DFT studies for dehydrogenation of methane by gas-phase Ru+

The dehydrogenation reaction of Ru+ toward methane has been investigated theoretically. All structures on the potential surface are optimized at the density functional theory (DFT) level, using the empirically parametrized hybrid functional B3LYP. Relative energies are calculated both at the B3LYP level, using large basis sets RECP + 6-311+G**. The minimum energy pathway may proceed as 4 Ru + + CH 4 → 4 RuCH 4 + → 4 TS 1 → 4 RuH ( CH 3 ) + → 2 TS 2 → 2 RuH 2 ( CH 2 ) + → 2 TS 3 → 2 Ru ( CH 2 ) ( H 2 ) + → 2 RuCH 2 + + H 2 . The results indicate that there is no barrier in excess of the endothermicity of the H2 elimination reaction. The results for Ru+ are compared with those for the first- and third-row metal congeners and the differences in mechanism and behavior are discussed.