Experimental and theoretical studies toward a characterization of conceivable intermediates involved in the gas-phase oxidation of methane by bare FeO+. Generation of four distinguishable (Fe,C,H4,O)+ isomers

The application of collisional activation mass spectrometry (MS) on the (Fe,C,H4,O)+ potential energy surface readily identified the presence of CH4.FeO+, CH3-Fe-OH+, CH3O(H)Fe+ and CH2=Fe-OH2+ isomers in the gas phase. The four isomers were prepared from different ion/molecule gas phase reactions. In addition, attempts to prepare the insertion products H3CO-Fe-H+ and H-Fe-CH2OH+ failed possibly due to the complex potential energy surfaces involved in their formation. Moreover, the results from the ab initio molecular orbital calculations of the four isomers using MP2/ECP-DZ level of theory correlated with the MS analysis.