SYNTHESIS, STRUCTURE, DYNAMIC PROPERTIES, AND INDENYL TRANSFER-REACTIONS OF (ALME2(THF)(INDENYL))(2)SIME2

The reaction of Li2SBI (SBI = Me2Si(1-indenyl)(2)) with 2 equiv of AlM e2Cl in Et2O, followed by treatment with THF, affords {AlMe2(THF)(inde nyl)}(2)-SiMe2 (1), which is isolated as a ca. 1/1 mixture of rac and meso isomers, from which rac-1 is obtained by crystallization from tol uene. An. X-ray crystallographic analysis establishes that rac-1 exist s as the 1,3 isomer, i.e., e2(THF)-1-indenyl)}(3-{AlMe2(THF)}-1-indeny l)SiMe2 in the solid state. NMR studies establish that in toluene-d(8) , rac-1 exists as a 2/1 mixture of 1,3 and 1,1 Al-indenyl isomers whic h interconvert rapidly on the NMR time scale at room temperature. Rac- 1 undergoes slow isomerization to a 1/1 rac/meso mixture (3 days, 23 d egrees C, benzene) and also undergoes slow partial disproportionation by ligand redistribution (28% conversion, 2 days, 23 degrees C, benzen e). Compound 1 (1/1 to 1.4/1 rac/meso mixture) reacts with Zr(NMe2)(4) and Hf(NMe2)(4) under mild conditions to yield (SBI)Zr(NMe2)(2) in >9 0% NMR yield (rac/meso = 4.5/1) and rac-(SBI)Hf(NMe2)(2) in 61% isolat ed yield, respectively.