Товарлар кимёси ва халқ табобати 2-jild 6-son (2023) · 200-221-betlar
STEREOCHEMISTRY OF ENINE ALDEHYDES: BASED ON THE RESULTS OF X-RAY STRUCTURAL ANALYSIS, NUCLEAR MAGNETIC RESONANCE AND QUANTUM CHEMICAL CALCULATIONS
Abdulloev, Tohir Kh.
Annotatsiya
The study presents the research results aimed at developing conditions for synthesizing enyne dihydroxy aldehydes and identifying factors responsible for their conformational stability. The most effective oxidant for obtaining enyne dihydroxy aldehydes was found to be MnO₂. A comparison of the vibrational frequencies of acetylene, ethylene bonds, and the carbonyl group obtained for each of the isomers, considering quantum chemical calculations of the bond lengths and electron density distribution in the molecules, reveals that a decrease in bond order leads to greater conformational freedom of the molecules. Consequently, valence vibration frequencies are shifted to a higher region. For the studied conformations, the distribution of electron density (Mulliken charges) and the lengths of bonds involved in the conjugated system were calculated, uncovering changes in the multiplicity of carbon-carbon bonds. The results of the research using quantum chemical calculations allow for the assignment of IR and NMR spectra of the isomeric enynic dihydroxyaldehydes and the conclusion about the disruption of coplanarity in the conjugated system of the Z-isomer of the dihydroxyaldehyde. For instance, differences in the SSCC of the aldehyde proton with the nearby proton of the ethylene bond indicate a disruption of the coplanarity of the conjugated system in enynic dihydroxyaldehydes.
Ениновые диоксиальдегидысопряженная системаИК- и ПМР спектрымагнитная анизотропиястереохимияEnyne dihydroxyaldehydesconjugated systemIR and PMR spectramagnetic anisotropystereochemistry
Metadata manbasi: jurnal OAI-PMH arxivi · Sindex toʻliq matnni saqlamaydi, manbaga havola beradi.