Reactivities of 2,6-dimethoxyphenyl methyl sulfide, selenide and telluridewith their onium salts

2,6-Dimethoxyphenyl derivatives of sulfur, selenium and tellurium, such as Me PhiE, Et PhiE, [Me(2)PhiE]X, [MeEt PhiE]X (Phi = 2,6-(MeO)(2)C6H3; E = S , Se, Te; X = MeSO4, ClO4, or PF6} have been prepared, mostly as crystals. The reaction rates and the equilibrium constants for methyl abstraction by Me PhiE from [MeR PhiE']ClO4 {R = Me, Et, Phi; E, E' = S, Se, Te) were meas ured by means of H-1 NMR spectra. Some representative results include: (1) R PhiE (R = Me, Phi; E = S, Se) react commonly with [MeR PhiE](+) (R = Me, Et, Phi; E = S, Se) to give the equilibrium mixture, except that Me PhiS do es not react with [MeEt PhiS](+); (2) R PhiE (R = Me, Phi; E = S, Se) do no t react with [MeR Phi Te](+) (R = Me, Et, Phi); (3) R Phi Te (R = Me, Phi) react with [MeR PhiE](+) (R = Me, Et, Phi; E = S, Se, Te) to complete the m ethyl abstraction (E = S, Se) or to give the equilibrium mixture (E Te); (4 ) the reaction rate of Me PhiE with [MeR PhiE](+). (R = Me, Et, Phi) increa ses in the orders E = S < Se < Te and E' S similar to Te < Se; (5) reaction s of [Me-2<Phi>E](+) are faster than those of [MeEt PhiE](+), which react f aster than [Me Phi E-2](+); (6) Me-E bond strength of [Me Phi E-2](+) incre ases in the order E = S less than or equal to Se < Te, but those of [Me-2<P hi>E](+) and [MeEt PhiE](+) increase in the order E = Se less than or equal to S < Te; (7) Me-E bond strength of [MeR<Phi>E](+) (E = S, Se) increases in the order R = Phi < Me < Et or Me < <Phi> < Et, while Me-Te bond strengt h of [MeR<Phi>Te](+) increases in the order R = Phi < Et < Me.