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1.
Toby D. M. Bell Dr. Sheryll Yap Chintan H. Jani Sheshanath V. Bhosale Dr. Johan Hofkens Prof. Frans C. De Schryver Prof. Steven J. Langford Prof. Kenneth P. Ghiggino Prof. 《化学:亚洲杂志》2009,4(10):1542-1550
The synthesis and photophysics of two new aminopropenyl naphthalene diimide (SANDI) dyes are reported. A general and convenient method for the synthesis of the precursor mono‐, di‐, and tetrabrominated 1,4,5,8‐naphthalene tetracarboxylic dianhydrides is described. The two core‐substituted SANDIs exhibit many of the photophysical properties required for fluorescence labeling applications including high photostability and high fluorescence quantum yields (>0.5) in the visible region of the spectrum. The emission wavelength is sensitive to the number of substituents on the NDI core, and the fluorescence decay times are in the range of ~8–12 ns for both compounds in the solvents investigated. Preliminary fluorescence emission data from single molecules of the compounds embedded in poly(methyl methacrylate) films are also reported and show that single molecules have very low yields of photobleaching, particularly the di‐substituted system. Furthermore, only a small proportion (<10 %) of the single molecules studied display fluorescence intermittencies or “blinks” in their photon trajectory. The compounds appear to be excellent candidates for applications at the single molecule level, for example, as FRET labels. 相似文献
2.
Jancarlo Gómez-Vega Ramón Alfonso Moreno-Corral Hisila Santacruz Ortega David Octavio Corona-Martínez Herbert Höpfl Rogerio R. Sotelo-Mundo 《Supramolecular chemistry》2019,31(5):322-335
Two bis-urea type receptors were synthesized containing a polyether bridge and two 4-nitrophenyl groups as chromogenic units, R1 and R2. Molecular recognition studies of receptors towards different tetraalkylammonium and alkali metal salts were carried out in DMSO by UV-Vis and 1H-NMR spectroscopy. The receptors were found to have high affinity for diverse anions and ion-pairs, showing the highest affinities towards the tetramethylammonium and sodium salts. The cation binding ability of the receptors was evidenced by means 1H NMR, mass spectrometric ESI+ studies and the crystal structures of some precursors. Additionally, the molecular modelling at the DFT level of the tetramethylammonium acetate complexes illustrates the potential ion-pair binding ability of the receptors: the anion is recognized through strong hydrogen bonds from the NH─ groups from the two urea sites, while the cation is bound by a combination of cation─π, C-H···O and C-H···π interactions. 相似文献
3.
Nicola Hoogen Oskar Nuyken 《Journal of polymer science. Part A, Polymer chemistry》2000,38(10):1903-1910
The synthesis and photoreactions of polyesters containing the photolabile triazene group (Ph NN NR2) as well as photocrosslinkable units based on substituted cinnamylidene malonyl moieties are reported. The polyesters were obtained by reacting a triazene containing difunctional alcohol with different substituted cinnamylidene malonic acid dichlorides. Irradiation at λ > 395 nm enables selective photocrosslinking of the cinnamylidene malonyl ester units via [2+2]π‐cycloaddition without affecting the triazene units. The photocrosslinking reaction of the triazene containing polyesters as well as triazene‐free reference polyesters were investigated by UV and IR spectroscopy. After selective photocrosslinking the irradiated polymers became insoluble and no longer exhibited a Tg below decomposition temperature. The crosslinked triazene containing polyesters show strong absorption at λ = 308 nm and are therefore interesting candidates for applications using XeCl excimer laser ablation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1903–1910, 2000 相似文献
4.
利用聚甲基氢硅氧烷(PHMS)与4-(β-羟基-γ-烯丙氧)丙氧基-2-羟基二苯甲酮(MUV-O)、α-烯基聚醚(F6)的硅氢化加成反应,合成了一种新型聚醚-二苯甲酮衍生物侧基聚硅氧烷PE-PUVSi,用红外光谱(IR)、紫外光谱(UV)、核磁共振氢谱(1H-NMR)以及原子力显微镜(AFM)等仪器对产物的结构和成膜形态进行了研究。结果表明,新合成的PE-PUVSi对波长为243.6、289.2、325.0nm的紫外光有强吸收作用。在纤维及单晶硅表面,PE-PUVSi均可成膜。但宏观上平滑的PE-PUVSi膜,微观上实则呈非均一、相分离结构,其中UV侧基以纤细尖峰分布在聚硅氧烷膜表面,而亲水性聚醚基团则卷曲堆积成峰包。 相似文献
5.
