Protonation and protolysis of [Fe4(CO)12(CCH3)]−

Abstract The reaction of [Fe 4 (CO) 12 (CCH 3 )] − with HSO 3 CF 3 in CH 2 Cl 2 solution yields the compound HFe 4 (CO) 12 (CCH 3 ), which was characterized chemically, spectroscopically and by single crystal X-ray diffraction. This compound retains the approximately tetrahedral 4-iron framework characteristic of the parent anion and protonation appears to have occurred on an FeFe bond. In neat HSO 3 CF 3 , infrared and NMR spectroscopic evidence indicates that another proton adds to the metal framework producing [H 2 Fe 4 (CO) 12 (CCH 3 ] + . On long standing, this solution evolves CO, and H 2 , and small amounts of CH 4 and C 2 H 6 . On the time scale of the experiments described here the latter two gases are obtained in an approximately 1 3 ratio. Deuterated acid leads to mixtures of the various isotopomers of CH 4 but the ethane is CD 3 CH 3 . Possible mechanisms for hydrocarbon production are discussed.