Activation of C-H and C-C Bonds in Alkanes by Heterodinuclear Metal Cluster Ions in the Gas Phase

Abstract

The reactivity of RhFe+, RhCo+, and LaFe+ with alkanes and oxygen contg. compds. was reported. These 3 clusters are the first heterodinuclear transition metal cluster ions obsd. to activate C-H and C-C bonds in alkanes. All 3 cluster ions react with alkanes larger than methane mainly via dehydrogenation. In this respect, the reactivity of RhFe+, RhCo+, and LaFe+ is more like that of Rh+ and La+ than that of Fe+ and Co+. RhFe+ and RhCo+ show similar patterns of reactivity with multiple dehydrogenation of alkanes larger than ethane, while LaFe+ shows less extensive dehydrogenation. Pentane and cyclopentane react with RhFe+ and RhCo+ to split the cluster and form RhC5H6+ and RhC5H5+, presumably the cyclopentadiene- and cyclopentadienylrhodium cations. The reactivity is discussed in terms of reduced overlap in cluster ions contg. a second or third row metal bound to a first row metal relative to clusters contg. two first row metals. Finally, oxide abstraction is obsd. for reaction of the clusters with ethylene oxide suggesting D°(MM'+-O) > 89 kcal/mol. [on SciFinder(R)]