Ct. Qian et al., SYNTHESIS AND CRYSTAL-STRUCTURE OF 1,1'-(3-OXAPENTAMETHYLENE)-BRIDGEDBIS(INDENYL) ANSA-LANTHANOCENE CHLORIDES, Journal of the Chemical Society. Dalton transactions, (10), 1998, pp. 1607-1611
Several representative chiral ansa-lanthanocene chlorides have been sy
nthesized and characterised with a rac:meso ratio of 6:1 using an ethe
r-bridged bis(indenyl) ligand. The structure of these complexes was id
entified by X-ray crystallography in the solid state or H-1 NMR spectr
oscopy in solution. The ligand proved to be rather rigid leading to th
e favoured unsymmetric rac isomer. The H-1 NMR spectra indicated that
the configuration of the rac isomer in solution agrees well with that
in the solid state and, interestingly, the two bridged indenyl rings o
f the rac isomers slowly oscillated.