TY - JOUR
T1 - Activation of metal-carbonyl clusters by their encapsulation within alumina sol-gel matrices
AU - Eliau, Nino
AU - Avnir, David
AU - Eisen, Moris S.
AU - Blum, Jochanan
N1 - Funding Information:
We gratefully acknowledge the financial support of this study from the Israel Science Foundation through Grant No. 177/03 and the Ministry of Science for support under the Tashtiot project.
PY - 2005/8
Y1 - 2005/8
N2 - Entrapment of Ru3(CO)12 and Os3(CO) 12 within alumina sol-gel matrices, (obtained by hydrolysis and polycondensation of a THF solution of aluminum isopropoxide) converts these clusters into highly active, leach-proof and recyclable hydrogen transfer catalysts. Likewise Rh2Co2(CO)12 which, in its silica sol-gel entrapped form, neither promotes the isomerization of allylbenzene nor the disproportionation of dihydroarenes, becomes upon its entrapment in an alumina sol-gel matrix, an efficient and recyclable catalyst for these reactions. While the entrapped osmium cluster promotes at 100-110°C and 20 bar only the hydrogenation of alkenes, the ruthenium analog catalyzes also the saturation of the aromatic C-C bonds. The hydrogenations take place via the hydride mechanism. XPS and TEM studies revealed that the carbonyl clusters do not decompose to give detectable amounts of (entrapped) metal particles during the encapsulation as well as during the catalytic processes.
AB - Entrapment of Ru3(CO)12 and Os3(CO) 12 within alumina sol-gel matrices, (obtained by hydrolysis and polycondensation of a THF solution of aluminum isopropoxide) converts these clusters into highly active, leach-proof and recyclable hydrogen transfer catalysts. Likewise Rh2Co2(CO)12 which, in its silica sol-gel entrapped form, neither promotes the isomerization of allylbenzene nor the disproportionation of dihydroarenes, becomes upon its entrapment in an alumina sol-gel matrix, an efficient and recyclable catalyst for these reactions. While the entrapped osmium cluster promotes at 100-110°C and 20 bar only the hydrogenation of alkenes, the ruthenium analog catalyzes also the saturation of the aromatic C-C bonds. The hydrogenations take place via the hydride mechanism. XPS and TEM studies revealed that the carbonyl clusters do not decompose to give detectable amounts of (entrapped) metal particles during the encapsulation as well as during the catalytic processes.
KW - Catalysis
KW - Doped alumina sol-gel
KW - Hydrogen-transfer reactions
KW - Metal carbonyls
UR - http://www.scopus.com/inward/record.url?scp=23844545554&partnerID=8YFLogxK
U2 - 10.1007/s10971-005-1403-4
DO - 10.1007/s10971-005-1403-4
M3 - 文章
AN - SCOPUS:23844545554
SN - 0928-0707
VL - 35
SP - 159
EP - 167
JO - Journal of Sol-Gel Science and Technology
JF - Journal of Sol-Gel Science and Technology
IS - 2
ER -