Linked Life Data

17134233

Source:http://linkedlifedata.com/resource/pubmed/id/17134233

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
48
pubmed:dateCreated
2006-11-30
pubmed:abstractText
We characterized anionic states of thymine using various electronic structure methods, with the most accurate results obtained at the CCSD(T)/aug-cc-pVDZ level of theory followed by extrapolations to complete basis set limits. We found that the most stable anion in the gas phase is related to an imino-oxo tautomer, in which the N1H proton is transferred to the C5 atom. This valence anion, aT(c5)(nl), is characterized by an electron vertical detachment energy (VDE) of 1251 meV and it is adiabatically stable with respect to the canonical neutral nT(can) by 2.4 kcal/mol. It is also more stable than the dipole-bound (aT(dbs)(can)), and valence anion aT(val)(can) of the canonical tautomer. The VDE values for aT(dbs)(can)and T(val)(can) are 55 and 457 meV, respectively. Another, anionic, low-lying imino-oxo tautomer with a VDE of 2458 meV has a proton transferred from N3H to C5 aT(c5)(n3). It is less stable than aT(val)(can) by 3.3 kcal/mol. The mechanism of formation of anionic tautomers with the carbons C5 or C6 protonated may involve intermolecular proton transfer or dissociative electron attachment to the canonical neutral tautomer followed by a barrier-free attachment of a hydrogen atom to C5. The six-member ring structure of the anionic tautomers with carbon atoms protonated is unstable upon an excess electron detachment. Within the PCM hydration model, the low-lying valence anions become adiabatically bound with respect to the canonical neutral; becomes the most stable, being followed by aT(c5)(nl), aT(c5)(n3), aT(can), and aT(c5)(nl).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1520-6106
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
110
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
24696-707
pubmed:dateRevised
2007-3-23
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
On the unusual stability of valence anions of thymine based on very rare tautomers: A computational study.
pubmed:affiliation
Faculty of Chemistry, University of Gda?sk, Sobieskiego 18, 80-952 Gda?sk, Poland.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't