The chiral separations of small peptides is an important challenge in the biological and medical sciences, because different stereoisomers of chiral drugs can often possess different pharmacological, pharmacokinetic, and/or toxicological activities. Commercially available crown ether chiral stationary phases based on S-(3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 (CROWNPAK CR-I (+)) and (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (ChiroSil RCA (+)) have been successfully used for separating enantiomers of various racemic compounds containing primary amino groups. In this investigation, enantioresolution of more complex model analyte - tetrapeptide Tyr-Arg-Phe-Lys-NH, has been reported on crown ether chiral stationary phases. Organic and acidic modifier content in aqueous mobile phase was tested. All Tyr-Arg-Phe-Lys-NH stereoisomers showed U-shaped retention plots, based on ACN content in mobile phase. Increased retention of tetrapeptide stereoisomers was observed at low (<35%) and at high (>70%) acetonitrile content in the mobile phase, indicating that different separation mechanisms are most likely involved. As a result, baseline separation of all eight tetrapeptide enantiomer pairs was achieved under isocratic elution mode on both chiral columns.
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http://dx.doi.org/10.1016/j.chroma.2020.461152 | DOI Listing |
Chem Commun (Camb)
January 2025
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China.
The electroconversion of CO into ethylene (CH) offers a promising solution to environmental and energy challenges. Crown ether (CE) modification significantly enhances the CH selectivity of copper-based MOFs, improving CH faradaic efficiency (FE) in CuBTC, CuBDC, and CuBDC-NH by 3.1, 1.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada; Quebec Centre for Advanced Materials (QCAM) and Pulp and Paper Research Centre, McGill University, 3420 University Street, Montreal, QC H3A 2A7, Canada. Electronic address:
The synergy between nanomaterials as solid supports and supramolecular concepts has resulted in nanomaterials with hierarchical structure and enhanced functionality. Herein, we developed and investigated innovative supramolecular functionalities arising from the synergy between organic moieties and the preexisting nanoscale soft material backbones. Based on these complex molecular nano-architectures, a new nanorod carbohydrate polymer carrier was designed with bifunctional hairy nanocellulose (BHNC) to reveal dual-responsive advanced drug delivery (ADD).
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Pennsylvania, 231 S 34th St, Philadelphia, Pennsylvania 19104, United States.
Molecular Zr phosphides are extremely rare, with no examples containing a one-coordinated and terminal triple-bonded phosphorus atom. We report here an isolable and relatively stable Zr phosphide complex, [(PN)Zr≡P{μ-Na(OEt)}] (), stemming from a cyclometalated Zr-hydride, [(PN)(PN')Zr(H)] (), and NaPH. Complex is prepared from two- or one-electron reductions of precursors [(PN)ZrCl] () or metastable Zr[(PN)ZrCl], respectively.
View Article and Find Full Text PDFDalton Trans
January 2025
School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, 330031, People's Republic of China.
Three-component crown ether phase change materials are characterized by a structural phase change in response to external stimuli such as temperature and electric or magnetic fields, resulting in significant changes in physical properties. In this work, we designed and synthesized two novel host-guest crown ether molecules [(PTFMA)(15-crown-5)ClO] (1) and [(PTFMA)(15-crown-5)PF] (2), through the reaction of -trifluoromethylaniline (PTFMA) with 15-crown-5 in perchloric acid or hexafluorophosphoric acid aqueous solution. Compound 1 undergoes a structural change from the non-centrosymmetric space group (2) to the centrosymmetric space group (2/) with increasing temperature.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
College of Chemistry and Molecular Sciences, Henan University, Kaifeng, 475004, China.
Cycloparaphenylenes (CPPs) represent a significant challenge for the synthesis of mechanically interlocked architectures, because they lack heteroatoms, which precludes traditional active and passive template methods. To circumvent this problem and explore the fundamental and functional properties of CPP rotaxanes and catenanes, researchers have resorted to unusual non-covalent and even to labor-intensive covalent template approaches. Herein, we report a ring-in-ring non-covalent template strategy that makes use of the surprisingly strong non-covalent inclusion of crown ethers into suitably sized CPPs.
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