Infrared and DFT Investigations of the XC⋮ReX3 and HC⋮ReX3 Complexes: Jahn−Teller Distortion and the Methylidyne C−X(H) Stretching Absorptions
摘要:
The XC ReX3 complexes (X = F, Cl) are produced by CX4 reaction with laser-ablated Re atoms, following oxidative C-X insertion and alpha-halogen migration in favor of the carbon-metal triple bond and are identified through the observation of characteristic absorptions in the argon matrix infrared spectra and comparison with vibrational frequencies calculated by density functional theory. The methylidyne C-F and C-Cl stretching absorptions are observed near 1584 and 1328 cm(-1), and the C-H stretching modes for HC ReX3 at 3104 and 3097 cm(-1), respectively, which are substantially higher than the precursor stretching modes and in agreement with the general trend that higher s-orbital character in carbon hybridization leads to a higher stretching frequency. The Jahn-Teller effect in the doublet-state XC ReX3 and HC ReX3 complexes gives rise to distorted structures with C-S symmetry and two equivalent longer Re-X bonds and one slightly shorter Re-X bond.