Synthesis and photophysics of novel 8-hydroxyquinoline aluminum metal dye with hole transfer groups

A novel luminescent dye metal complex, (CZHQ)3Al, with 8-hydroxyquinoline aluminum and hole-transporting carbazole units was designed and synthesized. The (CZHQ)3Al optical properties were carefully investigated by UV-vis absorption and fluorescence spectra in diluent solution. The results showed that the luminescent quantum yield of (CZHQ)3Al was 0.62 in DMSO and it emitted red-light with the band gap of 2.89 eV estimated from the onset absorption. In addition, the light-emission of (CZHQ)3Al can be quenched by electron acceptor (dimethylterephalate), where the process followed the Stern-Volmer equation. However, the fluorescent intensities of (CZHQ)3Al were slowly increased with the addition of electron donor (N,N-dimethylaniline). Furthermore, the molecular interactions of (CZHQ)3Al with fullerene (C60) and carbon nanotubes (CNTs) were also respectively investigated, which indicated the metal dye can be used as new fluorescent probe.     

4-二氰乙烯基-N,N-二甲基苯胺与不同表面活性剂的相互作用

用光谱法研究了荧光分子4-二氰乙烯基-N,N-二甲基苯胺(DCVA)与十二烷基硫酸钠(SDS)、聚氧乙烯(23)月桂醚(BRIJ35)、十二烷基三甲溴化铵(DTAB)胶束间的相互作用.与在水中相比,在上述3类表面活性剂溶液中探针的荧光强度分别增加到3.3、5.4和5.1倍;最大发射波长随表面活性剂浓度的增加分别蓝移了5、11和9nm.由此可知,DCVA在DTAB和BRIJ35胶束中所处微环境的极性相似,而在SDS胶束中DCVA所处微环境的极性较大.通过DCVA在3种表面活性剂溶液中的荧光强度,计算出了DCVA与其胶束的结合常数分别为1.7×10³、1.4×10³和8.8×10².     

Synthesis and photophysics of novel 8-hydroxyquinoline aluminum metal complex with 1,3,4-oxadiazole units

A novel luminescent metal complex, (OXHQ)3Al, with 8-hydroxyquinoline aluminum and electron-transporting 1,3,4-oxadiazole unit was designed and synthesized. The photophysical processes were investigated by UV-vis absorption and fluorescence emission spectra in diluent solution. The results showed that the luminescence quantum yield of (OXHQ)3Al was 0.67 in DMSO and it emitted blue light with the band gap of 3.13 eV estimated from the onset absorption. In addition, the light-emitting of (OXHQ)3Al can be quenched by electron acceptor (dimethylterephalate), where the processes followed the Stern-Volmer equation. However, with the addition of electron donor (N,N-dimethylaniline) fluorescent intensity of (OXHQ)3Al was increased and emission peak was lightly blue-shift. Furthermore, the molecular interactions of (OXHQ)3Al with fullerene (C60) or carbon nanotubes (CNTs) were also carefully investigated.     

Synthesis and photophysics of novel 8-hydroxyquinoline aluminum metal complex with fluorene units

A novel luminescent metal complex, (MQPF)3Al2, with 8-hydroxyquinoline aluminum and 9,9-diphenylfluorene was synthesized. The optical properties were investigated by UV-vis absorption and fluorescence emission spectra. The results showed that the luminescence quantum yield of (MQPF)3Al2 was 0.612 in THF and it emitted red light with the band gap of 3.18 eV estimated from the onset absorption. The emission spectra exhibited obvious solvent effect. With the increase of polarity of solvents the fluorescence spectra changed obviously and appeared blue shift about 60 nm at room temperature. In addition, the light-emitting can be quenched by both electron donor (N,N-dimethylaniline) and electron acceptor (Fullerene), where the processes followed the Stern-Volmer equation. However, when adding 1,4-dicyanobenzene (DCB) which was a stronger electron acceptor to the solution of (MQPF)3Al2, the fluorescent intensity was increased.     

