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ABSTRACT: In this paper a new cyclometalated iridium(III) coumarin complex, Ir(III)bis(3-(2-benzothiazolyl)coumarinato N,C(4))(acetylacetonate) (Ir(L)2(acac)), was synthesized and characterized. X-ray crystallography demonstrated that the iridium(III) ion is hexacoordinated by two C atoms and two N atoms from 3-(2-benzothiazolyl)coumarinato ligands and two O atoms from acac ligand, displaying distorted octahedral coordination geometry. The Ir(L)2(acac) complex has good thermal stability with less than 2 % weight-reduction occurring at 300 °C, and exhibits strong reddish orange emission. The results shown that Ir(L)2(acac) is useful for fabrication organic light-emitting diodes.
Journal of Fluorescence 03/2013; · 2.11 Impact Factor
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ABSTRACT: Two new mononuclear Cu(I) complexes based on 2-(2'-pyridyl)benzimidazolyl derivative ligand containing hole-transporting carbazole (L), [Cu(L)(DPEphos)](BF4) and [Cu(L)(PPh3)2](BF4), where L=(4-(9H-carbazol-9-yl)phenyl)methyl-2-(2'-pyridyl)benzimidazole; DPEphos=bis[2-(diphenylphosphino)phenyl]ether and PPh3=triphenylphosphine, have been synthesized and characterized on the basis of elemental analysis, (1)H NMR and FT-IR spectra. The structures of the ligand L and the Cu(I) complexes were characterized by single crystal X-ray diffraction. The results reveal that in the Cu(I) complexes the central Cu(I) ions assume the irregular distorted tetrahedral geometry and are tetra-coordinated by the two nitrogen atoms from L ligand and two phosphorus atoms from ancillary ligands. The photophysical properties of the complexes were examined by using UV-vis, photoluminescence spectroscopic analysis. The complexes exhibit weak MLCT absorption bands ranging from 360 to 480nm, and display strong orange phosphorescence in the solid states at room temperature, which is completely quenched in solutions.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2013; 109C:179-185. · 2.10 Impact Factor
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ABSTRACT: Two different types of fluorescent materials containing benzothiazolyl moiety, 2-(benzothiazol-2-yl)phenol derivatives and 3-(benzothiazol-2-yl)coumarin derivatives, were synthesized synchronously using ethyl cyanoacetate, appropriate aromatic aldehyde and 2-aminothiophenol as the starting materials under the catalysis of benzoic acid by one-pot reaction. This method has the advantages of mild reaction conditions, easy processing and low waste. All synthesized compounds were characterized by elemental analysis, IR, (1)H NMR spectra. The structures of 2-(benzothiazol-2-yl)phenol derivatives, 2-(benzothiazol-2-yl)phenol (BTP) and 2-(benzothiazol-2-yl)naphthol (BTN), were determined by X-ray single crystal analysis. The UV-vis absorption and photoluminescence spectra of all synthesized compounds were investigated. The 2-(benzothiazol-2-yl)phenol derivatives exhibit bright green emissions and 3-(benzothiazol-2-yl)coumarin derivatives emit bright blue light in solutions.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 02/2013; 108C:274-279. · 2.10 Impact Factor
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ABSTRACT: The electroluminescent (EL) properties of a new coumarin derivative, 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin (APBC), were investigated. The results show that the EL devices comprised of vacuum vapor-deposited films using the derivative as dopant exhibited blue emission that is identical to the photoluminescence of the thin film. The electroluminescence device of ITO/2-TNATA (5 nm)/NPB (40 nm)/CBP : APBC (1.0 wt%, 30 nm)/PBD (30 nm)/LiF (1 nm)/Al (100 nm) gives a maximum luminous efficiency of 2.3 cd/A at the current density of 20 mA/cm(2), and maximum luminance of 5169 cd/m(2) at 16 V. The external quantum efficiency of the device is 1.85 %.
