A series of linear and X-shaped oligo（para-phenylene） derivatives functionalized with fluorene ethynylenes 1,3 and 4 were synthesized through sequent Sonogashira coupling and Suzuki-Miyaura reaction in high yield.Th...A series of linear and X-shaped oligo（para-phenylene） derivatives functionalized with fluorene ethynylenes 1,3 and 4 were synthesized through sequent Sonogashira coupling and Suzuki-Miyaura reaction in high yield.The electron-donating group-OCH3 and electron-withdrawing counterparts-CF3 were introduced to tune the spectra properties of compounds 3 and 4.The detail investigation of their photophysical properties in solution and film indicated that the introduction of both -OCH3 and -CF3 makes maximum emission distinct red-shift in comparison with parent compound 1,but the latter more prominently.展开更多
A series of linear and V-shaped oligo(phenylene ethynylene) derivatives 1-3 were synthesized through sequent Sonogashira coupling and propargyl alcohol deprotection reaction in high yields.The alkoxy chains(i.e.,n-hex...A series of linear and V-shaped oligo(phenylene ethynylene) derivatives 1-3 were synthesized through sequent Sonogashira coupling and propargyl alcohol deprotection reaction in high yields.The alkoxy chains(i.e.,n-hexyloxy groups) were introduced to assure good solubility of compounds 1-3 in common solvents.The photophysical properties of 1-3 in solution depend strongly on the geometries of these compounds.展开更多
Novel n-conjugated polymers constituted of 2,1,3-benzothiadiazole or cyano-containing unit copolymers were synthesized and characterized by UV-Vis, IR and PL.
A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H2O molecu...A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H2O molecules accumulated in the vicinity as recently reported by Na et al. [Nanotechnology 18 424001 （2007）]. The numerical results show that the hydrogen bonds between the oxygen atoms of the oligomeric phenylene ethynylene molecule and H2O molecules result in the localisation of the molecular orbitals and lead to the lower transition peaks. The H2O molecular chains accumulated in the vicinity of the molecular junction can not only change the electronic structure of the molecular junctions, but also open additional electronic transport pathways. The obvious influence of H2O molecules on the electronic structure of the molecular junction and its electronic transport properties is thus demonstrated.展开更多
The absorption spectra of the p-phenylene-ethynylene（p-PPE） oligomers（up to n = 12） were estimated by DFT and TD-DFT methods. The effective conjugation length（ECL） of the corresponding polymer was obtained by ex...The absorption spectra of the p-phenylene-ethynylene（p-PPE） oligomers（up to n = 12） were estimated by DFT and TD-DFT methods. The effective conjugation length（ECL） of the corresponding polymer was obtained by extrapolating the first excitation energies of the oligmers to infinite chain length with an alternative exponential function. The absorption spectral red-shift mainly depends on the ？-conjugation segment of oligomers resulting from the planarization of the backbone. The excitation mechanism of the rotamer has been investigated sufficiently by analyzing the orbital density variation upon the conformational rotations around the cylindrical triple-bonded carbon which is believed to impact significantly on the optical spectrum. The calculated results further indicate that rotation about the cylindrical triple bond interrupts the conjugation of rod-like oligomers to lead an angle-dependence of the corresponding excitation energy. The results are helpful to interpret the conformational-dependent spectroscopic phenomena of p-phenyleneethynylene and derivatives oligomers and polymers observed in ensemble and single molecule spectroscopy.展开更多
The title copolymer(PDEBO) was synthesized. The thermal characteristics of the polymer were determined by means of DSC and TGA, revealing that the polymer has a good thermal stability. The X-ray diffraction measuremen...The title copolymer(PDEBO) was synthesized. The thermal characteristics of the polymer were determined by means of DSC and TGA, revealing that the polymer has a good thermal stability. The X-ray diffraction measurements of the thin films showed that the polymer is disorder. Electroluminescence(EL) in the green region of the spectrum with a maximum at 500 nm was observed from the polymer films sandwiched between indium-tin-oxide and an Al electrode.展开更多