Ying Zhao Emma Rostal Sørensen Thomas Toft Lindkvist Dr. Christina Kjær Prof. Mogens Brøndsted Nielsen Prof. Li Chen Prof. Steen Brøndsted Nielsen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(42):10875-10882
When ionic dyes are close together, the internal Coulomb interaction may affect their photophysics and the energy-transfer efficiency. To explore this, we have prepared triangular architectures of three rhodamines connected to a central triethynylbenzene unit (1,3,5-tris(buta-1,3-diyn-1-yl)benzene) based on acetylenic coupling reactions and measured fluorescence spectra of the isolated, triply charged ions in vacuo. We find from comparisons with previously reported monomer and dimer spectra that while polarization of the π-system causes redshifted emission, the separation between the rhodamines is too large for a Stark shift. This picture is supported by electrostatic calculations on model systems composed of three linear and polarizable ionic dyes in D3h configuration: The electric field that each dye experiences from the other two is too small to induce a dipole moment, both in the ground and the excited state. In the case of heterotrimers that contain either two rhodamine 575 (R575) and one R640 or one R575 and two R640, emission is almost purely from R640 although the polarization of the π-system expectedly diminishes the dipole-dipole interaction. 相似文献
6.
WANG Ming LI Ying XIE ZhiYuan & WANG LiXiang State Key Laboratory of Polymer Physics Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China 《中国科学B辑(英文版)》2011,(4)
A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-... 相似文献
7.
A series of tetracene-doped anthracene crystals with different doping concentrations (the highest molar ratio 100 1) are grown
from solution. Crystal structures and optical characteristics of the above mixed crystals are investigated at room temperature.
By changing the doping concentrations, the fluorescence can be adjusted from blue-green to green and even to yellow-green.
The emission spectra of anthracene/tetracene (An/Te) mixed crystals reveal the sensitized fluorescence of tetracene and the
partial quenching of anthracene emission. The data of transient photoluminescence (PL) decays illustrate that in An/Te mixed
crystals, the decay of anthracene becomes faster, while the PL lifetime of tetracene is longer than that of the tetracene
single crystals. All above experimental results suggest that there is excitation energy transfer from anthracene to tetracene
in the mixed crystals.
Supported by the National Natural Science Foundation of China (Grant No. 5057 3039) and the National Key Basic Research and
Development Program of China (Grant No. 2006CB806200) 相似文献
8.
<正>A brominated hyperbranched polyether has been synthesized from cyanuric chloride and sodium salt of tetrabromobisphenol-A by an A_2+B_3 approach.The synthesized polyether was characterized by ~1H-NMR,~(13)C-NMR,UV, FTIR spectroscopy and X-ray diffraction studies,measurements of solution viscosity,molecular weight and solubility and elemental and thermogravimetric analyses.The flame retardancy of the synthesized polyether and its blends with commercially available plasticized poly(vinyl chloride)(PVC) and low density polyethylene(LDPE) was investigated by measurements of limiting oxygen index(LOI) value and thermogravimetric analysis.The properties are compared with a non-halogenated similar type of bisphenol-A based aromatic polyether after blending at different dose levels with the same base polymers.The LOI values of these blends indicated that these hyperbranched polyethers acted as flame retardant additives,and antimony trioxide had prominent synergistic effect with the bromo hyperbranched polyether for the above base polymers,and an increment of 4 to 6 units in LOI values was observed. 相似文献
9.
合成了基于分子内荧光能量转移的蒽(An)-四苯基卟啉(TPP)双发色团碘荧光探针1.由于An的荧光光谱与TPP的S吸收带具有较好的重叠,供体An与受体TPP之间可以发生有效的分子内荧光能量转移,以An的最大吸收波长作为激发波长时,由于分子内荧光能量转移,受体TPP发出荧光.当碘与探针分子中的识别基团An作用时,导致探针分子的荧光转导基团TPP荧光淬灭.与An、TPP和An+TPP混合物作敏感材料相比,将探针1固定在PVC膜中制备的敏感膜对碘选择性高、灵敏度好.另外,敏感膜具有很好的重现性、可逆性和稳定性,响应时间小于60S.除Cr2O7^2-和MnO4^-外,食品中常见的无机离子和可能存在的干扰物质不影响碘的测定.在最优条件下,传感器的线性范围为2.04×10^-6-2.36×10^-2mol/L,检出限为3.30×10^-8mol/L.本方法应用于加碘食盐中碘含量的测定,结果满意. 相似文献
10.
