MASS SPECTRA AND IONIZATION POTENTIALS OF C5H5MN(CO)2PX3 COMPLEXES

The mass spectra of complexes of the type C5H5Mn(CO)2PX3 (X = H, Cl, Br, C6H5, iso-C3H7, OC6H5, and iso-OC3H7) are reported and the fragmentation processes are discussed. The development of the fragmentation is initiated by the elimination of CO groups, but X radicals may also primarily be removed. The nature of the substituent X plays a decisive role in the various dissociation processes of the ion C5H5MnPX+3. If X is highly electronegative, for example, a rearrangement consisting of the migration of the X group to the central metal is preferred. With the elimination of MnX2, heterocyclic ions of the general formula C5H5PX+ among others are formed. Furthermore, correlations are observed between the mass spectroscopically measured ionization potentials of the complexes and the v(CO) force constants as well as the IP values of the free phosphine ligands. The measurements afford information about the donor-acceptor strengths of the PX3 molecules. © 1969.