Efficient luminescent composite nanofibers,composed of polystyrene(PS,Mw=250000) and europium complex Eu(TTA)3phen(TTA=2-thenoyltrifluoroacetone,phen=1,10-phenanthroline) with diameters ranging from 350 nm to 700 nm,w...Efficient luminescent composite nanofibers,composed of polystyrene(PS,Mw=250000) and europium complex Eu(TTA)3phen(TTA=2-thenoyltrifluoroacetone,phen=1,10-phenanthroline) with diameters ranging from 350 nm to 700 nm,were prepared by electrospinning and characterized by scanning electron microscope(SEM),Fourier transform infrared spectroscopy(FT-IR),fluorescence spectroscopy,and thermogravimetric analysis(TG).The room-temperature fluorescence spectra of the composite nanofibers were composed of the typical E...展开更多
Quantum density functional theory （DFT） results are reported for the building block [LaL^1（NO3）] of La complex [LaL^1（NO3）]NO3·5H2O （L^1 = （CH3）2CHCH2CH（NCHC4H3O）COO^-）. The structure was optimized an...Quantum density functional theory （DFT） results are reported for the building block [LaL^1（NO3）] of La complex [LaL^1（NO3）]NO3·5H2O （L^1 = （CH3）2CHCH2CH（NCHC4H3O）COO^-）. The structure was optimized and the calculation results show that the lanthanum ion is coordinated by one nitrogen atom and three oxygen atoms of L^1 and two oxygen atoms of nitrate ion. The bond length of La-N is 0.2637 nm and the average length of La-O is 0.2526 nm, which are consistent with the literatures. In addition, the stabilities, electronic structural characteristics and IR spectra of the complex have been analyzed, which describe the coordination of lanthanum ion with other atoms in detail.展开更多
The Langmuir-Blodgett (LB) technique was used for studying enhanced lumines-cence of Eu (TTA)3 Phen (acceptor) by La (TTA)3 Phen (donor). LB films studied here are:(1) [0. 5% Eu (TTA)3 Phen + 99. 5% La (TTA)3 Phen]: A...The Langmuir-Blodgett (LB) technique was used for studying enhanced lumines-cence of Eu (TTA)3 Phen (acceptor) by La (TTA)3 Phen (donor). LB films studied here are:(1) [0. 5% Eu (TTA)3 Phen + 99. 5% La (TTA)3 Phen]: AA = 1: 1; (2) [0. 5%Eu(TTA)3 Phen+99. 5%AA]: AA= 1: 1; (3) La(TTA)3 Phen: AA= 1: 1. These filmscould form stable monolayers at air/water surface. The fluorescence intensity of LB 1 was 65times stronger than that of LB2. This signifies that the luminescence intensity ofEu(TTA)3 Phen could be enhanced by La (TTA)3 Phen clearly. Low angle X-ray diffrac-tog ram of LB1 showed that the film has a period layered structure. To study the intermolec-ular energy transfer, different structures of the multilayer were designed by combining LB2(layer of acceptor) with LB3(layer of donor). The results indicated that the intermolecularenergy transfer occurred in a short-range (<3 nm) and at the position of head-head in Y-typemodel. The influence of the interface on the energy transfer was prominent. The process ofenergy transfer was carried out via the triplet state of TTA.展开更多
The metathesis reaction between pyrrolidinyl-ethylene fluorenyl lithium salts with in situ prepared cationic rare-earth metal dialkyl species[Ln(CH_(2)SiMe_(3))_(2)(THF)_(x)][BPh_(4)]afford efficiently the correspondi...The metathesis reaction between pyrrolidinyl-ethylene fluorenyl lithium salts with in situ prepared cationic rare-earth metal dialkyl species[Ln(CH_(2)SiMe_(3))_(2)(THF)_(x)][BPh_(4)]afford efficiently the corresponding constrained-geometry complexes L^(1)Ln(CH_(2)SiMe_(3))_(2)(L^(1)=FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(1a),Lu(1b),Sc(1c))and L^(2)Ln(CH_(2)SiMe_(3))_(2)(L^(2)=(2,7-di-tert-butyl)FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(2a),Lu(2b),Sc(2c))in good yields.All these complexes were characterized by NMR spectroscopy,and the solid-state molecular structure of yttrium complex 1a was defined with single-crystal X-ray diffraction analysis.The catalytic performance of these complexes towards 2-vinylpyridine polymerization was investigated,where these complexes alone can efficiently promote the polymerization of 2-vinylpyridine giving isotactic poly(2-vinylpyridine).Upon the activation with[Ph_(3)C][B(C_(6)F_(5))_(4)],the yttrium and lutetium complexes also afford isotactic poly(2-vinylpyridine),while the scandium complexes produce syndiotactic poly(2-vinylpyridine).展开更多
基金supported by the National Natural Science Foundation of China (50503002)the National High-Tech Research Developing Foundation (863,2003AA324030)+2 种基金National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China (2006BAE03B)Program for New Century Excellent Talents in University (NCET)Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT,IRT0807)
文摘Efficient luminescent composite nanofibers,composed of polystyrene(PS,Mw=250000) and europium complex Eu(TTA)3phen(TTA=2-thenoyltrifluoroacetone,phen=1,10-phenanthroline) with diameters ranging from 350 nm to 700 nm,were prepared by electrospinning and characterized by scanning electron microscope(SEM),Fourier transform infrared spectroscopy(FT-IR),fluorescence spectroscopy,and thermogravimetric analysis(TG).The room-temperature fluorescence spectra of the composite nanofibers were composed of the typical E...
