MASS-SPECTROMETRIC STUDY OF [FE,C-3,H-6,O](-PHASE OXIDATION OF HYDROCARBONS BY (BARE) FEO+() ISOMERS RELEVANT IN THE GAS)

The structures and energetics of [Fe,C-3,H-6,O](+) isomers are probed by mass spectrometric means. The complexes Fe(CH3COCH3C+ Fe(CH3CH2CHO) (+), Fe(CH3OCH=CH2)(+), Fe(CH2O) (C2H4)(+), c-(FeOCH2CH2CH2)(+), Fe(CH 2=CH-CH2OH)(+), and Fe(OH)(C3H5)(+) can be distinguished by comparing their reactivity toward benzene and their collision-induced dissociati on mass spectra, respectively. These findings are used to interpret th e formation of [Fe,C-3,H-6,O](+) in oxidation reactions of hydrocarbon s by the highly reactive FeO+ cation. For example, in the reactions of FeO+ with norbornane and pentanol Fe(OH)(C3H5)(+) is produced, while the reaction of FeO+ with norbornane to yield [Fe,C-3,H6O](+) is one o f the rare cases of initial C-C bond activation by a ''bare'' transiti on-metal oxide. The reaction of FeO+ with propene involves formation o f metalla oxetanes as primary products. in general, ''bare'' FeO+ is n ot selective and allylic C-H bond activation of propene competes effic iently, thus pointing to a potentially rich chemistry.