Silica-Supported Cyclopentadienyl-Rhodium(I),-Cobalt(I), and-Titanium(IV) Complexes

Article abstract of DOI:10.1016/0022-328X(86)80433-8

The silylated cyclopentadiene derivative, (MeO)3Si(CH2)3C5H5, synthesised from commercially-available (MeO)3Si(CH2)3Cl, has been used to prepare the complexes <η⁵-(MeO)3Si(CH2)3C5H4>Rh(CO)2, <η⁵(MeO)3Si(CH2)3C5H4>Rh(COD)(COD= cyclo-octa-1,5-diene), and <η⁵-(MeO)3Si(CH2)3C5H4>2TiCl2.The complexes <η⁵(MeO)3Si(CH2)3C5H4>TiCl3, prepared by reaction of NaC5H4(CH2)3Si(OMe)3 with TiCl4 (1/1 molar ratio) and also by reaction of <η⁵-(MeO)3Si(CH2)3C5H4>Ti(OEt)3 with CH3COCl, proved to be very unstable.Attempts to synthesise the complex <η⁵-(MeO)3Si(CH2)3C5H4>(η⁵-C5H5)TiCl2, either by reaction of <η⁵-(MeO)3Si(CH2)3C5H4>TiCl3 with NaC5H4 or reaction of (η⁵-C5H5)TiCl3 with NaC5H4(CH2)3Si(OMe)3, gave none of the expected product and only (η⁵-C5H5)TiCl2 could be isolated from these reactions.The cyclo-octadiene rhodium complex supported on silica has been shown to be an efficient cyclotrimerization catalyst, and the silica-supported titanium complex SIL-(CH2)3C5H4)TiCl2 is, after reduction with butyllithium, an efficient and selective catalyst for the hydrogenation of alk-1-enes.