Computed association energies and dissected nucleus-independent chemical shifts (NICS) document the mutual enhancement (or reduction) of intermolecular interactions and the aromaticity of H-bonded substrates. H-bonding interactions that increase cyclic 4n + 2 π-electron delocalization boost aromaticity. Conversely, such interactions are weakened when aromaticity is decreased as a result of more localized quinoidal π character. Representative examples of the tautomeric equilibria of π-conjugated heterocyclic compounds in protic solvents and other H-bonding environments also illustrate such H-bonding/aromaticity interplay.
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http://dx.doi.org/10.1021/ja507202f | DOI Listing |
J Adv Res
December 2024
College of Horticulture, Nanjing Agricultural University, Nanjing 21095, China. Electronic address:
Introduction: 5-Aminolevulinic acid (ALA) is an essential biosynthetic precursor of tetrapyrrole compounds, naturally occurring in all living organisms. It has also been suggested as a new plant growth regulator. Treatment with ALA promotes strawberry Na homeostasis under salt stress.
View Article and Find Full Text PDFIUCrdata
October 2024
EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom.
The title di-thio-carbazate imine, CHNOS, was obtained from the condensation reaction of -methyl-dithio-carbazate (SMDTC) and 5-methyl-isatin. It shows a configuration about the imine C=N bond, which is associated with an intra-molecular N-H⋯O hydrogen bond that closes an (6) ring. In the crystal, inversion dimers linked by pairwise N-H⋯O hydrogen bonds generate (8) loops.
View Article and Find Full Text PDFMolecules
November 2024
Institute of Applied Radiation Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.
Pressurized high-temperature water attracts attention as a promising medium for chemical synthesis, biomass processing or destruction of hazardous waste. Adjustment to the desired solvent properties requires knowledge on the behavior of populations of hydrogen-bonded molecules. In this work, the interconnection between the hydrogen bond (HB) dynamics and the structural rearrangements of HB networks have been studied by molecular dynamics simulation using the modified central force flexible potential and the HB definition controlling pair interaction energy, HB length and HB angle.
View Article and Find Full Text PDFIn this study, characteristics of laser ignition of H/air mixtures are investigated in a constant-volume combustion chamber using a compact, passively Q-switched Nd:YAG/Cr:YAG laser spark plug. Ignition was conducted at a single point, with precise timing achieved through two laser modes of operation: delivering a single laser pulse and operating in pulse-burst mode, emitting trains of up to five laser pulses. Experiments covered a wide range of relative equivalence ratios (λ= 1.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
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