| Popis: |
The nitrile functional group has been extensively investigated as a probe in proteins but not as a probe in nucleosides. The solvent-induced vibrational frequency shift of the nitrile band of 5-cyano-2′-deoxyuridine was examined in THF-H2O mixtures. The nitrile stretching frequency (νC≡N) exhibited moderate solvent sensitivity, undergoing a 9.2 cm-1 blue shift from THF to H2O, and varied linearly with temperature, exhibiting a 1.4 cm-1 red shift from 290 K to 340 K in H2O. The νC≡N of 5-cyano-2′-deoxy-3′,5′-bis-O-(t-BuPh2Si)-uridine underwent a 1.3 cm-1 blue shift when titrated with a base-pairing mimic, 2,6-diheptanamido-pyridine to yield an association constant of 90 M-1. The corresponding C15N labeled nucleoside is currently under investigation by 15N NMR to determine the utility of the C15N moiety as an NMR probe of the local environment of nucleic acids. Both the IR and NMR results will be presented complemented by density functional theory calculations. |
