C18O exchange studies on Mn(CO)5X systems (X = Cl or Br)

Abstract

The exchange of C¹⁸O with the CO groups of Mn(CO)₅Cl and Mn(CO)₅ Br has been studied by following the variation with time of the infrared spectra in the C–O stretching region. The C–O stretching frequencies for the isotopically substituted species which might have been produced have been calculated and the spectra obtained assigned. From this information the assignment of the C–O stretching frequencies of the parent molecule has been confirmed and the Cotton–Kraihanzel parameters refined. Further observations on the interpretation of intensities of the C–O stretching vibrations of Mn(CO)₅Br have also been discussed. Kinetic data also available from these experiments are presented and possible exchange mechanisms postulated.