Journal of Fluorescence 06/2012; 22(6):1509-12. · 2.11 Impact Factor
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ABSTRACT: Series of high molecular weight, readily soluble copolymers were synthesized by Suzuki palladium catalyzed coupling reaction
from 9,9-dioctylfluorene and 2,3-dimethylnaphthopyrazine. The absorption, electrochemical and photoluminescence properties
of the copolymers were studied. The external electrolu-minescence efficiencies in the devices of configuration indium-tin
oxide/polyethylenedioxythiophene-polystyrene sulfonic acid/poly(fluorene-naphthopyrazine)/barium/aluminium varied with the
copolymers composition, and the electroluminescence emission peaks of the copolymers were red-shifted from 530 nm to 584 nm
as 2,3-dimethylnaphthopyrazine mole contents increasing from 0.5% to 30%. The best device performance was observed for devices
fabricated with the copolymer of 2,3-dimethylnathphpyrazine 5% mole contents, showed maximum external quantum efficiency of
1.38% and electroluminescence peaks at around 537 nm.
Polymer Science Series B 04/2012; 52(9):614-620. · 0.56 Impact Factor
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ABSTRACT: Two coumarin derivatives containing electron-transporting benzoxazolyl moiety, 7-(diethylamino)-3-(benzoxazol-2-yl)coumarin (DABOC) and 3-(benzoxazol-2-yl)benzo[5,6]coumarin (BOBC), were synthesized and characterized. The photoluminescence and electroluminescence of the compounds were investigated detailedly. The compounds exhibited strong blue-green emissions in both solution and solid states, but the devices with DABOC as the emitting layer exhibited orange emission and maximum luminous efficiency of 2.8 cd/A and maximum luminance of 8,800 cd/m(2), and the devices with BOBC displayed orange-white emission and maximum luminous efficiency of 0.13 cd/A and maximum luminance of 540 cd/m(2).
Journal of Fluorescence 10/2011; 22(2):631-8. · 2.11 Impact Factor
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Macromolecular Chemistry and Physics 04/2011; 212(11):1193 - 1201. · 2.36 Impact Factor
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ABSTRACT: A new fluorescent chemosensor (A18C6-Ox) in which a monoaza-18-crown-6 is linked to a diaryl-1,3,4-oxadiazole fluorophore by a methylene spacer has been synthesized to evaluate binding interaction with the rare earth ions by means of absorption and emission spectrophotometry. Absorption spectra of A18C6-Ox showed a broad band at 289nm and there was no significant change in the presence of Sc3+, La3+, Pr3+, Sm3+, Gd3+, Tb3+, Yb3+ and Lu3+ except for Ce3+ and Eu3+. From the emission spectral change of A18C6-Ox, interaction of the rare earth ions with A18C6-Ox is very strong. The formation of A18C6-Ox complexing with Sc3+, La3+, Pr3+, Sm3+, Gd3+, Tb3+, Yb3+ and Lu3+ leads to an increase in fluorescence intensity of A18C6-Ox, while Ce3+ and Eu3+ ions interact strongly causing fluorescence quenching of A18C6-Ox. In addition, the optimal complexation stoichiometry of the rare earth ions with A18C6-Ox was investigated by the fluorescent titration.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 01/2011; 78(1):396-400. · 2.10 Impact Factor
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ABSTRACT: An alternating narrow bandgap conjugated copolymer (PICZ-DTBT, E(g) = 1.83 eV) derived from 5,11-di(9-heptadecanyl)indolo[3,2-b]carbazole and 4,7-di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole (DTBT), was prepared by the palladium-catalyzed Suzuki coupling reaction. The resultant polymer absorbs light from 350-690 nm, exhibits two absorbance peaks at around 420 and 570 nm and has good solution processibility and thermal stability. The highest occupied molecular orbital (HOMO) energy level and lowest unoccupied molecular orbital (LUMO) level of the copolymer determined by cyclic voltammetry were about -5.18 and -3.35 eV, respectively. Prototype bulk heterojunction photovoltaic cells from solid-state composite films based on PICZ-DTBT and [6,6]-phenyl-C(71) butyric acid methyl ester (PC(71) BM), show power conversion efficiencies up to 2.4% under 80 mW · cm(-2) illumination (AM1.5) with an open-circuit voltage of V(oc) = 0.75 V, a short current density of J(sc) = 6.02 mA · cm(-2) , and a fill factor of 42%. This indicates that the copolymer PICZ-DTBT is a viable electron donor material for polymeric solar cells.
