Mechanistic Aspects of the Holmium-Mediated, Reciprocal Hydrogen/Sulfur Exchange in the Gas Phase: C6H5CH3+CH2S→C6H5CHS+CH4.

The thermal reaction of [Ho(CH₂S)]⁺ with toluene giving rise to [C₆H₅CHSHo]⁺ and CH₄ has been investigated using Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry complemented by density functional theory (DFT) calculations. The high reactivity of [Ho(CH₂S)]⁺ which is in distinct contrast with the non-reactivity of 'bare' Ho⁺ has its origin in the presence of a carbon-centered radical; the latter initiates hydrogen-atom abstraction from the methyl group of toluene as the first step of a sequence of hydrogen and sulfur transfer mediated by cationic holmium. [ABSTRACT FROM AUTHOR]