Competitive Ion-Molecule Reactions within V+(CH3COOCH3)n Clusters

We have investigated the competitive insertion reactions of V+ within V+(MeAc)n heteroclusters using a combination of laser ablation and supersonic beam expansion. The mass spectrum exhibited peaks corresponding to two types of reaction products: (a) V+-containing clusters (an, bn, cn, dn series) and (b) VO+-containing clusters (en, fn, tn series). The V+(OCH3)(MeAc)n and V+(CH3COO)(MeAc)n ions are attributed to the insertion of a V+ ion into the C=O bond of MeAc. The observation of the VO+(MeAc)n ion series is understood on the basis of a C=O insertion reaction followed by H atom transfer and CH2CHOCH3 elimination. In addition, sequential reactions of VO+ ions are also observed. Density functional theory calculations were performed to rationalize the reaction pathways and energetics of the proposed mechanism