DEHYDRATION REACTIONS OF METAL-CATIONS (FE+ AND LAO+) WITH METHANOL CLUSTERS

Reaction of laser-generated metal cations (Fe+ and LaO+) with methanol clusters was studied in a molecular beam. The reaction products were analyzed by a time-of-flight mass spectrometer. A general reaction pattern is that of the methanol-methanol reaction which produces ether and water and which is induced by collision with the metal cations. However, very different reaction behaviors were found for Fe+ and LaO+. For Fe+, there was a critical size (n greater than or equal to 12) for the reaction of methanol clusters (CH3OH)(n), with ether loss and H2O retention. On the other hand, for LaO+, this critical size was 2, and the result was H2O loss and ether retention. Multiple-ether formation was identified in a narrow cluster size region with the number of MeOHs ranging from 2 to 4. Furthermore, the series corresponding to LaO+(MeOH)(n) or LaO+(Me(2)O)(MeOH)(n-2)(H2O) suddenly appeared for n greater than or equal to 12. The two different reaction patterns are discussed in terms of electrostatic and covalent effects in the presence and absence of a solvation shell, respectively.