Ultrafast IR spectroscopy of the short-lived transients formed by UV excitation of cytosine derivatives

A strong infrared band at 1574 cm(-1) is observed following 267 nm excitation of 2'-deoxycytidine ( tau = 37 +/- 4 ps) or 2'-deoxycytidine 5'-monophosphate ( tau = 33 +/- 4 ps); this band is provisionally attributed to an (1)n(N)pi* state and is absent for cytosine.