Solvent effects on blue shifted improper hydrogen bond of C-H⋯O in deoxycytidine isomers

Vibrational spectra of 2'-deoxycytidine (2'-dC) and 3'-deoxycytidine (3'-dC) are simulated with a number of polar and non-polar solvents. Significant spectral changes of the isomers indicate the unique hydrogen bond networks and their interactions with solvents. Vibrations such as C(4')-H stretch undergo improper blue shift of 103 cm ^-1 (vacuum), when associated with the C-H⋯O hydrogen bond network. Solvents red shift the IR spectra with respect to vacuum and reduce the improper blue shift, but do not change the nature of the shift (red or blue). Polarity of the solvents affects the spectral shift in a non-linear manner but the spectral shift becomes saturated in strong polar solvents.