A twisted X-ray beam with orbital angular momentum is employed in a theoretical study to probe molecular chirality. A nonlocal response description of the matter-field coupling is adopted to account for the field short wavelength and the structured spatial profile. We use the minimal-coupling Hamiltonian, which implicitly takes into account the multipole contributions to all orders. The combined interactions of the spin and orbital angular momentum of the X-ray beam give rise to circular-helical dichroism signals, which are stronger than ordinary circular dichroism signals, and may serve as a useful tool for the study of molecular chirality in the X-ray regime.
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http://dx.doi.org/10.1021/acs.jctc.9b00346 | DOI Listing |
J Am Chem Soc
December 2024
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Compared with chiral β-amino phosphorus compounds, which can be easily derived from natural optically pure α-amino acids, obtaining chiral β-amino phosphorus derivatives remains a challenge. These derivatives, which cannot be derived from chiral natural amino acids, possess unique biological activities or potential catalytic activities. Herein, highly enantioselective hydrogenation for the preparation of chiral β-amino phosphorus derivatives from -β-enamido phosphorus compounds is reported by using a green and low-cost earth-abundant metal nickel catalyst (13 examples of 99% ee).
View Article and Find Full Text PDFJ Agric Food Chem
December 2024
College of Plant Protection, Southwest University, Chongqing 400715, China.
Etoxazole, a widely used mite growth inhibitor, contains a chiral center in its chemical structure, resulting in two mirror-image enantiomers. These enantiomers of etoxazole display significant differences in biological activity and environmental behavior. In bioassays conducted against , it was observed that S-etoxazole demonstrated approximately 279.
View Article and Find Full Text PDFMar Drugs
November 2024
College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Republic of Korea.
Four previously undescribed pentacyclic triterpenoid saponins, pannosides F-I (-), were isolated from the halophyte L. (), and their chemical structures were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry. Comprehensive structural analysis revealed the presence of distinct aglycone and glycosidic moieties, along with complex acylation patterns.
View Article and Find Full Text PDFBiosensors (Basel)
December 2024
School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea.
Metal nanoclusters (NCs) are promising alternatives to organic dyes and quantum dots. These NCs exhibit unique physical and chemical properties, such as fluorescence, chirality, magnetism and catalysis, which contribute to significant advancements in biosensing, biomedical diagnostics and therapy. Through adjustments in composition, size, chemical environments and surface ligands, it is possible to create NCs with tunable optoelectronic and catalytic activity.
View Article and Find Full Text PDFJ Org Chem
December 2024
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
A palladium-catalyzed asymmetric chlorocyclization of 1,6-enynes has been described. Controlling the chloride ion concentration in the system by substrate design is the key to achieving asymmetric chlorinated cyclization. In the presence of Pd(PhCN)Cl and chiral phosphoramidite ligands, the reaction accesses diverse chiral ()-α-chloromethylene-γ-butyrolactams with excellent selectivity and enantioselectivity.
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