基金This work was supported by the National Natural Science Foundation of China (20203011)
文摘Quantum density functional theory （DFT） results are reported for the building block [LaL^1（NO3）] of La complex [LaL^1（NO3）]NO3·5H2O （L^1 = （CH3）2CHCH2CH（NCHC4H3O）COO^-）. The structure was optimized and the calculation results show that the lanthanum ion is coordinated by one nitrogen atom and three oxygen atoms of L^1 and two oxygen atoms of nitrate ion. The bond length of La-N is 0.2637 nm and the average length of La-O is 0.2526 nm, which are consistent with the literatures. In addition, the stabilities, electronic structural characteristics and IR spectra of the complex have been analyzed, which describe the coordination of lanthanum ion with other atoms in detail.
文摘The Langmuir-Blodgett (LB) technique was used for studying enhanced lumines-cence of Eu (TTA)3 Phen (acceptor) by La (TTA)3 Phen (donor). LB films studied here are:(1) [0. 5% Eu (TTA)3 Phen + 99. 5% La (TTA)3 Phen]: AA = 1: 1; (2) [0. 5%Eu(TTA)3 Phen+99. 5%AA]: AA= 1: 1; (3) La(TTA)3 Phen: AA= 1: 1. These filmscould form stable monolayers at air/water surface. The fluorescence intensity of LB 1 was 65times stronger than that of LB2. This signifies that the luminescence intensity ofEu(TTA)3 Phen could be enhanced by La (TTA)3 Phen clearly. Low angle X-ray diffrac-tog ram of LB1 showed that the film has a period layered structure. To study the intermolec-ular energy transfer, different structures of the multilayer were designed by combining LB2(layer of acceptor) with LB3(layer of donor). The results indicated that the intermolecularenergy transfer occurred in a short-range (<3 nm) and at the position of head-head in Y-typemodel. The influence of the interface on the energy transfer was prominent. The process ofenergy transfer was carried out via the triplet state of TTA.
基金Project supported by National Natural Science Foundation of China(21805143)Natural Science Foundation of Zhejiang Province(LY21B040002)+1 种基金Natural Science Foundation of Ningbo(202003N4110)the K.C.Wong Magna Fund from Ningbo University。
文摘The metathesis reaction between pyrrolidinyl-ethylene fluorenyl lithium salts with in situ prepared cationic rare-earth metal dialkyl species[Ln(CH_(2)SiMe_(3))_(2)(THF)_(x)][BPh_(4)]afford efficiently the corresponding constrained-geometry complexes L^(1)Ln(CH_(2)SiMe_(3))_(2)(L^(1)=FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(1a),Lu(1b),Sc(1c))and L^(2)Ln(CH_(2)SiMe_(3))_(2)(L^(2)=(2,7-di-tert-butyl)FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(2a),Lu(2b),Sc(2c))in good yields.All these complexes were characterized by NMR spectroscopy,and the solid-state molecular structure of yttrium complex 1a was defined with single-crystal X-ray diffraction analysis.The catalytic performance of these complexes towards 2-vinylpyridine polymerization was investigated,where these complexes alone can efficiently promote the polymerization of 2-vinylpyridine giving isotactic poly(2-vinylpyridine).Upon the activation with[Ph_(3)C][B(C_(6)F_(5))_(4)],the yttrium and lutetium complexes also afford isotactic poly(2-vinylpyridine),while the scandium complexes produce syndiotactic poly(2-vinylpyridine).
