Molecular structures of thymidine isomers isolated in low-temperature inert matrices

Abstract

The Fourier transform infrared spectra of 2′-deoxyribonucleoside–thymidine (dT) in low-temperature Ar matrices are obtained in the range 4000–1300 cm−1. It is determined that anti-conformers of thymidine are dominant. The ribose rings of the main anti-conformers dT_a0, dT_a1 are in the C2′-endo conformation, but the ribose rings of minor anti-conformers dT_a2, dT_a3 have the C3′-endo conformation, stabilized by intramolecular hydrogen bonds O3′H…O5′ and O5′H…O3′, respectively. The main syn-conformer dT_s2 is stabilized by the intramolecular hydrogen bond O5′H…O2 and has C2′-endo conformation of the ribose ring.