Macromolecular Rapid Communications 07/2010; 31(14):1287-92. · 4.60 Impact Factor
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ABSTRACT: Two new coumarin derivatives, 7-(N,N'-diethylamino)-3-(4-hydroxyphenyl)-coumarin and 7-(N,N'-diethylamino)-3-(4-bromophenyl)-coumarin, were synthesized successfully. Their structures were verified by single crystal X-ray crystallography. The UV-vis absorption and fluorescence of the compounds were discussed. The compounds exhibit strong blue emission under ultraviolet light excitation. The molecular structures, the lowest energy transitions and the UV-vis spectra of 7-(N,N'-diethylamino)-3-(4-hydroxyphenyl)-coumarin and 7-(N,N'-diethylamino)-3-(4-bromophenyl)-coumarin have been studied with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at B3LYP/6-31G(d) level.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2010; 75(3):1036-42. · 2.10 Impact Factor
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ABSTRACT: The problem of robust Hinf reliable control with exponential stabilization is investigated for time-varying delayed uncertain systems against actuator failure. Based on Lyapunov stability theory, a sufficient condition of the existing of robust reliable controller with exponential stability is given. At the same time, another sufficient condition of the existing of robust reliable controller possessing Hinf performance index is presented. Those conditions are transformed to two linear matrix inequalities (LMIs). The resulting control systems retain robust reliable exponential stability and disturbance attenuation with Hinf-norm bounds despite any outages of actuator.
Intelligent Computation Technology and Automation, 2009. ICICTA '09. Second International Conference on; 11/2009
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ABSTRACT: A new coumarin derivative, 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin, was synthesized and characterized by FT-IR, (1)H NMR, element analysis and single crystal X-ray crystallography. The dihedral angle of benzo[5,6]coumarin ring and phenyl group is 36.15 degrees, and the dihedral angle of phenyl group and anthracene skeleton is 89.37 degrees. The UV-vis absorption and photoluminescence of the compound were discussed. The result shown that the compound exhibits high fluorescence quantum yield (Phi(F)), large Stokes shift and green emission (508 nm). The molecular structure of the compound was optimized using density functional theory (DFT) at B3LYP/6-31G(d) level, and the HOMO and LUMO levels of the compound were deduced.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2009; 75(1):325-9. · 2.10 Impact Factor
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ABSTRACT: Three coumarin derivatives containing benzotriazole moieties, 3-(1-benzotriazolyl)-4-methyl-coumarin (BMC), 3-(1-benzotriazolyl)-4-methyl-benzo[7,8]coumarin (BMBC), and 3-(4-methyl-1-benzotriazolyl)-4-methyl-benzo[7,8]coumarin (MBMBC), were synthesized. Among them, 3-(4-methyl-1-benzotriazolyl)-4-methyl-benzo[7,8]coumarin has been structurally characterized by X-ray crystallography. The cytotoxic effect by Sulforhodamine B (SRB) assay with these compounds against the human hepatocellular carcinoma cell lines (HepG-2) was carried out in vitro. The preliminary results showed that all compounds inhibit HepG-2 growth effectively.
Phosphorus. 10/2009; Sulfur(and Silicon):2655-2663.
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ABSTRACT: Two novel tripodal compounds, tris[2-(7-diethylamino-coumarin-3-carboxamide)ethyl]amine (Tren-C1) and tris[2-(benzo[5,6]coumarin-3-carboxamide)ethyl]amine (Tren-C2), were synthesized and characterized. The UV-vis and fluorescence properties of Tren-C1 and Tren-C2 in solutions were investigated. These two compounds exhibited strong blue emission under ultraviolet light excitation. The maximal fluorescence emission occurred at about the level of 10(-5) mol/L. The chromophore units in the tripodal compounds shown a little interaction in the ground state, while the interactions in the excited state was notable and which leads to a broad and bathochromic shift of the emission bands.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 08/2009; 73(1):168-73. · 2.10 Impact Factor
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ABSTRACT: According to energy conversation and thermodynamics theory, the transfer function model of evaporation source in vacuum coating can be built up. With respect to the problem that parameters of evaporation source change greatly, the conventional PID control hardly ensures stability of system, manpower intervention is largely need during coating process, and the quality of coating film is unstable, this paper suggests a method using the variables of deviation and deviation changes to distinguish closed-loop system stability. Based on this, a control method of the PI parameters self-tuning real-time online by fuzzy is introduced. The simulation results show that the evaporation source control method of the PI parameters self-tuning real-time online by fuzzy has well control effectiveness in evaporation source closed-loop system stability.
