Metal-assisted hydroformylation on a SiO sub 2 -attached Rh dimer. In situ EXAFS and FT-IR observations of the dynamic behaviors of the dimer site

Journal Article · Wed Dec 05 04:00:00 EST 1990 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00181a010· OSTI ID:5955451

Asakura, Kiyotaka; Kitamura-Bando, Kyoko; Iwasawa, Yasuhiro ^[1]; Arakawa, Hironori ^[2]; Isobe, Kiyoshi ^[3]

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1. Univ. of Tokyo (Japan)
2. National Chemical Lab. for Industry, Ibaraki (Japan)
3. Inst. for Molecular Science, Aichi (Japan)

trans-(Rh(C{sub 5}Me{sub 5})(CH{sub 3})){sub 2}({mu}-CH{sub 2}){sub 2} was supported on the SiO{sub 2} surface by the reaction with OH groups of SiO{sub 2} at 313 K, followed by evacuation at 373 K. In this attaching reaction, the Rh dimer complexes were bound to the SiO{sub 2} surface through Rh-O(surface) bonds, losing one CH{sub 3} ligand and one C{sub 5}Me{sub 5} ligand per Rh dimer. The attached Rh dimers were found to be more active and selective than a conventionally prepared Rh/SiO{sub 2} catalyst. The structure change of the Rh dimer sites in each reaction step for catalytic hydroformylation was followed by means of in-situ FT-IR and in situ EXAFS techniques. The Rh-Rh bond in the attached Rh dimers (Rh-Rh = 0.262 nm) was cleaved by CO adsorption to form monomer pairs (Rh(C{sub 2}H{sub 5})(CO){sub 2}(O-Si) + Rh(C{sub 5}Me{sub 5})(O-Si)). Heating the monomer pairs to 423 K under vacuum resulted in CO insertion, with new peaks exhibited at 1,710 and 1,394 cm{sup {minus}1} due to the acyl ligand.

• OSTI ID: 5955451
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 112:25; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACYLATION
ALKENES
CARBOXYLIC ACID SALTS
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
COMPLEXES
CYCLOALKENES
CYCLOPENTADIENE
DIENES
DIMERS
ETHYLENE
FORMATES
FOURIER TRANSFORM SPECTROMETERS
HYDROCARBONS
INFRARED SPECTRA
LIGANDS
MEASURING INSTRUMENTS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLYENES
REACTION INTERMEDIATES
RHODIUM COMPLEXES
SILICON COMPOUNDS
SILICON OXIDES
SPECTRA
SPECTROMETERS
TRANSITION ELEMENT COMPLEXES