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Organic semiconductor gas sensors are of great interest, owing to their promising advantages in room temperature operation and high selectivity. In the past decades, most relevant research focused on unipolar OFET-based sensors. Ambipolar transistors, with two types of charge carriers involved in the operation, provide further possibility for highly selective sensing. Herein, gas sensors based on an ambipolar OFET fabricated with a 2,5-bis(4-biphenylyl)bithiophene (BP2T) and copper hexadeca-fluorophthalocyanine (F16CuPc) bilayer are reported along with their response to several redox gases, including NO2, NH3, H2S and SO2. The ambipolar devices demonstrate clear dual response based on the current (or conductivity) signal, along with the great advantages of being multi-parameter, high output signal and better stability compared to unipolar transistors for sensing gases from NO2 to NH3. In addition, an obviously higher absolute signal change (ΔI, ΔV) could be observed with the ambipolar transistors, even for gases that are hard to detect using the BP2T or F16CuPc unipolar transistors such as SO2 or H2S. These advantages enable the ambipolar transistors to much more easily distinguish target gases with additional parameters, high sensitivity and good stability. [ABSTRACT FROM AUTHOR]

Novel chiral selectors based on 3,5‐dimethyl phenylcarbamoylated β‐cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5‐dimethyl phenylcarbamoylated β‐cyclodextrin (β‐CD) chiral stationary phase (CSP) and 9‐O‐(tert‐butylcarbamoyl)‐QN‐based CSP (QN‐AX). Fmoc‐protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD‐based CSP and QN/QD‐based CSPs have broader application range than β‐CD‐based CSP or QN/QD‐based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc‐amino acids accompanied by the synergistic effect of β‐CD moiety, which lead to the different enantioseparation of β‐CD‐QN‐based CSP and β‐CD‐QD‐based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin‐based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β‐CD‐based CSP for certain samples. [ABSTRACT FROM AUTHOR]

In this study, a series of chiral stationary phases based on N‐[(4‐methylphenyl)sulfonyl]‐l‐leucine amide, whose enantiorecognition property has never been studied, were synthesized. Their enantioseparation abilities were chromatographically evaluated by 67 enantiomers. The chiral stationary phase derived from N‐[(4‐methylphenyl)sulfonyl]‐l‐leucine showed much better enantioselectivities than that based on N‐(4‐methylbenzoyl)‐l‐leucine amide. The construction of C2 symmetric chiral structure greatly improved the enantiorecognition performance of the stationary phase. The C2 symmetric chiral stationary phase exhibited superior enantioresolutions to other chiral stationary phases for most of the chiral analytes, especially for the chiral analytes with C2 symmetric structures. By comparing the enantioseparations of the enantiomers with similar structures, the importance of hydrogen bond interaction, π–π interaction, and steric hindrance on enantiorecognition was elucidated. The enantiorecognition mechanism of trans‐N,N′‐(1,2‐diphenyl‐1,2‐ethanediyl)bis‐acetamide, which had an excellent separation factor on the C2 symmetric chiral stationary phase, was investigated by 1H‐NMR spectroscopy and 2D 1H‐1H nuclear overhauser enhancement spectroscopy. [ABSTRACT FROM AUTHOR]

As an important intermediate of prostaglandins and entecavir, optically pure Corey lactone diol (CLD) has great value in the pharmaceutical industry. In this work, the enantioseparation of (±)‐CLD was evaluated using high‐performance liquid (HPLC) and supercritical fluid chromatography (SFC). In HPLC, the separations of CLD enantiomers on polysaccharide‐based chiral stationary phases with both normal phase and polar organic phase were screened. And the conditions for the enantioseparation were optimized in HPLC and SFC, including the selection of mobile phase, temperature, back‐pressure, and other conditions. More important, it was found that the chiral resolutions were greatly enhanced by the increase of the coating amount of ADMPC (amylose tris‐(3,5‐dimethylphenylcarbamate)) under both HPLC and SFC conditions, which can lead to the increase of the productivity and the decrease of the solvent consumption. The preparations of optically pure CLD were evaluated on a semi‐preparative (2 × 25 cm) column packed with 30% ADMPC‐coated CSP under HPLC and SFC conditions. Preparative performances in terms of kkd are 1.536 kg racemate/kg CSP/day and 1.248 kg racemate/kg CSP/day in HPLC and SFC, respectively. [ABSTRACT FROM AUTHOR]

In this study, a series of chiral stationary phases based on N-[(4-methylphenyl)sulfonyl]-l-leucine amide, whose enantiorecognition property has never been studied, were synthesized. Their enantioseparation abilities were chromatographically evaluated by 67 enantiomers. The chiral stationary phase derived from N-[(4-methylphenyl)sulfonyl]-l-leucine showed much better enantioselectivities than that based on N-(4-methylbenzoyl)-l-leucine amide. The construction of C 2 symmetric chiral structure greatly improved the enantiorecognition performance of the stationary phase. The C 2 symmetric chiral stationary phase exhibited superior enantioresolutions to other chiral stationary phases for most of the chiral analytes, especially for the chiral analytes with C 2 symmetric structures. By comparing the enantioseparations of the enantiomers with similar structures, the importance of hydrogen bond interaction, π-π interaction, and steric hindrance on enantiorecognition was elucidated. The enantiorecognition mechanism of trans-N,N'-(1,2-diphenyl-1,2-ethanediyl)bis-acetamide, which had an excellent separation factor on the C 2 symmetric chiral stationary phase, was investigated by 1 H-NMR spectroscopy and 2D 1 H- 1 H nuclear overhauser enhancement spectroscopy., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)