We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precu...We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA （P2） was derived by desilylation of the pristine PA with trimethylethynylsilane side chains （P1）. P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane （M） under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps （from P1 to P3 via precursor P2） and one-pot （from P1 to P3 without separation and purification of P2） were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.展开更多
New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotri...New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3 and 6 with 1-heptyne and 1-octyne have been achieved with WCl6- and TaCl5-Ph4Sn catalysts, respectively, giving soluble linear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2 x 10(5)) in high yields (up to 98%). The structures and properties of the polymers are characterized and evaluated by R NMR, TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stability and emit strong blue light upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL was observed in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has been achieved in 2, which are the best results for substituted polyacetylenes attainable so far.展开更多
基金partially supported by the National Natural Science Foundation of China (21074113,20634020 & 20974028)the National Basic Research Program of China (973 Program,2009CB623605)+1 种基金the Research Grants Council of Hong Kong (603509 & HKUST2/CRF/10)the University Grants Committee of Hong Kong (AoE/P-03/08)
文摘We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA （P2） was derived by desilylation of the pristine PA with trimethylethynylsilane side chains （P1）. P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane （M） under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps （from P1 to P3 via precursor P2） and one-pot （from P1 to P3 without separation and purification of P2） were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.
文摘New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3 and 6 with 1-heptyne and 1-octyne have been achieved with WCl6- and TaCl5-Ph4Sn catalysts, respectively, giving soluble linear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2 x 10(5)) in high yields (up to 98%). The structures and properties of the polymers are characterized and evaluated by R NMR, TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stability and emit strong blue light upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL was observed in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has been achieved in 2, which are the best results for substituted polyacetylenes attainable so far.
