Tuning the Reactivities of the Heteronuclear [Aln V3-n O7-n ]+ (n=1, 2) Cluster Oxides towards Methane by Varying the Composition of the Metal Centers.

The thermal gas-phase reactions of [Al2 VO5 ]+ and [AlV2 O6 ]+ with methane have been explored by using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry complemented by high-level quantum chemical calculations. Both cluster ions chemisorbed methane as the major reaction channels at room temperature. [Al2 VO5 ]+ could break only one C-H bond to liberate CH3 , whereas [AlV2 O6 ]+ exhibited higher oxidizing ability such that it brings about the selective generation of formaldehyde. Mechanistic aspects are revealed and the crucial roles of the metal centers are discussed.