ANCHORING RHODIUM(I) ON BENZOYLTHIOUREA-FUNCTIONALIZED SILICA XEROGELS - PRODUCTION OF RECYCLABLE HYDROFORMYLATION CATALYSTS AND THE CRYSTAL-STRUCTURE OF THE MODEL-COMPOUND [RH(COD)(HBZTU)CL]
D. Cauzzi et al., ANCHORING RHODIUM(I) ON BENZOYLTHIOUREA-FUNCTIONALIZED SILICA XEROGELS - PRODUCTION OF RECYCLABLE HYDROFORMYLATION CATALYSTS AND THE CRYSTAL-STRUCTURE OF THE MODEL-COMPOUND [RH(COD)(HBZTU)CL], Journal of organometallic chemistry, 488(1-2), 1995, pp. 115-125
Two benzoylthiourea-functionalized silica xerogels, 4.5SiO(2).SiO3/2(C
H2)(3)NHC(S)NHC(O)Ph (XGbztu) and SiO3/2 (CH2)(3)NHC(S)NHC(O)Ph (XGbzt
u) have been prepared from (EtO)(3)Si(CH2)(3)NHC(S)NHC(O)Ph by the so
l-gel process. They are able to bind rhodium(I) species giving the com
posite materials Rh/XGbztu and Rh/XGbztu, which are very active insol
uble and recoverable catalysts for the hydroformylation of styrene. Th
e anchored species undergo major changes during the catalytic cycles,
particularly in the Rh/XGbztu system, whose iso/normal selectivity rat
io gradually increased in the first five runs. Furthermore, CH3(CH2)(2
)NHC(S)NHC(O)Ph (HBztu) has been studied as a model of the surface bin
ding function. The structure of [Rh(cod)(Hbztu)Cl](1), which represent
s a suitable molecular model for the anchored complexes, has been dete
rmined by X-ray diffraction.