Change search
ReferencesLink to record
Permanent link

Direct link
A Density Functional Theory Study of Hydrogen Transfer and Rotational Barriers in Vitamin E-like Molecules
Norwegian University of Science and Technology, Faculty of Natural Sciences and Technology, Department of Physics.
2011 (English)MasteroppgaveStudent thesis
Abstract [en]
A study of the antioxidant property of two vitamin E simplifications with density functional theory has been done. In one of the simplifications the phytyl tail and the methyl group on the heterocyclic ring in vitamin E is replaced by two hydrogen atoms, simplification A. In the other simplification the heterocyclic ring is replaced by two hydrogen atoms, simplification B. Three main investigations have been done; rotation of the hydroxyl group on the different isoforms of the two simplifications, hydrogen transfers from the alpha-isoform of the simplifications to three different radicals •OOH, •OOCH3, and •OOC2H5, and a rotation of the hydroxyl group with a hydrogen bond to •OOH and •OOCH3 for simplification B. The BLYP exchange correlation functional is found to underestimate hydrogen transfer energy barriers, which is improved with the B3LYP functional. This problem did not occur for the rotation of the hydroxyl group. The energy barriers for the rotation of the hydroxyl group is found to be smallest for the alpha-isoform, and simplification A gives lower rotational barriers than simplification B. Simplification A also results in smaller energy barriers for hydrogen transfers. The hydrogen transfer to •OOC2H5 with the B3LYP functional resulted in hydrogen barriers of 0,411 eV for simplification B and 0,231 eV for simplification A. Thus simplification B is found to be less reactive than simplification A, which is explained by the electron donating property of the heterocyclic ring not included in simplification B. Since simplification B is less reactive than simplification A, it is concluded to be a poorer antioxidant than simplification A, and a poor model for vitamin E.
Place, publisher, year, edition, pages
Institutt for fysikk , 2011. , 99 p.
Keyword [no]
ntnudaim:5843, MLREAL Lektorutdanning med master i realfag, Fysikk og matematikk
Identifiers
URN: urn:nbn:no:ntnu:diva-12798Local ID: ntnudaim:5843OAI: oai:DiVA.org:ntnu-12798DiVA: diva2:424968
Supervisors
Available from: 2011-06-20 Created: 2011-06-20

Open Access in DiVA

fulltext(5521 kB)1006 downloads
File information
File name FULLTEXT01.pdfFile size 5521 kBChecksum SHA-512
866d01b4b18ca7afb6b731d8e73e1dba10aca9b3b242a769b8177326588fd2973e27f3ba52b11edfb67b960a95227cacf952975ed60b9c7c3b2fac8877dbe025
Type fulltextMimetype application/pdf
cover(79 kB)29 downloads
File information
File name COVER01.pdfFile size 79 kBChecksum SHA-512
afb1de80bb883f1b7b52edf6a094c059f4f43f868339741efb1e60904a99221c8914e53b93acdaaef75df12a593ff8796bbf17b4425997c68137584971c42354
Type coverMimetype application/pdf

By organisation
Department of Physics

Search outside of DiVA

GoogleGoogle Scholar
Total: 1006 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 84 hits
ReferencesLink to record
Permanent link

Direct link