Synthesis and Characterization of ansa-Bis(3-chiral group substituted indenyl) Zirconium Complexes

Ethylene or methylene bridged bis(indenyl) compounds 1a similar to 3a bearing chiral substituent have been obtained by introducing (+)-neomenthyl or (+)-isocamphyl to the 3-position of indenyl ring. Two C-2-symmetric ethylene bridged bis(indenyl) zirconium complexes 2b and 3b have been isolated readily from the reaction of the dilithium salts of these compounds with zirconium tetrachloride. The purification of corresponding meso-like, C-1-symmetric complexes 2c and 3c was however not successful. All of the proligand compounds and zirconium complexes have been characterized by H-1 NMR, C-13 NMR spectra and elemental analysis (or HRMS). The molecular structure of 2c was further determined by X-ray single crystal diffraction analysis. The crystal of 2c belongs to orthorhombic, space group P2(1)2(1)2(1) with cell parameters a=10.946(4) angstrom, b=13.377(4) angstrom, c=24.294(8) angstrom, alpha=beta=gamma=90 degrees, M-r=694.94, V=3557(2) angstrom(3), D-c=1.298 g/cm(3), Z=4, F(000)=1464, mu=0.486 mm(-1), R=0.0296 and wR=0.0683 [I>2 sigma(I)].