Absence of Hydrogen Bonding between HCo(CO)₄ and Nitrogen or Oxygen Bases. IR and Raman Study

HCo(CO)₄ has been observed by Raman spectroscopy in acetonitrile at −26 °C in the presence and absence of 2,4-dichloroanuine. Although HCo(CO)₄ is substantially deprotonated by the aniline, there is no evidence of a hydrogen bond between the excess aniline and the remaining hydride. Matrices containing HCo(CO)₄ and a polar molecule such as acetonitrile, water, ammonia, or trimethylamine have also been examined by infrared and Raman spectroscopy. Prior to proton transfer, which occurs on heating, there is little interaction between the base and the hydride ligand. The only observed perturbation of a vibrational mode was that of the H-Co deformation when the strongest base examined, Me₃N, was present. This evidence, along with the large infrared intensity of the deformation mode, suggests that the deformation coordinate may play a large role in the transfer of a proton from HCo(CO)₄.