Heteronuclear Diatomic Transition-Metal Cluster Ions in Gas Phase. Reactions of CoFe(1+) with Hydrocarbons

Article abstract of DOI:10.1021/ja00292a021

Reactions of CoFe(1+) with several hydrocarbons in the gas phase by using Fourier transform mass spectrometry are described.No rection is observed between CoFe(1+) and cyclic (C3-C6) or acyclic (C1-C6) alkenes.CoFe(1+) reacts with aliphatic alkenes containing a linear C4 unit yielding predominantly dehydrogenation products.The only example where C-C bond cleavage is observed with aliphatic alkenes is for 3,3-dimethyl-1-butene wich is a special case since it does not have β-hydrogens available for elimination upon olefin coordination.In this case, insertion into an allylic C-C bond occurs followed by a β-hydride shift resulting in methane elimination.Collisional activation of CoFe(olefin)(1+) species containing a linear C5 or C6 chain undergoes facile dehydrcyclizations in analogy to what is observed on metal surfaces.Collisional activation of branched-olefin complexes indicates that skeletal isomerizations do not occour. Bis(cyclopentadienyl)CoFe(1+) ions undergo facile elimination of either Co or Fe forming ferrocene and cobaltocene ions, respectively.The corresponding bis(benzene)CoFe(1+) ions are much more stable with formation of Co(bezene)2(1+) and CoFe(benzene)(1+) formed in low efficiency upon collisional activataion.