Conformational structures and vibrational spectra of isolated pyrimidine nucleosides: Fourier transform infrared matrix isolation study of 2-deoxyuridine.
The conformational structures of 2-deoxyuridine (dU) were investigated using Fourier transform infrared (FTIR) matrix isolation spectroscopy. For the first time the FTIR spectra of dU in Ar matrices were obtained in the range 4000-200 cm(-1). The stabilities of conformers were estimated by the methods HF/3-21G (p), HF/6-31G (d,p) and MP2/6-31G (d,p). Ab initio calculations of the infrared spectra were performed by the methods HF/3-21G (p) and HF/6-31G (d,p). The actual occupancy of conformational isomers in matrix samples was determined. It was shown that anti-conformers of dU are dominant. The ribose rings of the main anti-conformers dU _a0, dU _a1 are in the C2'-endo conformation, but the ribose rings of minor anti-conformers dU_a2, dU_a3 have the C3'-endo conformation, stabilized by intramolecular hydrogen bonds O3'H...O5' and O5'H...O3', accordingly. Syn-conformers of dU are stabilized by the intramolecular hydrogen bond O5'H...O2 and the dominant conformation of the ribose ring is C2'-endo.
Ivanov
A Yu
AY
Institute for Low Temperature Physics and Engineering, Ukrainian Academy of Sciences, Lenin Avenue 47, 310103 Kharkov, Ukraine. ivanov@ilt.kharkov.ua
Krasnokutski
S A
SA
Sheina
G
G
Blagoi
Yu P
YP
D002623:Chemistry Techniques, Analytical / Q000379:methods*; D019295:Computational Biology / Q000379:methods; D003857:Deoxyuridine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D003857:Deoxyuridine