Reaction of [(η5-C5H5)-M]+ (M = Mn, Fe, Co) with Dichloromethane in the Gas-Phase: C-C Bond Formation and Production of MCl2

Reactions of cyclopentadienylic transition metal ions with different substrates can be exploited to obtain C–C bond formation or C–H bond activation. To gain insight into the intrinsic features of these ligated metal ions in the gas phase, we recently reported on the reaction of (C5H5)-Fe+ with CH2Cl2 that disclosed an unusual iron transfer and C-C bond formation, giving protonated benzenium ions and FeCl2.Here we report on the activation of dicholoromethane by (C5H5)-M+ ions (M = Mn, Co) as an extension of our interest in cyclopentadienylic transition metal ions. The reactions have been studied in the gas phase at room temperature by mass spectrometry in the high pressure regime characteristic of ion trap experiments (ITMS). Results have been compared with those obtained for the (C5H5)-Fe+/CH2Cl2 system. The reactions lead to the same products, namely protonated benzenium ions and the corresponding metal chloride. Main differences are found in the cobalt system, which shows a higher formation of the addition ion [C5H5)-Co-CH2Cl2]+ that is not observed with manganese and only poorly with iron. The rate constant, efficiency and the branching ratio of all products of the reactions have been measured.