Photoactivation of cluster catalysis: a comparison of 1-pentene isomerization by tetracarbonyl(triphenylphosphine)ruthenium and 1,1,1,2,2,2,3,3,3- nonacarbonyl-1,2,3-tris(triphenylphosphine)-triangulo-triruthenium. Technical report

Technical Report · Wed Nov 29 04:00:00 EST 1978

OSTI ID:6227458

Graff, J L; Sanner, R D; Wrighton, M S

The photocatalyzed isomerization of 1-pentene to trans- and cis-2-pentene by Ru(CO)4PPh3 and Ru3(CO)9(PPh3)3 is reported along with data for Ru3(CO)12, Fe3(CO)12, and Fe(CO)5. The primary photoprocess in Ru(CO)4PPh3 is dissociative loss of CO giving a coordinatively unsaturated species having the same empirical formula Ru3(CO)9(PPh3)3; the trinuclear species undergoes Ru-Ru bond rupture and ultimate declusterification subsequent to photo-excitation giving a quantitative yield of Ru(CO)4PPh3 under CO or Ru(CO)3(PPh3)2 in the presence of PPh3. The crucial result is that the cluster yields a different catalytically active species compared to Ru(CO)4PPh3, since the initial ratio of trans- and cis-2-pentene is different for the two photocatalysts. The photocatalysis and primary photoprocesses suggest that the isomerization from the Ru3(CO)9(PPh3)3 results from an active form of the cluster. By way of contrast, Fe(CO)5 and Fe3(CO)12 yields the same initial ratio of photocatalytic products, implicating a common, mononuclear catalytic species. Since the clusters are good visible absorbers compared to the mononuclear species, photoactivation of cluster catalysis can be effected with low energy visible light.

• Research Organization: Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Chemistry
• OSTI ID: 6227458
• Report Number(s): AD-A-061871
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ALKENES
CARBONYLS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COMPLEXES
HYDROCARBONS
ISOMERIZATION
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PENTENES
PHOTOCHEMICAL REACTIONS
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES