English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Experimental and computational analysis of spectroscopic parameters of L-ascorbic acid (vitamin C) and its tautomers was investigated by Density Functional Theory (DFT) using B3LYP method. The optimized geometries and calculated vibrational frequencies were evaluated. The latter was compare with those of experimental values. The λ max values of L-ascorbic acid were found 259 (at pH = 3) experimentally, 238 and 247 nm calculated in the gas and water phase at TD-DFT methods, respectively. The experimental order of υ(O-H) modes was obtained at υ(O 3 –H 3 ) > (O 6 –Ho 6 ) > (O 2 –H 2 ) > (O 5 –Ho 5 ). The theoretical orders were calculated at υ)O 6 –Ho 6 ) > (O 2 –H 2 ) > (O 5 –Ho 5 ) > (O 3 –H 3 ( and υ(O 3 –H 3 ) > (O 5 –Ho 5 ) > (O 6 –Ho 6 ) > (O 2 –H 2 ), respectively, in the gas phase and aqueous phase. The highest wave number of tautomers (S,Z)-3,5,6-trihydroxy-2-oxohex-3-enoic acid (2), (2Z,4E)-2,3,5,6-tetrahydroxyhexa-2,4-dienoic acid (3), (R)-2-((S)-1,2dihydroxyethyl)-4,5-dihydroxyfuran-3(2H)-one (4) was calculated for the stretching modes O 6 -Ho 6 , O 3 -H 3 , O 6 -Ho 6 bonds, respectively, in the gas phase. The experimental and theoretical calculations of proton NMR predicted H 3 as the most deshilded proton.

UV-VIS, NMR AND FT-IR SPECTRA OF TAUTOMERS OF VITAMIN C. EXPERIMENTAL AND DFT CALCULATIONS