Chemistry and catalytic properties of ruthenium and osmium complexes. 3. Development of highly active systems for the homogeneous hydrogenation of aldehydes and ketones
The catalytic hydrogenation of aldehydes and ketones to yield the corresponding alcohols exclusively is efficiently achieved by use of a series of 19 ruthenium and 4 osmium complexes containing hydride, phosphine, and carboxylate ligands, under moderate reaction conditions. For complexes MHX(CO)(PR/sub 3/)/sub 3/ the catalytic activity is dependent on X (halide) and independent of R. Evidence is presented for a mechanism involving MHX(CO)(PR/sub 3/)/sub 2/ as the active species and alkoxy-metal intermediates in the cycle. Carboxylate species MX(OCOR)(CO)(PPh/sub 3/)/sub 2/ show a catalytic behavior dependent on the stereochemistry of the complex, on X, and on the electronic nature of the R group. Correlations between k/sub obsd/ for the catalytic reaction and pK/sub a/ of the acid from which carboxylate ligands are derived have been found. This is explained in terms of a mechanism involving a bidentate-monodentate equilibrium for the carboxylate as a key step in the catalysis.
- Research Organization:
- Instituto Venezolano de Investigaciones Cientificas, Caracas
- OSTI ID:
- 5741743
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 25:8; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALDEHYDES
AROMATICS
CARBONYLS
CATALYSIS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COMPLEXES
DATA
EXPERIMENTAL DATA
HYDROGENATION
INFORMATION
KETONES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OSMIUM COMPLEXES
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES