A NEW LIGAND ENVIRONMENT IN ORGANOLANTHANOID CHEMISTRY - STERICALLY HINDERED, CHELATING DIOLATO LIGANDS AND THE X-RAY STRUCTURE OF [LA((CH(SIME3)2)(1,1'-(2-OC6H2BUT2-3,5)2)(THF)3] (THF = TETRAHYDROFURAN)

[La{CH(SiMe3)2}3] 1 reacts with 1 equiv. of 3,3',5,5'-tetra-tert-butylbiphenyl-2,2'-diol 2 to afford the monomeric chelate [La{CH(SiMe3)2}{1,1'-(2-OC6H2Bu(t)2-3,5)2}] 4, whose mono-5, and crystallographically characterised tris-thf adducts 6 have been synthesized; its reaction with 3,3'-bis(triphenylsilyl)-1,1'-binaphthyl-2,2'-diol 3c affords [La{CH(SiMe3)2}{1,1'-(2-OC10H5SiPh3-3)2}(OEt2)] 7.