Elucidating tricin-lignin structures: assigning correlations in HSQC spectra of monocot lignins
Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one] is a flavone that has been found to be incorporated in grass lignin polymers via 4′–O–β coupling. Herein, we investigated the tricin-lignin structure using nuclear magnetic resonance (NMR) methods by comparing the 1H–13C heteronuclear correlation (HSQC) NMR spectra of the isolated lignin with a series of dimeric and trimeric tricin-4′–O–β-ether model compounds. Results showed that the tricin moiety significantly affects the chemical shift of the Cβ/Hβ of 4′–O–β unit, producing peaks at around δC/δH 82.5–83.5/4.15–4.45, that differ from the Cβ/Hβ correlations from normal 4–O–β units formed solely by monolignols, and that have to date been unassigned.
Main Authors: | , , , , , , |
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Other Authors: | |
Format: | artículo biblioteca |
Published: |
Multidisciplinary Digital Publishing Institute
2018-08-15
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Subjects: | Tricin, Lignin, Model compound, HSQC, Nuclear magnetic resonance (NMR), Monocot, |
Online Access: | http://hdl.handle.net/10261/169021 http://dx.doi.org/10.13039/501100004543 http://dx.doi.org/10.13039/501100000780 http://dx.doi.org/10.13039/501100003329 http://dx.doi.org/10.13039/100007015 http://dx.doi.org/10.13039/501100010198 http://dx.doi.org/10.13039/100000138 http://dx.doi.org/10.13039/501100011033 http://dx.doi.org/10.13039/100000015 |
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