Ansa-metallocene derivatives - XLI. Chiral ansa-magnesocene complexes-syntheses, crystal structures and structural dynamics in solution

A series of chiral ansa-magnesocene complexes with dimethylsilanediyl- or ethanediyl-bridged, substituted cyclopentadienyl or indenyl ligands, prepared in form of their THF adducts, has been structurally characterized by diffractometric crystal structure determination and by NMR studies in solution. The hapticities of the ring ligands vary between eta(1) and eta(5), depending on the nature of the interanular bridge and the C-5 ring substituents. A racemic configuration is preferred by Mg bis-indenyl complexes with either Me2Si- or C2H4-bridges in the solid state and in solution, while meso isomers predominate for t-butyl-substituted ansa-magnesocenes. (C) 1998 Elsevier Science S.A.