TRIS(INDENYL)LANTHANUM(III) DERIVATIVES WITH 2 STEREOGENIC CENTERS - CRYSTAL-STRUCTURES AND SOLUTION NMR-SPECTROSCOPY OF THE ADDUCTS [(C9H7)(3)LA.L] WITH L=(R)-(-METHYL-P-TOLYLSULPHOXIDE AND TRIPHENYLPHOSPHINOXIDE())

Three new adducts of the type [(C9H7)(3)La . L] with L = (R)-(+)-methy l-p-tolylsulphoxide 1, triphenylphosphinoxide 2 and diphenylsulphoxide 3 have been prepared and further characterized. The crystal structure s of 1 and 2 were determined from single crystals. 1 crystallizes as o ne distinct epimeric form with two 'equatorially' and one 'meridionall y' oriented C9H7 ligands. Space group P2(1); cell parameters a = 838.3 0(10), b = 966.5(3), c = 1770.5(7)pm, beta = 90.82(2)degrees. Crystals of 2 contain two crystallographically equivalent diastereomers with t hree disordered but essentially 'equatorial' C9H7 ligands. The P(C6H5) (3) propellers adopt either of two possible enantiomorphic configurati ons. Space group R (3) over bar; cell parameters a = b = 1451.1(3), c = 3136.6(7)pm. The solution H-1 NMR spectra of 1-3 clearly reflect rap id intramolecular motion of the C9H7 ligands. The quasi-first-order sp ectrum of 1 is indicative of significant diastereotopic splitting, dis playing a total of seven individual C9H7 proton resonances.