Synthesis of Ruthenium Carbonyl Complexes with Phosphine or Substituted Cp Ligands, and Their Activity in the Catalytic Deoxygenation of 1,2-Propanediol

摘要

A ruthenium hydride with a bulky tetra-substituted Cp ligand, (Cp-iPr4)RU(CO)(2)H (Cp-iPr4 = C-5(i-C3H7)(4)H was prepared from the reaction of RU3(CO)(12) with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (Cp-iPr4)RU(CO)(2)H was determined by X-ray crystallography. The ruthenium hydride complex (C(5)Bz(5))RU(CO)(2)H (Bz = CH2Ph) 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), PCy3, PMe3, P(p-C6H4F)(3)] were prepared by reaction of Cp(CO)(2)RuH with added L. Protonation of (Cp-iPr4)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 dihydrde 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 carded out in sulfolane solvent with added HOTf under H-2 (750 psi) at 110 degrees C.