Chirality Sensing of N-Heterocycles via 19F NMR

19F NMR-Based Chiral Analysis of Organoboron Compounds via Chiral Recognition of Fluorine-Labeled Boronates with Cobalt Complexes

This study aims to develop a method for the chiral analysis of organoboron compounds using nuclear magnetic resonance (NMR) spectroscopy. It addresses the longstanding challenge associated with these chiral organoboron compounds, which often require derivatization and pretreatment prior to chromatographic analysis. Our method utilizes tridentate ligands to facilitate effective ligand exchange and incorporates fluorine labels, allowing for the precise discrimination of 19F NMR signals. This is achieved in conjunction with a chiral cationic cobalt complex, serving as the chiral solvating agent. This approach provides reliable and rapid determination of enantiomeric excess in a wide range of organoboron compounds, featuring various functional groups, and establishes a universal tool for assessing the optical purity of these substances.

High-efficiency detection of primary amine-based chiral molecules by a facile aldimine condensation reaction

Detection of chiral molecules in a high-efficiency way is very important to meet the demands for chiral analysis in drug testing, asymmetric synthesis, etc. Herein, we have developed a novel route to realize the rapid determination of concentration and configuration of primary amine-based chiral molecules. An aldehyde functionalized acid & base-sensitive fluorane dye (R-C) was used as the active agent to be reacted with the chiral molecules through an aldimine condensation reaction. After the mixing operation, concentration and configuration of the detected chiral molecule could be facilely read from the UV-vis absorption spectra and CD spectra, respectively.

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.

NMR-Based Chiral Discrimination of Bulky Amines with a 19F-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. To address this issue, our research introduces a novel chiral 19F-tagged NNO palladium pincer probe, strategically engineered with an open binding site to accommodate bulky amines. This probe facilitates the enantiodifferentiation of such amines, as evidenced by the distinct 19F NMR signals generated by the enantiomers. Moreover, our findings highlight the probe's applicability in the chiral discrimination of various psychoactive substances, underscoring its potential for the identification of illegal stimulant use and contributing to forensic investigations.

A high-performance chiral 19F-labeled probe with an increased structural twisting

We developed a new strategy to enhance the chiral discrimination capability of 19F-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 19F 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 19F-labeled probe, facilitating swift and accurate analysis of a broad spectrum of nitrile-containing analytes. This approach leverages the reversible interaction between the 19F-labeled probe and the analytes to produce chromatogram-like outputs, ensuring the precise identification of various pharmaceuticals and pesticides within complex matrices. Additionally, this dynamic system offers a versatile platform to investigate through-space 19F-19F interactions, showcasing its potential for future applications in mechanistic studies.

Chiral Discrimination of Acyclic Secondary Amines by 19F 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. In response to this challenge, our research has unveiled a novel 19F-labeled probe adept at recognizing and distinguishing between enantiomers of these acyclic secondary amines. By strategically incorporating a single fluorine atom as the 19F label, we have managed to diminish the steric hindrance at the binding site. This alteration bolsters the probe's affinity toward bulkier analytes. As a testament to its effectiveness, we have successfully employed our probe in the chiral analysis of relevant pharmaceuticals, accurately determining their enantiocomposition.

Chiral Discrimination of Nitrile Compounds Using a 19F-Labeled Palladium Probe

This study presents a ¹⁹F-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 ¹⁹F 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.