Ultraviolet resonance Raman spectra of ribosyl C(1')-deuterated purine nucleosides: evidence of vibrational coupling between purine and ribose rings

Ultraviolet resonance Raman spectra of ribosyl C(1')-deuterated guanosine and adenosine were measured. Most in-plane vibrations of the purine rings in the 1420-1100-cm -1 region showed frequency upshifts upon C(1')-deuteration, while those in the 1100-700-cm -1 region showed downshifts. The purine ring vibrations above 1450 cm -1 were unaffected. The frequency shifts associated with the C(1')-deuteration are explained by assuming couplings of the purine vibrations with a ribose C(1')-H bending mode, which involves a hydrogen motion in the plane of N(9)-C(1')-H