ROOM-TEMPERATURE REACTIONS OF THE INTERMEDIATE(S) GENERATED BY FLASH-PHOTOLYSIS OF (ETA(5)-C5H5)FE(CO)(2)CH3

The transient formed by the photolysis of the methyl complex CpFe(CO)( 2)CH3 (M, Cp = (eta(5)-C5H5)) has been studied by FTIR spectroscopy in methylcyclohexane solution at 77 K and by time-resolved infrared dete ction in ambient-temperature solutions in cyclohexane and tetrahydrofu ran. The transient IR spectrum of the intermediate I-M displays a sing le nu(co) absorption band and can be characterized as a monocarbonyl. In 295 K solution, the reaction of I-M with CO occurs with second-orde r kinetics (rate = k(co)[I-M][CO]) with k(co) values of(6.3 +/- 0.2) x 10(8) and (3.4 +/- 0.4) x 10(6) M-1 s(-1) in cyclohexane and THF, res pectively. On the basis of these data, I-M is concluded to be the solv ento complex CpFe(CO)(Sol)CH3.