A μ3-OH- bridged two-dimensional zinc(Ⅱ) coordination polymer based on an anthryl ligand：Synthesis, characterization and luminescent properties

A two-dimensional (2D) 3,3,3,4,5,5,6-connected ZnⅡ coordination compound [Zn5(L)2(OH)6]∞ (L=9,10-dioxo-9,10-dihydroanthracene-1,8-dicarboxylate) has been synthesized and characterized by IR, elemental analysis, X-ray powder diffraction and single crystal X-ray diffraction analysis. Moreover, the luminescent properties of the ligand and corresponding compound have been briefly investigated.     

Fluorescence Sensor with A New ON1–OFF–ON2 Switching Mechanism Using the Excited State Intermolecular Proton Transfer Reaction of An Anthracene‐diurea Compound

A new photoreaction mechanism of “Three‐state molecular switch” fluorescence sensor based on ON¹‐OFF‐ON² sequence was achieved by anthracene‐diurea compound, which was designed using two phenylurea groups and one anthracene, 9,10BtDSPUA. Photochemical properties of 9,10BtDSPUA and interaction between 9,10BtDSPUA and anion were investigated in detail by absorption, ¹H NMR, fluorescence, and fluorescence decay measurements. While the fluorescence of 9,10BtDSPUA in DMSO (ON¹) was quenched in the presence of low concentration of acetate anion (OFF), fluorescence enhancement occurred by the addition of high concentration of acetate anion (ON²). This compound forms complex with acetate anion through hydrogen bonding interaction in the ground state resulted in tautomer formation by excited state intermolecular proton transfer (ESIPT) on irradiation. Whereas single coordination of acetate anion to anthracene‐diurea compound may cause fluorescence quenching, full coordination may cause fluorescence enhancement due to suppressing ESIPT. This suppressing ESIPT was occurred by electron‐donating resonance effect between two urea moieties. This study is the first example of ON¹‐OFF‐ON² fluorescence sensor for concentration detection of acetate anion.     

一种新的D-π-A型异佛尔酮衍生物的合成及性质

通过Knoevenagel反应,合成了具有D-π-A结构的异佛尔酮衍生物（2-(3-(4-(双(2-(2-硝基苯氧基)乙基)氨基)苯乙烯基)-5,5-二甲基环-2-烯-1-亚基)丙二腈）,产率为80.7%,用红外光谱、核磁共振氢谱对化合物进行了表征。 初步研究了该化合物的光学和电化学性质及热稳定性,结果表明,该化合物有较好的光学性质和热稳定性。为寻找新的发光材料进行了有益的探索。     

Synthesis, characterization and photophysical processes of fluorene derivative containing naphthalene nucleus

A novel luminescent compound, 9,9-bis[4'-(beta-naphthyl-methacrylate)phenyl]fluorene (F-NMAP) is synthesized by Heck reaction of beta-naphthyl methacrylic ester (NMAE) and 9,9-bis(4'-iodophenyl)-fluorene (BIPF). The structure is characterized by MS, 1H NMR, IR, and UV-vis spectroscopy. The photophysical processes of F-NMAP have been carefully investigated by UV-vis absorption and fluorescence spectra. The results show that the compound emits blue and blue-violet light. The luminescence quantum yield is 0.652 in ethanol and the emission spectra exhibit obvious solvent effect. With the increase in polarity of solvents, the fluorescence spectra change obviously and appear blue shift at room temperature. The light emitting can be quenched by both electron donor, N,N-dimethylaniline (DMA), and electron acceptor, dimethylterephthalate (DMTP). On adding gradually, DMA or DMTP into the solution of F-NMAP, the emission intensities of fluorescence are unusually increased. But when the concentration of DMA or DMTP goes beyond a certain scope, the emission intensities of fluorescence are gradually decreased. Simultaneously, the maximum emission peaks of F-NMAP-added DMA are blue-shifted and the maximum emission peaks of F-NMAP-added DMTP are red-shifted, respectively. Moreover, interactions between F-NMAP and fullerene (C60), or carbon nanotubes (CNTs) are also studied by fluorescent quenching where the processes follow the Stern-Volmer equation.     

