Reactions of Lanthanide Cations with Methanol Clusters

Abstract

Reactions between lanthanide cations (from La+ to Lu+ except Pm+) and methanol clusters were studied in a pick-up source, and the product ions were analyzed using a reflectron time-of-flight mass spectrometer (RTOFMS). Those reactive ions including La+, Ce+, Pr+, Nd+, Gd+, Tb+, Ho+, Er+, and Lu+ react with methanol molecules forming dehydrogenation products LnCH2O+ and LnCH3O+. For large clusters, the dehydrogenation products become Ln(OCH3)2(CH3OH)n-2+. On the contrary, the relatively unreactive lanthanide ions including Sm+, Eu+, Dy+, Tm+, and Yb+ do not react with the methanol molecules. Only when they are solvated by a sufficient number of methanol molecules does dehydrogenation occur and yield Ln(OCH3)2+(CH3OH)n-2 (LnOCH3+(CH3OH)n-1 for Eu+). The relative reactivities of these ions are discussed in terms of their electronic configurations. Reactions of LnO+ with methanol clusters lead to water elimination and produce LnO2C2H6(CH3OH)n-2+. As cluster size increases to n ≈ 13, the reaction is quenched, and only the association products LnO(CH3OH)n+ are formed.