PENTAMETHYLCYCLOPENTADIENYL DICARBOLLIDE DERIVATIVES OF SCANDIUM

The reactions Of [CP*SCCl2]x (CP* = (eta5-C5Me5)) with Na2[C2B9H11] or [Cp*ScMe2]x With C2B9H13, followed by treatment with THF yield CP*(C2B9H11)Sc(THF)3. Alkylation of Cp*-(C2B9H11)Sc(THF)3 with LiCH(SiMe3)2 yields Cp*(C2B9H11)ScCH(SiMe3)2Li(THF)3, and {[CP*(C2B9H11)ScCH(SiMe3)2]2Li}.Li(THF)3, which is obtained by its recrystallization from pentane/toluene, has been characterized structurally. This alkyl derivative reacts slowly with H-2 to yield [CP*(C2B9H11)ScH]2[Li(THF)n]2, a surprisingly unreactive scandium hydride dimer. Once again, recrystallization from toluene affords a crystalline form with less coordinated THF, [CP*(C2B9H11)ScH]2[Li(THF)2.3/2(C6H5CH3), Whose structure reveals that the two anionic [CP*(C2B9H11)ScH]- fragments are held together by reciprocal B-H dative bonding from the dicarbollide ligand to the electron deficient scandium. The potential of pentamethylcyclopentadienyl-dicarbollide derivatives of scandium to serve as efficient alpha olefin polymerization catalysts is discussed.