A 14-electron ruthenium(II) hydride, [RuH(CO)(P(t)BU2Me)(2)]BAr '(4) (Ar '=3,5-(C6H3)(CF3)(2)): Synthesis, structure, and reactivity toward alkenes and oxygen ligands

Triflate in RuH(OTf)(CO)L-2 (L = (PBu2Me)-Bu-t) can be abstracted by NaBAr' (4) (Ar' = C6H3-(CF3)(2)) in C6H5F to give 14-electron RuH(CO)L-2(+), which has agostic donation by one Bu-t methyl group from each phosphine. This ca tion binds CH2Cl2 in an eta(2) fashion, and it binds OEt2 and HaO in the si te trans to CO. It binds:ethylene trans to hydride, and additional ethylene is catalytically dimerized to cis- and trans-but-2-ene at -30 degrees C in wC(6)H(5)F/toluene; this dimerization is slower in CH2Cl2 solvent. Propyle ne and H2C=CHF also bind to RuH(CO)L-2(+) trans to hydride, and the latter is converted to ethylene and Ru/F products. Vinyl ethers seem to bind eta(1 ) via ether oxygen more than eta(2) via the CC bond, and trans to CO, and t his species then isomerizes to the RuL2(CO)(eta(2)-CH2CH2OR) insertion prod uct at -60 degrees C. In contrast, 2,3-dihydrofuran gives a cyclic oxygen-s tabilized carbene complex. A discussion of the results based on DFT (B3PW91 ) calculations is presented in the following paper.