SOLVATION OF TRANSITION-METAL ION COMPLEXES IN THE GAS-PHASE

Solvation of the gas-phase transition-metal d0 complexes ScO+, YO+, YCHCN+ and NbO2+ with some protic and aprotic solvents has been studied using Fourier-transform ion cyclotron resonance mass spectrometry. The relative rate constants for formation of the solvated oxides show strong non-monotonic fluctuations with increasing extent of solvation. For ScO+ and YO+ the third solvent molecule attaches more rapidly than the second, while for NbO2+ the second attaches more rapidly than the first. This behavior suggests that in spite of the formal do character of the metal centers in these systems, simple electrostatic binding is not occurring. In contrast, YCHCN+ shows a continuous decrease in the rate for solvation with up to three molecules of CH3CN. The effects of solvation on the subsequent reactions of the metal oxides has been studied. YO+ solvation (with up to three H2O or two NH3 Molecules) does not affect its arene C-H bond activation reactions. However, solvation of ScO+ and NbO2+ with one or two NH3 or H2O molecules shuts off benzene dehydrogenation.