Exploring the Chiral Match-Mismatch Effect in the Chiral Discrimination of Nitriles.

This study tackles the challenge of enantiodifferentiation of nitrile compounds, which is typically difficult to resolve using nuclear magnetic resonance (NMR) due to the significant distance between the chiral center and the nitrogen atom involved in molecular interactions. We have developed novel chiral F-labeled probes, each featuring two chiral centers, to exploit the "match-mismatch" effect, thereby enhancing enantiodiscrimination. This strategy effectively differentiates chiral analytes with quaternary chiral carbon centers as well as those with similar substituents at the chiral center.

Bioinspired Ion Host with Buried and Consecutive Binding Sites for Controlled Ion Dislocation.

This study presents a bioinspired ion host featuring continuous binding sites arranged in a tunnel-like structure, closely resembling the selectivity filter of natural ion channels. Our investigation reveals that ions traverse these sites in a controlled, sequential manner due to the structural constraints, effectively mimicking the ion translocation process observed in natural channels. Unlike systems with open binding sites, our model facilitates sequential ion recognition state transitions, enabled by the deliberate design of the tunnel.

Enhancing Molecular-Level Biological Monitoring with a Smart Self-Assembling F-Labeled Probe.

Real-time monitoring of molecular transformations is crucial for advancements in biotechnology. In this study, we introduce a novel self-assembling F-labeled nuclear magnetic resonance (NMR) probe that disassembles upon interaction with various nucleotides. This interaction not only activates the F signals but also produces distinct signatures for each specific component, thereby enabling precise identification and quantification of molecules in evolving samples.

Synthesis of Diaryl Ethers via Hypervalent Iodine-Mediated C-H Functionalization.

A hypervalent iodine-reagent-based C-H functionalization strategy was utilized to synthesize diaryl ethers. This method directly transforms various arenes into their corresponding diaryliodonium salts, followed by a C-O coupling reaction to produce structurally diverse diaryl ethers. The efficacy of this approach in the late-stage structural modifications of complex molecules was demonstrated.

Tailoring the Performance of F-Labeled Probes via Dynamic Covalent Chemistry for Improved Chiral Discrimination.

This work presents a novel strategy for postmodifying probes using dynamic covalent chemistry. Leveraging reversible interactions between boronic acid and diols, we obtained a panel of F-labeled probes with distinct resolving abilities. This approach enables rapid identification of probes with satisfactory performance, streamlining synthesis, and enhancing efficiency in chiral analysis.

NMR-Based Chiral Discrimination of Bulky Amines with a F-Tagged NNO Pincer Complex.

Within pharmaceutical research, ensuring the enantiomeric purity of chiral compounds is critical. Specifically, chiral amines are a crucial category of compounds, due to their extensive therapeutic uses. However, the enantiomeric analysis of these compounds, particularly those with significant steric hindrance, remains a challenge.

A high-performance chiral F-labeled probe with an increased structural twisting.

We developed a new strategy to enhance the chiral discrimination capability of F-labeled probes by tuning the torsion angle of the probe's backbone, allowing for the resolution of challenging analytes. Its versatility is demonstrated through the superior performance and the wide analyte scope.

Detection and Identification of Nitrile Compounds via Recognition-Enabled Chromatographic F NMR.

The surge in applications of nitrile compounds across diverse fields, such as pharmaceuticals, agrochemicals, dyes, and functional materials, necessitates the development of rapid and efficient detection and identification methods. In this study, we introduce a chemosensing strategy employing a novel F-labeled probe, facilitating swift and accurate analysis of a broad spectrum of nitrile-containing analytes. This approach leverages the reversible interaction between the F-labeled probe and the analytes to produce chromatogram-like outputs, ensuring the precise identification of various pharmaceuticals and pesticides within complex matrices.

Conformational Locking as a Strategy to Reverse Ion Recognition Selectivity.

This study delves into the ion recognition capabilities of a novel host molecule, emphasizing the role of conformational locking in dictating ion selectivity. By employing the Buchwald-Hartwig cross-coupling reaction, we have notably shifted the ion receptor's selectivity from K to Na. The findings are supported by computational simulations that reveal differences in binding energies and molecular strain impacting ion recognition.

