A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All t...A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All thereactions proceed smoothly and soluble polymers of high molecular weights(M_w up to 3.8×10~4)are obtained in high yields(up to 97%).展开更多
Polycyclotrimerization of diynes was explored as a new route to hyperbranched polymers in this investigation. Polymerization of terminal diynes of 1,8-nonadiyne and 1,9-decadiyne was studied using TaCl5, NbCl5, Mo(CO)...Polycyclotrimerization of diynes was explored as a new route to hyperbranched polymers in this investigation. Polymerization of terminal diynes of 1,8-nonadiyne and 1,9-decadiyne was studied using TaCl5, NbCl5, Mo(CO)(4)(nbd) and [Mo(CO)(3)cp](2) as catalysts (where nbd = 2,5-norbornadiene, cp = cyclopentadiene). A soluble polymer was obtained when the polymerization of 1,9-decadiyne was initiated by TaCl5 at low temperature (0 degrees C). The polymer, however, became partially soluble after purification, possibly due to the postpolymerization-induced crosslinking. NbCl5-catalyzed polymerization of 1,9-bis(trimethylsilyl)- 1,8-nonadiyne gave a completely soluble polymer. Soluble polymers were also obtained from the polymerization of 3,9-dodecadiyne initiated by NbCl5, Mo(CO)(4)(nbd), [Mo(CO)(3)cp](2), PdCl2-ClSiMe3 and Pd/C-ClSiMe3. IR, UV, and NMR spectroscopic analysis revealed that different catalysts gave polymers with different structures, ranging from linear polyenes to hyperbranched polyphenylenes. The polymers absorb UV light at around 250 nm and emit fluorescence at 340 nm when they are excited at 248 nm.展开更多
A new bis(aroylacetylene) containing tfiazole and fluorene moieties is synthesized by click chemistry. Polycyclotrimerization of the monomer is catalyzed by piperidine in refluxed dioxane,furnishing a regioregular pol...A new bis(aroylacetylene) containing tfiazole and fluorene moieties is synthesized by click chemistry. Polycyclotrimerization of the monomer is catalyzed by piperidine in refluxed dioxane,furnishing a regioregular poly(aroylarylene) in a satisfactory yield.The hyperbranched structure of the polymer is characterized spectroscopically with satisfactory results.The polymer enjoys no metal detriment and is soluble in common organic solvents such as tetrahydrofuran (THF),chloroform,dichloromethane (DCM),and N,N-...展开更多
Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polym...Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polymers possess low intrinsic viscosities and high thermal stabilities, losing little of their weights when heated to 〉 400℃. Upon pyrolysis at 〉 800℃, the polymers graphitize with high char yields （up to 86%）. Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C60, a well-known optical limiter. Poly（alkenephenylenes）, poly（aroylarylenes） and polyynes are readily cross-linkable by UV irradiation, serving as excellent photoresist materials for the generation of patterns with nanometer resolution. Thin films of hyperbranched polyynes exhibit very high refractive indexes （n up to 1.86）. The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls, which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities （Ms up to ca. 118 emu/g） and near-zero magnetic losses.展开更多
New hyperbranched polyphenylenes with high molecular weights are synthesized by the copolycyclotrimerizations of 1,4-diethynylbenzene (I) with phenylacetylene (A), 1-octyne (B), and 1-dodecyne (C) catalyzed by TaCl5-P...New hyperbranched polyphenylenes with high molecular weights are synthesized by the copolycyclotrimerizations of 1,4-diethynylbenzene (I) with phenylacetylene (A), 1-octyne (B), and 1-dodecyne (C) catalyzed by TaCl5-Ph4Sn. The polymers are completely soluble in common solvents such as toluene, THF, chloroform, and dichloromethane. The polymers are characterized by spectroscopic methods and all of the polymers give satisfactory analysis data corresponding to their expected molecular structures.展开更多
基金This project was supported by the Research Grants Council of Hong Kong(Nos.603304,604903HKUST6085/02P).