Alternating copolymerization of 9,9-dihexyl-2,7-dibromofluorene, N-hexyl-2,7-dibromocarbazole (HCz) with diethynyldimethylsilane, diethynyldiphenylsilane, has been investigated using Sonogashira coupling reaction. Pho...Alternating copolymerization of 9,9-dihexyl-2,7-dibromofluorene, N-hexyl-2,7-dibromocarbazole (HCz) with diethynyldimethylsilane, diethynyldiphenylsilane, has been investigated using Sonogashira coupling reaction. Photophysical properties of the resulting copolymers were investigated with UV-Vis absorption and photoluminescence spectroscopy. All the copolymers in chloro-form solution showed absorption peaks at 270 - 280 nm with shoulder peaks at around 380 nm derived from π-π* transition or intra-molecular charge transfer through σ-π moiety, respectively. The chloroform solutions of the copolymers showed broad emission peaks at 415 - 425 nm. The emission wave lengths of the copolymers in the solid state (cast film) detected at 360 - 385 nm were remarkably blue-shifted in comparison with those in the chloroform solutions. Hydrosilylation reaction of the copolymers with 1,4-bis(dimethylsilyl)benzene yielded networked copolymers soluble in chloroform, indicating formation of branching polymers. The chloroform solutions of the HCz-based networked copolymers showed bimodal emission derived from new highly energy states in the σ-π conjugation.展开更多
Poly（arylene ethynylene）s,P1 and P2 containing 1,3,5-triazine and chalcone unites respectively,were synthesized by Sonogashira coupling reaction.These polymers exhibited good solubility in common organic solvents,su...Poly（arylene ethynylene）s,P1 and P2 containing 1,3,5-triazine and chalcone unites respectively,were synthesized by Sonogashira coupling reaction.These polymers exhibited good solubility in common organic solvents,such as dichloromethane,chloroform,and tetrahydrofuran.The molecular weight Mw of P1 was 6390 with polydispersity（PDI） being 2.33 and that of P2 was 6870 with polydispersity（PDI） being 1.85 characterized by GPC.The photophysical properties were analyzed by solution and solid state photoluminescence spectroscopy.P1 emitted blue fluorescence at around 441 nm in CH2Cl2 or THF solutions under UV excitation.The photoluminescence behavior of P2 was dependent on the solvent,with green emitting light at around 550 in CH2Cl2 solution and 500 nm in THF solution.Powder photoluminescence spectra of P1 and P2 showed that the peak wavelengths respectively shifted to 530 and 605 nm.展开更多
Poly（phenylene ethynylene）s （P1） with 4-vinylaniline pendant groups were successfully prepared by the Sonogashira coupling polymerization bevween 1,4-diethynyl-2,5-bis（pentyloxy）benzene and 4-[2-（2,5-dibromophe...Poly（phenylene ethynylene）s （P1） with 4-vinylaniline pendant groups were successfully prepared by the Sonogashira coupling polymerization bevween 1,4-diethynyl-2,5-bis（pentyloxy）benzene and 4-[2-（2,5-dibromophenyl）vinyl]- aniline. In comparison with its analogue P2 without amino group, the emission of F＇I is only enihanced by aggregation when adding n-hexane into its THF solution, exhibiting an aggregation-induced emission enhancement （AIEE） effect. When methanol or water instead of hexane was added into THF solution, P1, however, didn＇t show AII：~E. The results indicated that amino groups strengthen the inter-chain and intra-chain interactions in P1 and restrict the no^-radiative energy transition. This strategy can provide a platform for developing highly sensitive and efficient bio- and chemosensors.展开更多
The poly(2,5-dipentyloxy-para-phenylene ethynylene)(P) was synthesized by Pd-catalyzed Sonogashira coupling reaction.Due to causing energy transfer between the nitrobenzene’s quenchers and the polymer chains through ...The poly(2,5-dipentyloxy-para-phenylene ethynylene)(P) was synthesized by Pd-catalyzed Sonogashira coupling reaction.Due to causing energy transfer between the nitrobenzene’s quenchers and the polymer chains through the charge-transfer interaction,the fluorescence quenched properties of P varied obviously with the para-substituting group’s structure in the nitrobenzene derivatives.The fluorescence quenching efficiency of quenchers improved with increasing of electron repulsion capability of the para-substituting group.The fluorescence quenching efficiency increased nonlinearly with the concentration of the quenchers and had,however,no relation with the quenching time.展开更多
基金Beijing Natural Science Foundation(No.2093033)Scientific Research Project of Beijing Educational Committee(Nos.KM 200910020012 and KM 201010020002) for financial support
文摘A series of linear and X-shaped oligo（para-phenylene） derivatives functionalized with fluorene ethynylenes 1,3 and 4 were synthesized through sequent Sonogashira coupling and Suzuki-Miyaura reaction in high yield.The electron-donating group-OCH3 and electron-withdrawing counterparts-CF3 were introduced to tune the spectra properties of compounds 3 and 4.The detail investigation of their photophysical properties in solution and film indicated that the introduction of both -OCH3 and -CF3 makes maximum emission distinct red-shift in comparison with parent compound 1,but the latter more prominently.
