MOFs upon activation (dehydration). NMR spectroscopy is an attractive technique for the investigation of these materials, owing to its high sensitivity to local structure, without any requirement for longer-range order. However, interactions between nuclei and unpaired electrons in paramagnetic systems (e.g., Cu(II)-based MOFs) pose a considerable challenge, not only for spectral acquisition, but also in the assignment and interpretation of the spectral resonances. Here, we exploit the rapid T(1) relaxation of these materials to obtain (13)C NMR spectra using a spin-echo pulse sequence at natural abundance levels, and employ frequency-stepped acquisition to ensure uniform excitation of resonances over a wide frequency range. We then utilise selective (13)C isotopic labelling of the organic linker molecules to enable an unambiguous assignment of NMR spectra of both MOFs for the first time. We show that the monomethylated linker can be recovered from STAM-1 intact, demonstrating not only the interesting use of this MOF as a protecting group, but also the ability (for both STAM-1 and HKUST-1) to recover isotopically-enriched linkers, thereby reducing significantly the overall cost of the approach.

Protecting group and switchable pore-discriminating adsorption properties of a hydrophilic-hydrophobic metal-organic framework.

Formed by linking metals or metal clusters through organic linkers, metal-organic frameworks are a class of solids with structural and chemical properties that mark them out as candidates for many emerging gas storage, separation, catalysis and biomedical applications. Important features of these materials include their high porosity and their flexibility in response to chemical or physical stimuli. Here, a copper-based metal-organic framework has been prepared in which the starting linker (benzene-1,3,5-tricarboxylic acid) undergoes selective monoesterification during synthesis to produce a solid with two different channel systems, lined by hydrophilic and hydrophobic surfaces, respectively. The material reacts differently to gases or vapours of dissimilar chemistry, some stimulating subtle framework flexibility or showing kinetic adsorption effects. Adsorption can be switched between the two channels by judicious choice of the conditions. The monoesterified linker is recoverable in quantitative yield, demonstrating possible uses of metal-organic frameworks in molecular synthetic chemistry as 'protecting groups' to accomplish selective transformations that are difficult using standard chemistry techniques.