| Abstract
| - The ribose and deoxyribose molecules of RNA and DNA nucleosides are substituted with simple modelcompounds 1-methoxy-2-ethanol and 1-methoxypropane to mimic the effect of binding to sugars on the verticalexcitation energies of purine and pyrimidine bases. The (R)-1-methoxy-2-ethanol, CH3OC*HCH2OH, formodel ribose nucleosides and (R)-1-methoxypropane, CH3OC*HC2H5, for model deoxyribose nucleosideshave minimal structural characteristics of ribose and deoxyribose molecules when attached to nucleic acidpurine and pyrimidine bases. The bases are attached to the C1 carbon atom designated by the asterisk. Thevertical excitation energies of these model nucleosides are calculated with the time-dependent density functionaltheory method at the B3LYP level with 6-311++G(d,p) and aug-cc-pVDZ basis sets. The attachment of theether molecules qualitatively and quantitatively modifies the excited state energy levels of the model nucleosideswhen compared to the free bases. These changes can affect the deexcitation mechanisms for photoexcitednucleosides.
|