Ming Wang Hui Tong Yanxiang Cheng Zhiyuan Xie Lixiang Wang Xiabin Jing Fosong Wang 《Journal of polymer science. Part A, Polymer chemistry》2010,48(9):1990-1999
Novel conjugated copolymers based on 9,9‐dioctylfluorene and bisphenazine (BP) were synthesized by Suzuki polymerization. Energy transfer from the conjugated main chain to the BP moieties was observed. Full energy transfer was achieved when the molar content of the bisphenazine was 20% (20BPPF) in toluene solution. The similar phenomena were observed even for 1% bisphenazine content copolymer (1BPPF) in film. The lowest occupied molecular orbital (LUMO) energy levels (?3.06 eV) of the copolymers were lower than that of the polyfluorene homopolymer (PFO; ?2.65 eV), indicating that the introduction of the BP unit was benefit to electron injection. Single‐layer electroluminescent devices (ITO/PEDOT:PSS/polymer/LiF/Al) were fabricated to investigate their electroluminescence (EL) performances. The maximum brightness and current efficiency of all BPPF copolymers surpassed the PFO homopolymer. The best single‐layer device was based on 5BPPF, with a maximum brightness of 1532 cd/m2 and current efficiency of 1.09 cd/A. Much higher efficiency could be achieved for multilayer EL devices of 5BPPF (ITO/PEDOT:PSS/PVK/polymer/TPBI/LiF/Al), which showed a maximum current efficiency of 10.01 cd/A. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1990–1999, 2010 相似文献
11.
Alex Man-Hei Yip Justin Shum Dr. Hua-Wei Liu Huipeng Zhou Meiqi Jia Niu Niu Yongxin Li Prof. Cong Yu Prof. Kenneth Kam-Wing Lo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(38):8970-8974
This communication reports novel luminescent rhenium(I)–polypyridine complexes appended with a perylene diimide (PDI) or benzoperylene monoimide (BPMI) moiety through a non-conjugated linker. The photophysical and photochemical properties originating from the interactions of the metal polypyridine and perylene units were exploited to afford new cellular reagents with thiol-sensing capability and excellent photocytotoxic activity. 相似文献
12.
13.
Multi-arm star polystyrenes with hyperbranched poly(3-ethyl-3-oxetanemethanol) (PEOM, 3) core were synthesized by atom transfer radical polymerization (ATRP) method. The structures of polymers were confirmed by FT-IR and 1H NMR. GPC results showed that the resultant polymers had relatively low polydispersity indices (PD = 1.47-2.03). DSC analysis indicated that polystyrene star polymers had a glass transition temperature (Tg = 42.2-91.5 °C) that changed with the amount of the polystyrene in the polymers. In addition, the aggregation behavior of the multi-arm star polystyrenes in a selective solvent (THF/cyclohexane) was probed with polystyrene arms that encapsulated in the aggregates and PEOM cores hidden in the center of the micelles. 相似文献
14.
Tzu-Chau Lin Cheng-Sheng Hsu Chia-Ling Hu Yong-Fu Chen Wei-Je Huang 《Tetrahedron letters》2009,50(2):182-6753
A new multipolar fluorophore derived from triphenylamine as the core with diphenylaminoindenofluorenyl moieties incorporated at the peripheral positions has been synthesized and experimentally shown to possess strong two-photon absorptivities in near-IR region and intense upconverted visible emission under the irradiation of femtosecond laser pulses. 相似文献
15.
Photoinduced electron-transfer system of anthracene-N,N-di-ethylaniline (DEA) was studied in the oil in water (O/W) mi-croemulsions formed by SDS (sodium dodecyl sulfate),BA (benzyl alcohol) and H2O.The time-resolved fluorescence study showed that the fluorescence quenching of the excited anthracene by DEA occurs at the interface of the O/W mi-croemulsions.Besides as the quencher of the excited anthracene,N,N-diethylaniline could act as a cosurfactant to change the structures of the microemulsions,just as BA did.The quenching rate constants for the different structures of the system were determined. 相似文献
16.
