摘要
Coordination polymerization of renewable(E)-4,8-dimethyl-1,3,7-nonatriene(DMNT)has been performed using pyridyl-methylene-fluorenyl scandium complex 1,half-sandwich scandium complex 2,diiminophosphinato rare-earth metal complexes 3a—3c and 4a—4b,bis(phosphino)carbazolide yttrium complex 5 andβ-diketiminato yttrium complex 6.Fluorenyl scandium complexes 1 and 2,activated by[Ph3C][B(C6F5)4]and AliBu3,are moderately active and show perfect 1,2-regioselective(1,2>99%).Conversely,asymmetric diiminophophinato complexes 3a—3c promote the DMNT polymerization to produce high trans-1,4 regulated products with the activity trend:Sc<Lu<Y.Complexes 4—6 are virtually inactive for the DMNT polymerization although they are highly active in isoprene polymerization.A diblock copolymer bearing 3,4-polyisoprene block and trans-1,4-poly(DMNT)block is obtained using complex 3c in one-pot reaction.Hydrogenation of trans-1,4-poly(DMNT)affords an elastomer with a T_(g) of–10 ℃.The epoxidation reaction of trans-1,4-poly(DMNT)with 3-chloroperbenzoic acid transfers the pendant double bonds in the cis configuration into the epoxy groups.
基金
partially supported by the NSFC(project Nos.51773193,52073275).
