| Abstrakt: |
The ruthenium (II) diene complexes [Ru(X)(Cl)(nbd)(dppb)] (X = Cl, H; nbd = 2,5‐norbornadiene; dppb = PPh2(CH2)4PPh2) have been prepared and characterized spectroscopically. The X‐ray crystal structure of RuCl2(nbd)(dppb) (crystal data at 22°C: space group P1, a= 10.896 (1) Å, b= 15.168(2) Å, c= 10.829 (1) Å, α = 103.02(1)°, β = 107.08(1)°, γ = 81.65(1)°, Z= 2, R= 0.054 for 6420 reflections) shows an octahedral geometry at Ru, with the chloro ligands slightly distorted from a transconfiguration (Cl)(1)‐Ru‐C1(2) = 168.4°); the unit cell contains two molecules of the complex and one molecule of benzene. Reaction of this complex with H2, in presence of Proton Sponge (PS, 1,8‐bis(dimethylamino)naphthalene) as base, is complicated by initial dissociation of nbd, and [Ru2Cl5(dppb)2]−‐PSH+is the major product. A minor product, the hydrido(diene) complex trans‐RuCl(nbd)(dppb) 5, characterized spectroscopically, is more effectively synthesized from (a) trans‐Ru(H)Cl(nbd)(PPh3)2, 1, and dppb, or (b) reaction of RuCl2(dppb)‐(PPh3) with H2in presence of nbd and PS. Complex 5is unreactive toward H2or CO while 1has been shown previously to give η2‐H2and norbornenoyl derivatives, respectively; the differences in reactivity are discussed. |
Plný text