文摘A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All thereactions proceed smoothly and soluble polymers of high molecular weights(M_w up to 3.8×10~4)are obtained in high yields(up to 97%).
基金This workw was in part supported by the Earmarked Research Grants of the Hong Kong Research Grants Council(HKUST6062/98P and HKUST6149/97P)
文摘Polycyclotrimerization of diynes was explored as a new route to hyperbranched polymers in this investigation. Polymerization of terminal diynes of 1,8-nonadiyne and 1,9-decadiyne was studied using TaCl5, NbCl5, Mo(CO)(4)(nbd) and [Mo(CO)(3)cp](2) as catalysts (where nbd = 2,5-norbornadiene, cp = cyclopentadiene). A soluble polymer was obtained when the polymerization of 1,9-decadiyne was initiated by TaCl5 at low temperature (0 degrees C). The polymer, however, became partially soluble after purification, possibly due to the postpolymerization-induced crosslinking. NbCl5-catalyzed polymerization of 1,9-bis(trimethylsilyl)- 1,8-nonadiyne gave a completely soluble polymer. Soluble polymers were also obtained from the polymerization of 3,9-dodecadiyne initiated by NbCl5, Mo(CO)(4)(nbd), [Mo(CO)(3)cp](2), PdCl2-ClSiMe3 and Pd/C-ClSiMe3. IR, UV, and NMR spectroscopic analysis revealed that different catalysts gave polymers with different structures, ranging from linear polyenes to hyperbranched polyphenylenes. The polymers absorb UV light at around 250 nm and emit fluorescence at 340 nm when they are excited at 248 nm.
基金supported by the National Natural Science Foundation of China (Nos.20634020 and 50703033)the Ministry of Science & Technology (No.2009CB623605)+2 种基金the Research Grants Council of Hong Kong (Nos.603008,602707 and 602706)A.J.Q.acknowledges the support from the China Postdoctoral Science Foundation (No.20070420228)B.Z.T.thanks the support from the Cao Guangbiao Foundation of Zhejiang University.
文摘A new bis(aroylacetylene) containing tfiazole and fluorene moieties is synthesized by click chemistry. Polycyclotrimerization of the monomer is catalyzed by piperidine in refluxed dioxane,furnishing a regioregular poly(aroylarylene) in a satisfactory yield.The hyperbranched structure of the polymer is characterized spectroscopically with satisfactory results.The polymer enjoys no metal detriment and is soluble in common organic solvents such as tetrahydrofuran (THF),chloroform,dichloromethane (DCM),and N,N-...
基金This work was partially supported by the Hong Kong Research Grants Council,the University Grants Committee of Hong Kong,and the National Natural Science Foundation of China.
文摘Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polymers possess low intrinsic viscosities and high thermal stabilities, losing little of their weights when heated to 〉 400℃. Upon pyrolysis at 〉 800℃, the polymers graphitize with high char yields （up to 86%）. Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C60, a well-known optical limiter. Poly（alkenephenylenes）, poly（aroylarylenes） and polyynes are readily cross-linkable by UV irradiation, serving as excellent photoresist materials for the generation of patterns with nanometer resolution. Thin films of hyperbranched polyynes exhibit very high refractive indexes （n up to 1.86）. The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls, which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities （Ms up to ca. 118 emu/g） and near-zero magnetic losses.
基金This work was supported by the Research Grants Council of Hong Kong (Nos. 603304, 604903 and HKUST6085/02P).
文摘New hyperbranched polyphenylenes with high molecular weights are synthesized by the copolycyclotrimerizations of 1,4-diethynylbenzene (I) with phenylacetylene (A), 1-octyne (B), and 1-dodecyne (C) catalyzed by TaCl5-Ph4Sn. The polymers are completely soluble in common solvents such as toluene, THF, chloroform, and dichloromethane. The polymers are characterized by spectroscopic methods and all of the polymers give satisfactory analysis data corresponding to their expected molecular structures.
