Birgit Drießen-Hölscher

Selective two-phase-hydrogenation of sorbic acid with novel water soluble ruthenium complexes

Abstract Neutral and cationic water soluble Cp*-ruthenium-complexes of the type [Cp*Ru(CO)Cl(PR3)] and [Cp*Ru(CO)(PR3)]CF3SO3 (R=CH2OH, (CH2)3OH, Ph-m-SO3Na) have been synthesized for the first time and have been used as catalysts in two-phase-hydrogenations. The neutral complexes have been fully characterized. But the cationic complexes which have not been isolated are effective catalysts for the selective hydrogenation of sorbic acid in water/n-heptane leading to the formation of cis-3-hexenoic acid and trans-3-hexenoic acid.

Perfluorinated polyethers for the immobilisation of homogeneous nickel catalysts

Abstract The perfluorinated polyether Hostinert 216® is used as catalyst phase in a biphasic oligomerisation of ethene using a nickel catalyst with adapted designed ligand. The synthesis of the catalyst from hexafluoropropenoxide and Ni(COD) 2 is described. The catalytic results show the usefulness of fluorinated solvents for the immobilisation of homogeneous catalysts.

Halogenated oxo- and peroxotitanium porphyrinates as sensitizers for the photooxygenation of olefinic compounds

A series of porphines, oxotitanium(IV) and peroxotitanium(IV) porphyrinates were tested as photosensitizers of the singlet oxygen ene reaction with cyclohexene and cis-cyclooctene. The relative order of activity is: H2(P)>OTi(P)≥Ti(O2)P. Best stability is obtained for porphines or porphyrinate complexes with fluorine substituents. Oxotitanium(IV) porphyrinates are active in the decomposition of allylic hydroperoxides. The (photo)catalytic epoxidation occurs less readily than the thermal reaction at 82°C. Attempts of photocatalytic hydrogen peroxide activations lead to fast destruction of OTi(P).

Stereoselective catalytic hydrogenation of sorbic acid and sorbic alcohol with new Cp*Ru complexes

The new Cp*Ru complexes [Cp*Ru(η4-MeCHCHCHCHCO2H)]+ X− (X− = CF3SO3− or [B{C6H3(CF3)2-3,5} 4]−) are very effective catalysts for the hydrogenation of sorbic acid to cis-hex-3-enoic acid and of sorbic alcohol to cis-hex-3-en-1-ol (leaf alcohol) under mild conditions in liquid two-phase systems.