基金Beijing Natural Science Foundation(No.2093033)Scientific Research Project of Beijing Educational Committee(No.KM200910020012) for financial support.
文摘A series of linear and V-shaped oligo(phenylene ethynylene) derivatives 1-3 were synthesized through sequent Sonogashira coupling and propargyl alcohol deprotection reaction in high yields.The alkoxy chains(i.e.,n-hexyloxy groups) were introduced to assure good solubility of compounds 1-3 in common solvents.The photophysical properties of 1-3 in solution depend strongly on the geometries of these compounds.
基金We are gratefully acknowledged financial support of this work by the National Natural Science Foundation of China （No.20274039）.
文摘Novel n-conjugated polymers constituted of 2,1,3-benzothiadiazole or cyano-containing unit copolymers were synthesized and characterized by UV-Vis, IR and PL.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10804064 and 10674084)
文摘A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H2O molecules accumulated in the vicinity as recently reported by Na et al. [Nanotechnology 18 424001 （2007）]. The numerical results show that the hydrogen bonds between the oxygen atoms of the oligomeric phenylene ethynylene molecule and H2O molecules result in the localisation of the molecular orbitals and lead to the lower transition peaks. The H2O molecular chains accumulated in the vicinity of the molecular junction can not only change the electronic structure of the molecular junctions, but also open additional electronic transport pathways. The obvious influence of H2O molecules on the electronic structure of the molecular junction and its electronic transport properties is thus demonstrated.
基金supported by the National Natural Science Foundation of China(21373012)the Key Project of Educational Committee of Anhui Province(KJ2010A143)
文摘The absorption spectra of the p-phenylene-ethynylene（p-PPE） oligomers（up to n = 12） were estimated by DFT and TD-DFT methods. The effective conjugation length（ECL） of the corresponding polymer was obtained by extrapolating the first excitation energies of the oligmers to infinite chain length with an alternative exponential function. The absorption spectral red-shift mainly depends on the ？-conjugation segment of oligomers resulting from the planarization of the backbone. The excitation mechanism of the rotamer has been investigated sufficiently by analyzing the orbital density variation upon the conformational rotations around the cylindrical triple-bonded carbon which is believed to impact significantly on the optical spectrum. The calculated results further indicate that rotation about the cylindrical triple bond interrupts the conjugation of rod-like oligomers to lead an angle-dependence of the corresponding excitation energy. The results are helpful to interpret the conformational-dependent spectroscopic phenomena of p-phenyleneethynylene and derivatives oligomers and polymers observed in ensemble and single molecule spectroscopy.
