THE ADDITION OF HALOGENOCARBONS TO ALKENES IN THE PRESENCE OF [MO2(CO)4(ETA-C5H5)2], [MO2(CO)4(ETA-C5ME5)], [MO2(CO)6(ETA-C5H5)2] AND [(MO(CO)3(ETA-C5H4))2CH2]

The addition of halogenocarbons to alkenes in the presence of [Mo2(CO)4(η-C5Me5)2] (I) has been the subject of a detailed kinetic study. These results, together with the results of cross-over addition reactions of a halogenocarbon mixture and cross-over studies on catalyst mixtures of (I) and [Mo2(CO)4(η-C5H5)2] (IV) are interpreted in favour of a mechanism involving catalysis by an intact binuclear complex, but which also involves free radical intermediates. Studies on catalysis by [Mo2(CO)6(η-C5H5)2] (II) additional to those we reported earlier, suggest an analogous mechanism in this case, but also involving CO dissociation from the hexacarbonyl yielding IV as the active catalyst. A preliminary study of catalysis by [{Mo(CO)3(η-C5H4)}2CH2] (III) suggests this complex also follows a similar mechanism. © 1990.