Aldehyde and ketone adducts of the gaseous trifluoromethyl cation

IR spectra of CF(3)(+) adduct ions are reported for the first time using infrared multiple photon dissociation (IRMPD). Carbonyl stretches of ketone conjugate acids shift less than do those of ions containing C═OCF(3)(+) groups. Carbonyl absorptions shift in proportion to the empirical softness of the corresponding neutrals. Anharmonic DFT fits band positions of C═OCF(3)(+) stretches for aliphatic ions, but unscaled harmonic calculations match O-CF(3) stretches more closely. Calculated O-CF(3) bond orders increase with gas phase CF(3)(+) affinities of the corresponding neutral carbonyl.