Synthesis of Hydroxyl-functionalized 3,4-Poly(2-aryl-1,3-butadiene)s
The polymerization of 2-(4-methylphenyl)-1,3-butadiene(2-MPBD)is performed using[C13H8CH2CH2-(NCHCCHN)C6H2Me3-2,4,6]Lu(CH2SiMe3)2(1),Ph2P(=NDip)(NDip)Lu(CH2Si-Me3)2(THF)(Dip=C6H3-2,6-iPr2;2),Ph2P(=NDip)(NC6H3-2-Et)Lu(CH2SiMe3)2(THF)(3)and Ph2P(=NDip)(NC6H3-2-Et)Sc(CH2SiMe3)2(THF)(4).The microstructures and thermal properties of resultant polymers are characterized by nuclear magnetic resonance spectroscopy(1H-NMR,13C-NMR),gel permeation chromatography(GPC)and differential scanning calorimetry(DSC).Complex 1,activated by[Ph3C][B(C6F5)4]and AliBu3,shows low catalytic activity and 3,4-selectivity(65.2％)for 2-MPBD polymerization.Under the same conditions,complex 2 is nearly inert.In contrast,complexes 3 and 4 demonstrate high 3,4-selectivity(98.1％and＞99％,respectively)and enable 100％conversion of 200 equivalents of 2-MPBD into polymers at 20 ℃ with 2 min.The resultant molecular weights increase with monomer-to-catalyst ratios varying from 200∶1 to 600∶1 with narrow molecular weight distributions of 1.12-1.25.Furthermore,complex 4 also shows high catalytic activity and high 3,4-selectivity for the polymerizations of 2-phenyl-1,3-butadiene,2-(3-methylphenyl)-1,3-butadiene,2-(4-pentylphenyl)-1,3-butadiene,2-(4-fluorophenyl)-1,3-butadiene and 2-(4-chlorophenyl)-1,3-butadiene.The resultant 3,4-poly(2-aryl-1,3-butadiene)s are readily transformed into hydroxyl functionalized polymers by the treatment of BH3 and H2O2.
Rare-earth metal catalystFunctional polyolefin3,4-SelectivityConjugated dieneReactive polyolefin intermediate
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