Bioinspired Organic Porous Coupling Agent for Enhancement of Nanoparticle Dispersion and Interfacial Strength.

Composite materials have significantly advanced with the integration of inorganic nanoparticles as fillers in polymers. Achieving fine dispersion of these nanoparticles within the composites, however, remains a challenge. This study presents a novel solution inspired by the natural structure of .

Chiral Discrimination of Acyclic Secondary Amines by F NMR.

Chiral aliphatic amine compounds exhibit a range of physiological activities, making them highly sought-after in the pharmaceutical industry and biological research. One notable obstacle in studying these compounds stems from the pronounced steric hindrance surrounding the nitrogen atom. This characteristic often leads to a weak affinity of acyclic secondary amines for molecular probes, making their chiral discrimination intricate.

Improving the Sensitivity of Enantioanalysis with Densely Fluorinated NMR Probes.

Nuclear magnetic resonance (NMR) spectroscopy has long been utilized as a classic method for chiral discrimination of enantiomers. However, its sensitivity limitations have hindered the detection of analytes at low concentrations. In this study, we present our efforts to overcome this challenge by employing chiral NMR probes that are labeled with a significant number of chemically equivalent F atoms.

Chiral Discrimination of Nitrile Compounds Using a F-Labeled Palladium Probe.

This study presents a F-labeled cyclopalladium probe for the rapid discrimination of chiral nitriles in pharmaceuticals, natural products, and agrochemicals. The probe binds reversibly to chiral nitriles, generating distinct F nuclear magnetic resonance signals for each enantiomer and enabling quick determination of enantiocomposition. The method allows for simultaneous detection of seven pairs of enantiomeric nitriles and application in assessing the enantiomeric excess of an asymmetric C-H cyanation reaction.

Chirality Sensing of N-Heterocycles via F NMR.

Methods to rapidly detect and differentiate chiral N-heterocyclic compounds become increasingly important owing to the widespread application of N-heterocycles in drug discovery and materials science. We herein report a F NMR-based chemosensing approach for the prompt enantioanalysis of various N-heterocycles, where the dynamic binding between the analytes and a chiral F-labeled palladium probe create characteristic F NMR signals assignable to each enantiomer. The open binding site of the probe allows the effective recognition of bulky analytes that are otherwise difficult to detect.

Tailoring the Recognition Property of a F-Labeled Gallium-Based NMR Probe: The Influence of the Metal Center.

Chirality is a fundamental property of nature and an essential element of the life process. As the biological activities, metabolic pathways, and toxicity of individual enantiomers are often varied, methods to rapidly and accurately discriminate chiral analytes are in great demand. Here, we report a F-labeled gallium-based probe for the enantiodifferentiation of chiral monoamines, diamines, amino alcohols, amino acids, and -heterocycles.

F-Labeled Probes for Recognition-Enabled Chromatographic F NMR.

The NMR technique is among the most powerful analytical methods for molecular structural elucidation, process monitoring, and mechanistic investigations; however, the direct analysis of complex real-world samples is often hampered by crowded NMR spectra that are difficult to interpret. The combination of fluorine chemistry and supramolecular interactions leads to a unique detection method named recognition-enabled chromatographic (REC) F NMR, where interactions between analytes and F-labeled probes are transduced into chromatogram-like F NMR signals of discrete chemical shifts. In this account, we summarize our endeavor to develop novel F-labeled probes tailored for separation-free multicomponent analysis.

Regioselective Aromatic Perfluoro--butylation Using Perfluoro--butyl Phenyl Sulfone and Arynes.

The selective introduction of perfluoro--butyl group (PFtB, the bulkier analogue of CF group) into arenes has long been sought after but remains a formidable task. We herein report the first general synthetic protocol to realize aromatic perfluoro--butylation. The key to the success is the identification of PFtB phenyl sulfone as a new source of PFtB anion, which reacts with arynes in a highly regioselective manner to afford perfluoro--butylated arenes in high yields.

