Gas-phase reactions of M+ and MO+ (M = Sc, Ti, V) with toluene

The reactions of M+ and MO+ (M = Sc, Ti, V) with toluene in the gas phase have been characterized by employing Fourier transform mass spectrometry. Dehydrogenation is the main reaction channel for Sc+ and Ti+ in the reactions with toluene producing MC7H6+, but V+ is unable to dehydrogenate toluene and only forms an adduct product. To further characterize these reactions, C6H5CD3 and toluene-alpha-C-13 were also studied, and unexpectedly, different behavior was observed in their reactions with Sc+ compared with Ti+. In the reactions with C6H5CD3, SC+ predominantly eliminates HD (90%) and to a lesser extent H-2 (8%), and D-2 (2%), whereas Ti+ exhibits lesser specificity and eliminates HD (50%), H-2 (20%), and D-2 (30%). Ion/molecule reactions (IMR) of the three different product ions, TiC7H6-nDn+ (n = 1, 2, and 3) point to a common structure for all three. IMR of the products from the reactions with the C-13-labeled toluene provide evidence for a common structure but some differences in the reaction mechanisms for ScC7H6+ and TiC7H6+. Collision-induced dissociation (CID) and ligand exchange reactions provide evidence that the structure of MC7H6+ is CpM(CCH)(+). The reactions were very fast, proceeding at close to collision rates. MO+ were found to be unreactive with toluene and only formed the adducts MO(toluene)(+).