Alkoxides as ancillary ligands in organolanthanide chemistry: Synthesis, reactivity, α-olefin and diene polymerization by [Y(C 5Me 5)(OC 6H t3Bu 2)(μ-H)] 2

Abstract

Terminal olefins H 2CCHR (R=H, Me, n-Bu) react regiospecifically and irreversibly with μ-H dimer [Y(C 5Me 5)(OAr)(μ-H)] 2 ( 1) to give the μ- n-alkyl species trans-[Y(C 5Me 5)(OAr)] 2(μ-H)(μ-CH 2CH 2R) (R=H ( 2), Me ( 3), n-Bu ( 4)) respectively. Reaction of[Y(C 5Me 5)(OAr)(μ-D)] 2 ( 4-D) (prepared from (C 5Me 5)Y(OAr)CH(SiMe 3) 2 and D 2) with propene yields selectively only trans-[Y(C 5Me 5)(OAr)] 2(μ-D)(μ-CH 2CHDMe) ( 4-D), confirming the non-reversibility of olefin insertion. Compounds 1–4 polymerize ethene and are single-component catalysts for the polymerization of α-olefins and non-conjugated dienes. Dissolution of 1 in neat 1-hexene (to give 4 in situ) results in slow polymerization to yield poly(1-hexene) with M w=15700, M w/ M n=1.67. 1 cyclopolymerizes neat 1,5-hexadiene to poly(methylene-1,3-cyclopentane), rather than cyclization to methylenecyclopentane.