SYNTHESIS AND X-RAY CRYSTAL-STRUCTURES OF ,2'-PROPYLIDENE-BIS(1-INDENYL)ZIRCONIUM-DICHLORIDE AND ,2'-PROPYLIDENE-BIS(1-INDENYL)ZIRCONIUM-DICHLORIDE

An improved synthesis of 2,2'-bis(1-indenyl)propane and the correspond ing ansa-complexes of zirconium are reported. Synthesis of a mixture o f rac- and meso-2,2'-propylidene-bis(l-indenyl)zirconium dichlorides i nvolves a treatment of ZrCl4 with bis[3-(trialkyltin)inden-1-yl]propan e, where alkyl = ethyl, butyl, in toluene. This reaction gives the pro ducts in 92% yield and might be a convenient synthetic pathway to a nu mber of straightforward ansa-metallocenes. Both rac- and meso-2,2'-pro pylidene-bis( I-indenyl)zirconium dichlorides were separated and isola ted using simple work-up processes, and characterized by X-ray crystal structure analysis (rac-:C2/c; a = 15.903(3)Angstrom, b = 11.105(2)An gstrom and c = 11.520(2)Angstrom; beta = 121.61(3)degrees; Z = 4; V = 1732.6(5) Angstrom(3): R = 0.0350; mese-: P (1) over bar; a = 9.739(2) Angstrom, b = 12.798(4)Angstrom and c = 15.322(4)Angstrom; alpha = 101 .18(2)degrees; beta = 121.61(2)degrees; gamma = 90.54(2)degrees, Z = 4 ; V = 1795.4(8)Angstrom(3); R = 0.0417).