Side-Chain Length and Dispersity in ROMP Polymers with Pore-Generating Side Chains for Gas Separations.

Bottlebrush polymers with flexible backbones and rigid side chains have shown ultrahigh CO permeability and plasticization resistance for membrane-based gas separations. To date, this class of polymers has only been studied with polydisperse side chains. Herein, we report gas transport properties of a methoxy (OMe) functionalized polymer synthesized via ring-opening metathesis polymerization (ROMP) with uniform side-chain lengths ranging from = 2 to 5 repeat units to elucidate the role of both side-chain length and dispersity on gas transport properties and plasticization resistance.

Dispersive 2D Triptycene-Based Crystalline Polymers: Influence of Regioisomerism on Crystallinity and Morphology.

The merging of good crystallinity and high dispersibility into two-dimensional (2D) layered crystalline polymers (CPs) still represents a challenge because a high crystallinity is often accompanied by intimate interlayer interactions that are detrimental to the material processibility. We herein report a strategy to address this dilemma using rationally designed three-dimensional (3D) monomers and regioisomerism-based morphology control. The as-synthesized CPs possess layered 2D structures, where the assembly of layers is stabilized by relatively weak van der Waals interactions between C-H bonds other than the usual π-π stackings.

Recognition-Enabled Automated Analyte Identification via F NMR.

Nuclear magnetic resonance (NMR) is an indispensable tool for structural elucidation and noninvasive analysis. Automated identification of analytes with NMR is highly pursued in metabolism research and disease diagnosis; however, this process is often complicated by the signal overlap and the sample matrix. We herein report a detection scheme based on F NMR spectroscopy and dynamic recognition, which effectively simplifies the detection signal and mitigates the influence of the matrix on the detection.

Toward Nanomolar Multi-Component Analysis by F NMR.

The widespread application of nuclear magnetic resonance (NMR) spectroscopy in detection is currently hampered by its inherently low sensitivity and complications resulting from the undesired signal overlap. Here, we report a detection scheme to address these challenges, where analytes are recognized by F-labeled probes to induce characteristic shifts of F resonances that can be used as "chromatographic" signatures to pin down each low-concentration analyte in complex mixtures. This unique signal transduction mechanism allows detection sensitivity to be enhanced by using massive chemically equivalent F atoms, which was achieved through the proper installation of nonafluoro--butoxy groups on probes of high structural symmetry.

Metal-Free C-H Functionalization via Diaryliodonium Salts with a Chemically Robust Dummy Ligand.

A two-step strategy for the transition-metal-free C-H functionalization of arenes using unsymmetrical iodonium salts as versatile synthetic linchpins is presented. The key to the success of this strategy is the identification of the 3,5-dimethyl-4-isoxazolyl (DMIX) group as a superior dummy ligand, which enables not only site-selective C-H functionalization to afford unsymmetrical iodonium salts, but also highly selective aryl transfer during the subsequent metal-free coupling reaction. Both electron-rich and moderately electron-deficient arenes can be converted into the iodonium salts through C-H functionalization, allowing for diverse structural elaboration by metal-free C-N, C-C, C-S, and C-O coupling.

Construction of Lewis Pairs for Optimal Enantioresolution via Recognition-Enabled "Chromatographic" F NMR Spectroscopy.

Chirality is a ubiquitous phenomenon in nature, serving as a foundation for a variety of life activities on earth. Separation-free methods that rapidly and accurately distinguish chiral analytes in complex systems are highly demanded in fields ranging from drug quality control to the screening of privileged chiral catalysts. However, in situ enantidifferentiation methods possessing resolution and tunability that are comparable to those achieved by chiral high-performance liquid chromatography are rare.

Calix[4]trap: A Bioinspired Host Equipped with Dual Selection Mechanisms.

Regulation of recognition events evolving in time and space is vital for living organisms. During evolution, organisms have developed distinct and orthogonal mechanisms to achieve selective recognition, avoiding mutual interference. Although the merging of multiple selection mechanisms into a single artificial host may lead to a more adaptable recognition system with unparalleled selectivity, successful implementation of this strategy is rare.