It was demonstrated that 9-aryl-substituted isoquinolinium derivatives have significantly increased fluorescence quantum yields in halogenated solvents, mostly pronounced in chloroalkanes, which appears to be specific for this type of solvents. Further analysis with selected halogenated solvents revealed that the type and number of halogen substituents and the dielectric constant of the solvent have a distinct impact on the emission quantum yield. The solvent effect is explained by a solvation of the charge shift (CS) state by attractive halogen-π interactions (halogen bond), which impedes the torsional relaxation of the excited state.
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http://dx.doi.org/10.1007/s10895-024-03691-z | DOI Listing |
Polymers (Basel)
December 2024
State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, China.
The presented work discusses the highly efficient esterification of poly (γ-glutamic acid) (γ-PGA) with alkyl halides at room temperature. The esterification reaction was completed within 3 h, and the prepared γ-PGA esters were obtained with excellent yields (98.6%) when 1,1,3,3-tetramethylguanidine (TMG) was used as a promoter.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Solid State Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic.
The most commonly used homogeneous catalyst for fatty acid esterification is a corrosive sulphuric acid. However, this requires costly investment in non-corrosive equipment, presents a safety risk, is time consuming, and increases effluent generation. In this study, inorganic 3D heteroborane cluster strong acids are employed for the first time as homogeneous catalysts.
View Article and Find Full Text PDFJ Org Chem
January 2025
Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149 Münster, Germany.
Xanthine nucleosides play a significant role in the expansion of the four-letter genetic code. Herein, 7-functionalized 8-aza-7-deazaxanthine ribo- and 2'-deoxyribonucleosides are described. 2-Amino-6-alkoxy nucleosides were converted to halogenated 8-aza-7-deazaxanthine nucleosides by deamination followed by hydroxy/alkoxy substitution.
View Article and Find Full Text PDFThe development of new protocols for stereospecific and stereoselective halogenation transformations by mild reaction conditions is a highly desirable research target for the chemical and pharmaceutical industries. Following the straightforward methodology for directly transforming a wide scope of alcohols to alkyl bromides and chlorides using substoichiometric amounts of thioureas and N-halo succinimides (NXS) as a halogen source in a single step, we noticed that in apolar solvents bromination of chiral secondary alcohols did not produce the expected racemates. In this study, the stereochemical aspects of the bromination reaction were examined.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, Faculty of Science, Ilam University, P.O. Box 69315516, Ilam, Iran.
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