Synthesis and photophysical processes of 9-bromo-10-naphthalen-2-yl-anthracene

A novel luminescent compound, 9-bromo-10-naphthalen-2-yl-anthracene (BNA) is synthesized by Suzuki Cross-coupling reaction of 9-bromo-anthracene and naphthalene-2-boronic acid. The structure is characterized by (1)H NMR, IR and UV-vis spectroscopy. The photophysical processes of 9-bromo-10-naphthalen-2-yl-anthracene have been carefully investigated by UV-vis absorption and fluorescence spectra. The results show that the compound emits blue and blue-violet light. The emission spectra exhibit obvious solvent effect. With the difference in polarity of solvents, The emission spectra is not only slightly blue shift with the increase of the solvent polarity but also change on the intensity of fluorescence at room temperature .The light emitting can be quenched by electron donor, N,N-dimethylaniline (DMA). On adding gradually DMA into the solution of BNA, the emission intensities of fluorescence are gradually decreased. The quenching effect follows the Stern-Volmer equation.     

Marcus theory of outer-sphere heterogeneous electron transfer reactions: dependence of the standard electrochemical rate constant on the hydrodynamic radius from high precision measurements of the oxidation of anthracene and its derivatives in nonaqueous solvents using the high-speed channel electrode

The validity of Marcus theory for outer-sphere heterogeneous electron transfer for the electro-oxidation of a range of anthracene derivatives in alkyl cyanide solvents is investigated. The precision measurement of these fast electron transfers (k(0) >or= 1 cm s(-1)) is achieved by use of the high-speed channel electrode and, where necessary, fast-scan cyclic voltammetry. First, the solvent effect on the rate of electron transfer is studied by considering the first oxidation wave of 9,10-diphenylanthracene in the alkyl cyanide solvents: acetonitrile, propionitrile, butyronitrile, and valeronitrile. Second, the variation of k(0) for a series of substituted anthracenes is investigated by analyzing the voltammetric response of the one-electron oxidations of 9-phenylanthracene, 9,10-dichloroanthracene, 9-chloroanthracene, 9,10-dicyanoanthracene, 9-cyanoanthracene, 9-nitroanthracene, 9,10-diphenylanthracene, and anthracene in acetonitrile. It is shown that the rate of electron transfer of a single compound in different alkyl cyanides is determined by the longitudinal dielectric relaxation properties of the solvent, while differences in rate between the substituted anthracenes in acetonitrile can be quantitatively rationalized by considering their relative hydrodynamic radii. This makes possible the accurate prediction of electron-transfer rates for a molecule by interpolation of rate constants known for related molecules.     

Synthesis of N‐[(tert‐Butoxy)carbonyl]‐3‐(9,10‐dihydro‐9‐oxoacridin‐2‐yl)‐L‐alanine,a New Fluorescent Amino Acid Derivative

A simple synthesis of a new, highly fluorescent amino acid and of its protected derivative useful in peptide studies is described. The obtained derivative, N‐[(tert‐butoxy)carbonyl]‐3‐(9,10‐dihydro‐9‐oxoacridin‐2‐yl)‐L ‐alanine ( 6 ), shows intense long‐wave absorption (above 360 nm) and emission (above 400 nm). The quantum yield of fluorescence of the investigated compound is very high, so it can serve as a sensitive analytical probe useful, e.g., in analysis of peptide conformations.     

9,10-Dichlorooctafluoroanthracene as a building block for n-type organic semiconductors

9,10-Dichlorooctafluoroanthracene (1) was synthesized from commercially available tetrafluorophthalic acid by an optimized solution-phase route. To establish 1 as a synthon for n-type organic semiconductors, the compound was reacted with phenylboronic acid under modified Suzuki-Miyaura coupling conditions to generate octafluoro-9,10-diphenylanthracene (7) in high yield. Cyclic voltammetry and X-ray crystallography indicate that 7 has a stabilized LUMO energy level and exhibits extended pi stacking, which should lead to efficient electron transport in solid-state devices. 1,2,3,4,5,6,7,8-Octafluoroanthracene (2) was also synthesized as a potential n-type building block, but suitable C-C coupling conditions for this compound were not found, and 2 could not be converted into 9,10-dibromooctafluoroanthracene or octafluoro-9,10-diiodoanthracene.     

