Solution and solid-gas reactivity of unsaturated [RuCp(tmeda)+ (tmeda = Me2NC2H4NMe2)

The coordinatively unsaturated complex [RuCp(tmeda)](+) has been prepared by the reaction of [RuCp(tmeda)Cl] with NaBAr4' (Ar' = 3,5-C6H3(CF3)(2)) in fluorobenzene. The PF6- salt of [RuCp(tmeda)](+) is prepared by heating [RuCp(tmeda)(CH3CN)]PF6 at 150 degrees C under reduced pressure (10(-2) atm). The X-ray crystal structure of [RuCp(tmeda)](+) as the BAr4', salt has been determined showing the absence of any agostic interactions between ruthenium and the C-H bonds of the diamine ligand, and only minor deviations from the planar geometry at Ru. [RuCp(tmeda)](+) reacts readily with the gases H-2, CH2=CH2, CHF=CH2, HC=CH, CO, HCl, N-2, and O-2 at low temperature to give [RuCp(tmeda)(eta(2)-H-2)](+), [RuCp(tmeda)(eta(2)-CH2=CH2)](+), [RuCp(tmeda)(eta(2)-CHF=CH2)](+), [RuCp(tmeda)(eta(2)-HC=CH)](+), [RuCp(tmeda)(CO)](+), [RuCp(tmeda)(H)(Cl)](+), [RuCp(tmeda)(N-2)](+), and [RuCp(tmeda)(O-2)](+). The reactions of [RuCp(tmeda)][BAr4'] with the above gases have also been carried out as solid-gas reactions. Treatment of [RuCp(tmeda)](+) with the terminal acetylenes HC=CR (R = Bu-t, SiMe3) results in the formation of the vinylidene complexes [RuCp(tmeda)(=C=CHR)](+). In the case of R=SiMe3 upon treatment with HCl, the parent vinylidene complex [RuCp(tmeda)(=C=CH2)](+) is formed. [RuCp(tmeda)(eta(2)-HC=CH)](+) and [RuCp(tmeda)(=C=CH2)](+) are not interconvertable for kinetic reasons. Furthermore, [RuCp(tmeda)](+) reacts slowly with both CH2Cl2 and CH2Br2 to give the carbene complex [RuCp(tmeda)(=CH2)](+) involving double C-X bond activation. (C) 2000 Elsevier Science S.A, All rights reserved.