The hyperbranched and the linear polyethers were prepared by one-pot nucleophilic displacement polymerization technique using cyanuric chloride and aromatic diol as reported earlier. The physical, thermal, dielectric and chemical properties of the hyperbranched polyether and its linear analog have been studied. The amorphous character of both the polyethers was observed in XRD study. The solubility studies showed that the hyperbranched polyether has relatively higher solubility in different solvents compared to its linear analog. The thermal properties of both polymers have been studied by thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. The chemical resistance tests indicated that both polyethers are very good chemical resistances except in dilute aqueous alkali solution. The dielectric properties such as dielectric constant and loss factor for both polyethers have also been studied with respect to changes of frequency (50-500 kHz) and temperature (303-343 K). 相似文献
17.
Fluorescence resonance energy transfer by quencher adsorption into hydrogels containing fluorophores
Kaori Okawa Takashi Miyata Tadashi Uragami 《Journal of Polymer Science.Polymer Physics》2006,44(22):3245-3252
We synthesized anionic hydrogels containing fluorophores and investigated the adsorption of a cationic quencher having an amino group into hydrogels by fluorescence resonance energy transfer (FRET). FRET from the fluorophore to the quencher in hydrogels was examined by fluorescence intensity and fluorescence decay using a fluorescence spectrophotometer and femtosecond laser spectroscopy. The fluorescence intensity of the fluorophore‐containing hydrogels decreased rapidly with increasing amounts of adsorbed cationic quencher. The fluorescence emission of the fluorophore in the quencher‐adsorbed hydrogels containing fluorophores decayed more rapidly than that of the original hydrogels. The aforementioned result indicates that the fluorescence of the fluorophore‐containing hydrogels is quenched due to FRET from the fluorophore to the quencher as the cationic quenchers can approach the fluorophores in hydrogels by electrostatic interactions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3245–3252, 2006 相似文献
18.
Dr. Yuichi Kitagawa Ayu Naito Kota Aikawa Kaori Shima Dr. Sunao Shoji Dr. Koji Fushimi Prof. Yasuchika Hasegawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(16):e202104401
A spin-selective tribo-chemical reaction using a dinuclear lanthanide complex is demonstrated for the first time. The dinuclear complex is composed of two EuIII ions, hexafluoroacetylacetonato ligands, and anthracene-based phosphine oxide bridges. Single-crystal analysis revealed a face-to-face-type anthracene dimer structure in the dinuclear EuIII complex. Mechanical stimulus on the dinuclear EuIII complex induced selective formation of oxidized anthracene. The tribo-chemical reaction is based on a characteristic energy-transfer pathway for the selective formation of an excited triplet state. 相似文献
19.
Mariusz Tasior Dr. Daniel T. Gryko Prof. Dominika J. Pielacińska Alberto Zanelli Dr. Lucia Flamigni Dr. 《化学:亚洲杂志》2010,5(1):130-140
Four dyads comprised of corrole and coumarin units have been synthesised. Three coumarincarboxaldehydes were synthesized and transformed into the corresponding trans‐A2B‐corroles by reaction with 5‐(pentafluorophenyl)dipyrromethane. It has been proven that this type of direct condensation can lead to the corresponding corroles in moderate yields. The reaction of hydroxybenzaldehydes with vinylphosphonium salts has been identified as the most general method for the preparation of formyl‐coumarins with various patterns of substituents. The dyad consisting of ketobiscoumarin and corrole was synthesized by Sonogashira coupling. Spectroscopic and photophysical investigations revealed that there is an efficient energy transfer from the coumarin moiety to corrole in all four dyads. Energy transfer can be clearly ascribed to a dipole–dipole mechanism (Förster) for all dyads that contain luminescent coumarins and to an electron exchange mechanism (Dexter) for the dyad with the non‐luminescent one. In the case of the dyad that bears coumarin with a hydroxy group at position 5, an electron‐transfer was detected from corrole to coumarin. The latter process is possible because of the suitably low reduction potential of coumarins of this type. 相似文献