The influence of charge-transfer interactions on solid and cholesteric liquid crystalline mixtures of cholesteryl anthraquinone-2-carboxylate and cholesteryl 9,10-dimethoxyanthracene-2-carboxylate

The phase behaviour of 3beta-cholesteryl 9,10-anthraquinone-2-carboxylate (CAQ, an excellent electron acceptor) and 3beta-cholesteryl 9,10-dimethoxyanthracene-2-carboxylate (CMAQ, an excellent electron donor) have been investigated neat and as mixtures by a variety of techniques. Both molecules form thermotropic cholesteric phases. UV-Vis absorption spectra of CAQ:CMAQ mixtures provide strong evidence for the formation of charge-transfer (CT) complexes in the solid state. DSC thermograms of the mixtures reveal several transitions, only some of which are observable by optical microscopy. The mesophase range of CAQ is increased by c. 40 upon addition of as little as 10 wt% of CMAQ as a consequence of increased attractive forces in the CT complexes. X-ray powder diffraction patterns confirm that CAQ forms different crystalline phases upon being cooled from the mesophase and by recrystallization from solvents. The 5:5 mixture can be supercooled to a glass from its cholesteric phase. Some of the phase behaviour of the CAQ:CMAQ mixtures is explained with a model that includes selective crystallization of the two components into eutectics from supercooled liquid crystalline matrices.     

Principles of Aggregation‐Induced Emission: Design of Deactivation Pathways for Advanced AIEgens and Applications

Twenty years ago, the concept of aggregation‐induced emission (AIE) was proposed, and this unique luminescent property has attracted scientific interest ever since. However, AIE denominates only the phenomenon, while the details of its underlying guiding principles remain to be elucidated. This minireview discusses the basic principles of AIE based on our previous mechanistic study of the photophysical behavior of 9,10‐bis(N,N‐dialkylamino)anthracene ( BDAA ) and the corresponding mechanistic analysis by quantum chemical calculations. BDAA comprises an anthracene core and small electron donors, which allows the quantum chemical aspects of AIE to be discussed. The key factor for AIE is the control over the non‐radiative decay (deactivation) pathway, which can be visualized by considering the conical intersection (CI) on a potential energy surface. Controlling the conical intersection (CI) on the potential energy surface enables the separate formation of fluorescent (CI:high) and non‐fluorescent (CI:low) molecules [control of conical intersection accessibility ( CCIA )]. The novelty and originality of AIE in the field of photochemistry lies in the creation of functionality by design and in the active control over deactivation pathways. Moreover, we provide a new design strategy for AIE luminogens (AIEgens) and discuss selected examples.     

Blue-emissive upconversion nanoparticles for low-power-excited bioimaging in vivo

Water-soluble upconversion luminescent (UCL) nanoparticles based on triplet-triplet annihilation (TTA) were successfully prepared by coloading sensitizer (octaethylporphyrin Pd complex) and annihilator (9,10-diphenylanthracene) into silica nanoparticles. The upconversion luminescence quantum yield of the nanoparticles can be as high as 4.5% in aqueous solution. As determined by continuous kinetic scan, the nanoparticles have excellent photostability. Such TTA-based upconversion nanoparticles show low cytotoxicity and were successfully used to label living cells with very high signal-to-noise ratio. UCL imaging with the nanoparticles as probe is capable of completely eliminating background fluorescence from either endogenous fluorophores of biological sample or the colabeled fluorescent probe. In particular, such blue-emissive upconversion nanoparticles were successfully applied in lymph node imaging in vivo of living mouse with excellent signal-to-noise ratio (>25), upon low-power density excitation of continuous-wave 532 laser (8.5 mW cm(-2)). Such high-contrast and low-power excited bioimaging in vivo with a blue-emissive upconversion nanoparticle as probe may extend the arsenal of currently available luminescent bioimaging in vitro and in vivo.     

