ORGANOMETALLIC COMPOUNDS OF THE LANTHANIDES - CXXIII - LANTHANIDE BENT-SANDWICH COMPLEXES WITH THE BULKY TETRAMETHYL-ISO-PROPYLCYCLOPENTADIENYL LIGAND - SYNTHESIS, STRUCTURES AND CATALYTIC ACTIVITY FOR THE HYDROSILYLATION OF ALKENES ALKYNES/

The trichlorides of yttrium, samarium and lutetium react with two equi valents of Na[(C5Me4Pr)-Pr-i] in THF to form [(eta(5)-(C5Me4Pr)-Pr-i)( 2)LnCl(THF)] (Ln = Y (1), Sm (2), Lu (3)). Metathesis of 1-3 with LICH , in diethyl ether and LiCH(SiMe3)(2) in toluene gives [(eta(5)-(C5Me4 Pr)-Pr-i)(2)LnCH(3)(THF)] (Ln = Y (4), Lu (5)) and [(eta(5)-(C5Me4Pr)- Pr-i)(2)Ln{CH(SiMe3)(2)}] (Ln = Y (6), Sm (7)), respectively. The 1:2 reaction of LnI2(THF)x (Ln = Sm, Yb) with Na[(C5Me4Pr)-Pr-i] in THF re sults in the formation of the divalent metallocenes [(eta(5)-(C5Me4Pr) -Pr-i)(2)Ln(THF)] (Ln = Sm (8), Yb (9)). The new compounds with the bu lky tetramethyl-iso-propylcyclopentadienyl ligands were characterized by C, H analysis, mass spectrometry and NMR spectroscopy. Additionally , single crystal X-ray structure determination of the lutetium complex es 3 and 5 was performed. It has been shown that the alkyl complexes 4 -7 are effective precatalysts for the hydrosilylation of alkenes and a lkynes. The results of the described investigations are discussed. (C) 1998 Elsevier Science S.A. All rights reserved.