Control and Decision Conference, 2009. CCDC '09. Chinese; 07/2009
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ABSTRACT: This paper proposes an adaptive protection scheme which has been developed through the analysis of short circuits in transmission lines. The method assumes a different protection pattern depending upon the distance between the fault position and the location of any protection devices. An adaptive threshold dependent upon the load on the system is used for initiation of the over-current protection routines. The adaptive quick-break current protection adopts a different threshold current according to the system mode and the type of short circuit. It is shown that the selectivity and reliability of the power system can be ensured, and sensitivity improved.
Control and Decision Conference, 2009. CCDC '09. Chinese; 07/2009
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ABSTRACT: The problem of robust H<sub>infin</sub> reliable control is investigated for time-varying delayed uncertain systems against actuator failures. In the considered system, the parameter uncertainty satisfies a generalized matching condition, and the time-varying delay is bounded and its derivative is unbounded. All the outputs of the actuator failures are assumed to be zero. Based on Lyapunov-Razumkhin stability theory, a sufficient condition of the existence of robust reliable controller which enables the closed-loop system to possess H<sub>infin</sub> performance index is given. At the same time, a designing approach of memoryless state-feedback controller is presented. The sufficient condition is represented by linear matrix inequalities (LMIs) and has relevance to time delay. The resultant control systems retain asymptotic stability and disturbance attenuation with H<sub>infin</sub> -norm bounds irrespective of any outages within a prespecified subset of actuators. A numerical example shows the validity of the proposed design method.
Control and Decision Conference, 2008. CCDC 2008. Chinese; 08/2008
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ABSTRACT: The structure of 7-(N,N'-diethylamino)-coumarin-3-carboxylic acid (DCCA) was verified by single crystal X-ray crystallography. The UV-vis absorption and fluorescence of DCCA were discussed. The compound exhibits strong blue emission under ultraviolet light excitation. The molecular structure of DCCA was optimized using density function theory (DFT) at B3LYP/6-31G level, showing that the optimized geometers parameters are in good agreement with experiment data. In addition, the HOMO and LUMO levels of DCCA were deduced.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 05/2008; 69(4):1136-9. · 2.10 Impact Factor
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ABSTRACT: A novel Tb(III) complex TbL (L=tris[2-(2-carboxyphenoxy)ethyl]amine, H3L) was synthesized and characterized by means of elemental analyses, IR spectra, thermal analyses, and molar conductivity measurement. The photoluminescent properties of the complex were investigated. In addition, PVK doping Tb(III) complex was fabricated as the emissive layer by spin-coating and its electroluminescent properties were studied, in which the structure of the device was ITO (indium tin oxide)/PVK (polyvinylcarbazole)/PVK: TbL/PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole)/LiF/Al. It was indicated that pure green and narrow bandwidth emission at 545nm from photoluminescence of TbL complex film and the organic electroluminescent device is the characteristic emission of Tb(III) ion, and the electroluminescence spectrum of the device was very similar to that of the photoluminescence of TbL complex film. The lowest triplet level of the ligand was calculated from the phosphorescence spectrum of GdL in N,N-dimethyl formamide (DMF) dilute solution determined at 77K, and the energy transfer mechanisms in TbL complex were discussed.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2008; 69(2):654-8. · 2.10 Impact Factor
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ABSTRACT: Two novel triethylene-glycol dicoumarin-3-carboxylates were synthesized and characterized by element analysis, (1)H NMR, FT-IR and UV-vis absorption spectra. The photoluminescent behaviors of triethylene-glycol dibenzo[5,6]coumarin-3-carboxylate doped in PMMA were discussed. These compounds exhibit strong blue emission under ultraviolet light excitation. Compared to coumarin-3-triethylene glycol diester, the absorption and emission spectra of benzo[5,6]coumarin-3-triethylene glycol diester was bathochromically shifted due to the larger conjugation of benzene moiety. These derivatives have potential possible to explore organic electroluminescent materials.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 12/2007; 68(3):725-7. · 2.10 Impact Factor
