GAS-PHASE CHEMISTRY OF METHENYLTRICOBALT NONACARBONYL RADICAL-ANIONS

The gas-phase chemistry of the radical anions of methenyltricobalt non acarbonyls, YCCo3(CO)(9), where Y is H, CH3, C6H5, C6H4F, CO2CH3, F, a nd Cl, is reported. Molecular anions are not stable, and YCCo3(CO)(n) fragments are formed by losses of carbon monoxide via dissociative ele ctron capture. The fragmentation that occurs upon ionization (seen in full-scan mass spectra) or collisional activation (seen in tandem mass spectra) is minor and is in accord with the proposed electron-rich, d elocalized core of the YCCo3 moiety. Bimolecular reactions of the meth enyltricobalt nonacarbonyl radical anions with their neutral precursor or with neutral ligands were studied by Fourier transform mass spectr ometry(FTMS). The reactions with the neutral precursors result in high er-order clusters containing five or six cobalt atoms and both apical substituents (i.e., [(YC)(2)Co-5(CO)(11)](-) Or [(YC)(2)Co-6(CO)(13)]( -)) In mixtures of the methenyltricobalt nonacarbonyls with neutral li gands, substitution reactions are observed in which carbon monoxide is replaced by pi-bonding ligands but not sigma-bonding ligands.