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This paper discusses hyperconjugative stereoelectronic effects in borazines. A series of alkyl-substituted borazines were synthesized and analysed by NMR spectroscopy and X-ray diffraction. Supported by NBO analyses, the significant decreases in coupling constant for the CH groups adjacent to the boron atoms are consistent with the presence of and interactions. These interactions lower the electrophilicity of boron atoms, enhancing moisture stability and establishing these molecules as valuable scaffolds in synthetic chemistry and materials science.
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http://dx.doi.org/10.1039/d4cc05188b | DOI Listing |
Phys Chem Chem Phys
August 2025
Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea.
Pyridine derivatives are integral to fields such as organic chemistry, materials science, and pharmaceuticals owing to their distinct electronic and structural properties. While fluorine substitution on the pyridine ring is known to modulate these properties, the specific effects of fluorine positioning-particularly at the and positions-on the molecular orbitals, ionization energies, and cationic structures remain insufficiently understood. In this study, we investigate the ionization-induced structural dynamics of 2,3-difluoropyridine (2,3-DFP), which incorporates both - and -fluorine substituents, using high-resolution vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy in conjunction with Franck-Condon (FC) simulations and natural bond orbital analysis.
View Article and Find Full Text PDFBeilstein J Org Chem
April 2025
School of Chemistry, The University of New South Wales (UNSW), Sydney 2052, Australia.
When present within an organic molecule, the C-F bond tends to align in predictable ways with neighbouring functional groups, due to stereoelectronic effects such as hyperconjugation and electrostatic attraction/repulsion. These fluorine-derived conformational effects have been exploited to control the shapes, and thereby enhance the properties, of a wide variety of functional molecules including pharmaceutical agents, liquid crystals, fragrance chemicals, organocatalysts, and peptides. This comprehensive review summarises developments in this field during the period 2010-2024.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Institute of Organic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 38, 1090, Vienna, Austria.
This paper discusses hyperconjugative stereoelectronic effects in borazines. A series of alkyl-substituted borazines were synthesized and analysed by NMR spectroscopy and X-ray diffraction. Supported by NBO analyses, the significant decreases in coupling constant for the CH groups adjacent to the boron atoms are consistent with the presence of and interactions.
View Article and Find Full Text PDFJ Am Chem Soc
September 2023
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
In order to use holes as catalysts, the oxidized product should be able to transfer the hole to a fresh reactant. For that, the hole-catalyzed reaction must increase the oxidation potential along the reaction path, i.e.
View Article and Find Full Text PDFJ Am Chem Soc
May 2023
Shenzhen Grubbs Institute, Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
Conjugated molecules play a critical role in the construction of single-molecule devices. However, most conventional conjugated molecules, such as hydrocarbons, involve only a pπ-pπ conjugation of light elements. While the metal d-orbitals can introduce abundant electronic effects to achieve novel electronic properties, it is very scarce for the charge transport study of dπ-pπ conjugated pathways with a metal involved.
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