Experimental and theoretical study of a new carbazole derivative having terminal benzimidazole rings

A novel intramolecular donor–acceptor compound has been synthesized and characterized. This compound was a symmetrical A–π–D–π–A type molecule containing two benzimidazole rings as two electron acceptors (A) and an N-ethylcarbazole group as electron donors (D). The absorption and emission spectra of the compound were determined by experimental methods in solution and were computed by using the density functional theory (DFT) and the time-dependent density functional theory (TDDFT) in gas phase and in chloroform solution. The calculated absorption and emission wavelengths were in good agreement with the experimental ones. The fluorescence quantum yields and fluorescence lifetimes of the compound in several solvents have been studied by means of steady state and time resolved fluorescence. The results showed the compound had high quantum yield. The cross-section of two-photon absorption (TPA) of the compound was measured by using femtosecond laser in dichloromethane solution. The result indicated the cross-section maximum of two-photon absorption was 430 GM at 600 nm. These results made the compound of great interest as a new fluorescent probe and photoluminescence material.     

An Optically and Thermally Switchable Electronic Structure Based on an Anthracene–BODIPY Conjugate

An optically and thermally responsive boron dipyrromethene (BODIPY) dye, namely, meso‐2‐(9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dione) (DK)‐linked, bicyclo[2.2.2]octadiene (BCOD)‐fused BODIPY ( BCOD‐DK ), was synthesized. The weakly luminous structure of BCOD‐DK can be changed quantitatively to that of the strongly fluorescent BODIPY BCOD‐Ant by optical excitation at the DK unit, which induces double decarbonylation of the DK unit to give an anthracene unit. The solvent effect on the fluorescence properties of BCOD‐DK suggests that the dramatic change in fluorescence intensity is controlled by intramolecular electron transfer from the BODIPY moiety to the meso‐DK substituent. BCOD‐DK is converted to meso‐ DK benzene‐fused BODIPY ( Benzo‐DK ) by heating at 220 °C with 64–70 nm redshift of absorption and fluorescence peaks without changing the fluorescence quantum yield of Φ_F=0.08 in dichloromethane. Benzo‐DK can be converted to strongly fluorescent meso ‐ anthracene benzene‐fused BODIPY Benzo‐Ant by optical excitation. Thus, BCOD‐DK can show four different optical performances simply by irradiation and heating, and hence may be applicable for optical data storage and security data encryption.     

Highly luminescent network films from electrochemical deposition of peripheral carbazole functionalized fluorene oligomer and their applications for light-emitting diodes

Highly luminescent network films on flat indium tin oxide (ITO) substrates are prepared by electropolymerization using an electroactive and fluorescent compound as precursor; the LEDs prepared using these films as a light emitting layer achieve the maximum luminance and external quantum efficiency of 4224 cd/m(2) and 0.72%, respectively, which demonstrates that electrochemical synthesis can be a new route to construct the highly luminescent films.     

9,10⁃二(N⁃苯基吲哚⁃3⁃乙烯基)蒽的合成及聚集诱导荧光和压致荧光变色性质

通过简单的Wittig反应合成了一个荧光化合物9,10-二(N-苯基吲哚-3-乙烯基)蒽(IA-Ph); 通过核磁共振和质谱对其结构进行了确认; 利用荧光发射光谱和紫外吸收光谱对其光物理性质进行了表征. 结果表明, 化合物IA-Ph兼具聚集诱导荧光(AIE)和压致荧光变色性质, 在相同浓度下, 该化合物在THF/H₂O(体积比1∶9)混合溶液中的荧光强度比在纯四氢呋喃(THF)溶液中增加了12倍, 具有明显的AIE效应. 通过简单而有效的机械力研磨, 化合物可以从初始的发绿光转变为研磨后的橙红光, 光谱红移约68 nm; 而且在加热或溶剂熏蒸条件下, 化合物的颜色可以回复到起始的绿光, 具有完全可逆性.