RESUMO
A ruthenium hydride with a bulky tetra-substituted Cp ligand, (Cp(i)(Pr(4)))Ru(CO)(2)H (Cp(i)(Pr(4)) = C(5)(i-C(3)H(7))(4)H) was prepared from the reaction of Ru(3)(CO)(12) with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (Cp(i)(Pr(4)))Ru(CO)(2)H was determined by X-ray crystallography. The ruthenium hydride complex (C(5)Bz(5))Ru(CO)(2)H (Bz = CH(2)Ph) was similarly prepared. The Ru-Ru bonded dimer, [(1,2,3-trimethylindenyl)Ru(CO)(2)](2), was produced from the reaction of 1,2,3-trimethylindene with Ru(3)(CO)(12), and protonation of this dimer with HOTf gives {[(1,2,3-trimethylindenyl)Ru(CO)(2)](2)-(mu-H)}(+)OTf (-). A series of ruthenium hydride complexes CpRu(CO)(L)H [L = P(OPh)(3), PCy(3), PMe(3), P(p-C(6)H(4)F)(3)] were prepared by reaction of Cp(CO)(2)RuH with added L. Protonation of (Cp(i)(Pr(4)))Ru(CO)(2)H, Cp*Ru(CO)(2)H, or CpRu(CO)[P-(OPh)(3)]H by HOTf at -80 degrees C led to equilibria with the cationic dihydrogen complexes, but H(2) was released at higher temperatures. Protonation of CpRu[P(OPh)(3)](2)H with HOTf gave an observable dihydrogen complex, {CpRu[P-(OPh)(3)](2)(eta(2)-H(2))}(+)OTf (-) that was converted at -20 degrees C to the dihydride complex {CpRu[P(OPh)(3)](2)(H)(2)}(+)OTf (-). These Ru complexes serve as catalyst precursors for the catalytic deoxygenation of 1,2-propanediol to give n-propanol. The catalytic reactions were carried out in sulfolane solvent with added HOTf under H(2) (750 psi) at 110 degrees C.
Assuntos
Complexos de Coordenação/química , Fosfinas/química , Propilenoglicol/química , Compostos de Rutênio/química , Catálise , Complexos de Coordenação/síntese química , Cristalografia por Raios X , Ligantes , Modelos Moleculares , Fosfinas/síntese química , Compostos de Rutênio/síntese químicaRESUMO
Et2C=O is hydrogenated under solvent-free conditions using a catalyst prepared by hydride abstraction from HMo(CO)2[eta5:eta1-C5H4(CH2)(2)PCy2]; the catalyst functions at low catalyst loadings (< 0.4 mol%).
RESUMO
The internal OH group of 1,2-propanediol is selectively removed in the deoxygenation catalyzed by [{Cp*Ru(CO)2 }2 (µ-H)]+ OTf- (1, Cp*=C3 Me5 , OTf=trifluoromethanesulfonate; see scheme). This reaction provides a model for deoxygenation of polyols derived from carbohydrates, for use in alternative, biomass-based feedstock applications. An ionic mechanism is proposed that involves the dihydrogen complex [Cp*Ru(CO)2 (η2 -H2 )]+ .