基金Supported by the National Natural Science Foundation of China(No.2 99740 2 5 ) and Zhejiang Provincial Nature Science Foundation(No.5 9910 0 ) State Key L aboratory of Silicon MaterialsL aboratory of Organnic Solids,Institute of Chemistry,Chinese Acade
文摘The title copolymer(PDEBO) was synthesized. The thermal characteristics of the polymer were determined by means of DSC and TGA, revealing that the polymer has a good thermal stability. The X-ray diffraction measurements of the thin films showed that the polymer is disorder. Electroluminescence(EL) in the green region of the spectrum with a maximum at 500 nm was observed from the polymer films sandwiched between indium-tin-oxide and an Al electrode.
文摘Alternating copolymerization of 9,9-dihexyl-2,7-dibromofluorene, N-hexyl-2,7-dibromocarbazole (HCz) with diethynyldimethylsilane, diethynyldiphenylsilane, has been investigated using Sonogashira coupling reaction. Photophysical properties of the resulting copolymers were investigated with UV-Vis absorption and photoluminescence spectroscopy. All the copolymers in chloro-form solution showed absorption peaks at 270 - 280 nm with shoulder peaks at around 380 nm derived from π-π* transition or intra-molecular charge transfer through σ-π moiety, respectively. The chloroform solutions of the copolymers showed broad emission peaks at 415 - 425 nm. The emission wave lengths of the copolymers in the solid state (cast film) detected at 360 - 385 nm were remarkably blue-shifted in comparison with those in the chloroform solutions. Hydrosilylation reaction of the copolymers with 1,4-bis(dimethylsilyl)benzene yielded networked copolymers soluble in chloroform, indicating formation of branching polymers. The chloroform solutions of the HCz-based networked copolymers showed bimodal emission derived from new highly energy states in the σ-π conjugation.
文摘Poly（arylene ethynylene）s,P1 and P2 containing 1,3,5-triazine and chalcone unites respectively,were synthesized by Sonogashira coupling reaction.These polymers exhibited good solubility in common organic solvents,such as dichloromethane,chloroform,and tetrahydrofuran.The molecular weight Mw of P1 was 6390 with polydispersity（PDI） being 2.33 and that of P2 was 6870 with polydispersity（PDI） being 1.85 characterized by GPC.The photophysical properties were analyzed by solution and solid state photoluminescence spectroscopy.P1 emitted blue fluorescence at around 441 nm in CH2Cl2 or THF solutions under UV excitation.The photoluminescence behavior of P2 was dependent on the solvent,with green emitting light at around 550 in CH2Cl2 solution and 500 nm in THF solution.Powder photoluminescence spectra of P1 and P2 showed that the peak wavelengths respectively shifted to 530 and 605 nm.
基金financially supported by the National Natural Scientific Foundation of China(Nos.51073026 and 21004004)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Nos.2009110111003 l and 20101101120029)Excellent Young Scholars Research Fund of Beijing Institute of Technology(No.2009Y0914)
文摘Poly（phenylene ethynylene）s （P1） with 4-vinylaniline pendant groups were successfully prepared by the Sonogashira coupling polymerization bevween 1,4-diethynyl-2,5-bis（pentyloxy）benzene and 4-[2-（2,5-dibromophenyl）vinyl]- aniline. In comparison with its analogue P2 without amino group, the emission of F＇I is only enihanced by aggregation when adding n-hexane into its THF solution, exhibiting an aggregation-induced emission enhancement （AIEE） effect. When methanol or water instead of hexane was added into THF solution, P1, however, didn＇t show AII：~E. The results indicated that amino groups strengthen the inter-chain and intra-chain interactions in P1 and restrict the no^-radiative energy transition. This strategy can provide a platform for developing highly sensitive and efficient bio- and chemosensors.
文摘The poly(2,5-dipentyloxy-para-phenylene ethynylene)(P) was synthesized by Pd-catalyzed Sonogashira coupling reaction.Due to causing energy transfer between the nitrobenzene’s quenchers and the polymer chains through the charge-transfer interaction,the fluorescence quenched properties of P varied obviously with the para-substituting group’s structure in the nitrobenzene derivatives.The fluorescence quenching efficiency of quenchers improved with increasing of electron repulsion capability of the para-substituting group.The fluorescence quenching efficiency increased nonlinearly with the concentration of the quenchers and had,however,no relation with the quenching time.
