Chirality最新文献

The synthesis, structure, and circularly polarized luminescence (CPL) properties of axially chiral boron difluoride complexes are described. A series of optically pure bis (boron difluoride) complexes were prepared in 5 steps from commercially available (S)- or (R)-BINOL as starting materials. The complexes were found to exhibit similar yellow photoluminescence in solution, regardless of the type of substituents on the nitrogen atoms. Notably, for the complex with polyethylene glycol chains, homogeneous and transparent films were formed by the drop-cast method, showing intense CPL with a different sign from that of the solution state. Density functional theory (DFT) calculations were performed to understand their photophysical behavior including configuration-dependent CPL properties.

A vibrational circular dichroism (VCD) instrument having a thermoelectrically cooled detector (denoted as a TEC unit) was constructed in this study. An electronic device, instead of liquid nitrogen, was employed in the instrument to cool the detector. The feasibility of the system was examined by recording the VCD spectra of liquid pinenes and insect wings. VCD signals were obtained at a constant baseline that was stable for more than 40 h. The spectrometer equipped with a TEC unit exhibited potential for performing measurements for prolonged time periods.

Chiral pesticides often undergo enantioselective degradation during food fermentation. In this study, the enantioselective fates of seven chiral pesticides during processing of wine and rice wine were investigated. The results revealed that R-metalaxyl, R-mefentrifluconazole and S-hexaconazole were preferentially degraded during wine processing with EF values of 0.57, 0.78, and 0.43, respectively, whereas S-metalaxyl and R-hexaconazole were preferentially degraded during rice wine processing with EF values of 0.44 and 0.54, respectively. Stereoselectivity was attributed to fermentative bacterial activity. The processing factor (PF) values for the five pesticides ranged from 0.04 to 0.34 during wine processing and from 0.02 to 0.29 during rice wine processing, suggesting that fermentation can mitigate pesticide exposure risks and ensure food safety. This study enhances our understanding of enantioselective fate of chiral pesticides during fermented food processing, provides guidance for the application of chiral pesticides, and enables the dietary risk of chiral pesticides in processed products to be assessed more accurately.

Efficient enantioselective separation is a critical process in pharmaceutical and chemical industries for the production of chiral compounds. Herein, we developed a novel approach for the efficient enantioselective separation of primary amines using supercritical fluid chromatography (SFC) with a commercially available SFC column, Cel1. The key factors of separation, including cosolvent ratios, total cosolvent percentages, and temperature, were systematically assessed in this study. It revealed that utilization of a cosolvent mixture consisting of methanol and isopropanol in a 1:3 (v/v) ratio with a low total cosolvent percentage of 5% resulted in superior retention and selectivity. Additionally, it was observed that maintaining mid-range temperatures at 30 and 35°C achieved optimal balance between retention and efficiency. Employment of commercially available SFC columns streamlined the separation process, reducing analysis time and labor. This study highlights the effectiveness of SFC as a powerful tool for conducting high-throughput enantioselective separations in pharmaceutical and fine chemical industries.

Enantiomeric analysis of chiral drugs is very significant, as their enantiomers display different pharmacological or toxicological behavior towards living systems. Among these drugs, β-blockers are available as racemates, where their enantiomers display different pharmacological effects. Herein, we report enantioselective separation of two β-blockers, namely, atenolol and sotalol, using a derivatization approach. The analytes were derivatized with “(S)-1-[1H-benzo(d)(1,2,3)triazol-1-yl]-2-[6-methoxynaphthalen-2-yl-propan-1-one]” {(S)-BTMNP} in a straightforward derivatization step. The resulting diastereomers were separated on a reverse-phase HPLC C18 column with a mobile phase composed of acetonitrile and TEAP buffer (75:25, v/v, pH = 3.5) and detection at 230 nm. This method achieved successful enantiomer separation for both drugs within 20 min, yielding resolution values greater than 3.8. The detection limits were determined to be 6.4 and 4.6 ng mL⁻¹ for atenolol and sotalol, respectively, which indicated sensitivity and effectiveness of the method for the analysis of two β-blockers from their dosage formulations.

A chiral porous organic polymer (cPOP) was synthesized through nucleophilic substitution polymerization between dichloromaleimide and aromatic amine. This cPOP was used as a new chiral stationary phase (CSP) for gas chromatography (GC) chiral separation. In this work, we first used this cPOP as the CSP for gas chromatography to investigate its ability to separate racemic mixtures, including amino acid derivatives, chiral alcohols, aldehydes, alkanes, ketones, esters, and organic acids. The results showed that the column can effectively separate various racemic mixtures and achieve baseline separation of threonine (Rs = 1.91). Furthermore, the separation mechanism was elucidated by density functional theory (DFT) simulation. Additionally, the cPOP column demonstrated good repeatability and stability. The relative standard deviations (RSDs) for intraday were 0.11%–0.12% (n = 3) for the retention time of n-butyl glycidyl ether, 0.1%–0.34% (n = 3) for interday, and 2.25%–3.37% (n = 3) for column to column. This work shows that cPOP has good potential as chiral stationary phases in gas chromatography.

Magnetic circularly polarized luminescence (MCPL) spectroscopy is widely used to evaluate the luminescence dissymmetry factor (g_MCPL) for compounds. However, even for the same instrument and operating conditions, the measured g_MCPL is affected by errors associated with sources such as baseline drift and spectral noise, and so the range of variation of g_MCPL must be considered when comparing values, which requires multiple measurements for the same sample. Also, because many samples undergo photodegradation under excitation light, it is difficult to accumulate and average spectra for samples with weak MCPL signals to improve the signal-to-noise ratio. Single measurements must therefore be performed on multiple samples and the results averaged. Furthermore, for samples with a small Stokes shift, spectral correction is required to compensate for the intensity reduction due to the inner-filter effect (IFE). Such measurements are generally performed manually and are therefore time consuming and prone to human error. Here, we demonstrate the use of a newly developed high-throughput MCPL system to automatically measure MCPL and fluorescence spectra of multiple samples of phthalocyanine complexes with high efficiency and reduced human errors. This system allows the incorporation of effective countermeasures to the issues of g_MCPL variation, sample photodegradation, extremely weak MCPL signals, and the IFE.