The synthesis and two-photon excited fluorescence properties of novel branched fluorene derivatives

Two novel, V-shaped fluorene derivatives branched from triphenylamine and their linear analogue were synthesized via Cu-mediated Ullmann condensation and subsequent Pd-catalyzed Heck coupling reaction. Their two-photon excited fluorescence properties as well as their linear absorption and single-photon excited fluorescence properties were examined. When excited at 730 nm by a Ti:sapphire femtosecond laser, the compounds exhibited strong two-photon excited blue fluorescence. The two-photon excited fluorescence cross-sections of V-shaped derivatives in toluene at 730 nm were ∼506 GM in the case of N, N-bis{7-[4′-(N, N-diphenylamino)styryl]-9,9-diethyl-9H-fluorene-2-yl}-aniline) and 397 GM for N, N-Bis{7-[4′-(N, N-diphenylamino)styryl]-9,9-diethyl-9H-fluorene-2-yl}-4-acetyl-aniline), respectively.     

Synthesis and characterization of 2,5-bis[4-(2-arylvinyl) phenyl]-1,3,4-oxadiazoles with two-photon fluorescence properties

Four novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on “push-core-pull-core-push” molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig-Horner reaction. Their chemical structures were determined to show trans-vinylene character according to infrared (IR) and ¹H nuclear magnetic resonance (NMR) spectra. A very effective energy transfer from the excited units to the π-conjugated bridging unit can enhance the two-photon absorption and two-photon fluorescence. __________ Translated from Journal of Southeast University (Natural Science Edition), 2006, 36(5): 795–798 [译自: 东南大学学报 (自然科学版)]     

Computational study of the one- and two-photon absorption properties of macrocyclic thiophene derivatives

The geometrical structure, electronic structure, one-photon and two-photon absorption properties of a series of macrocyclic thiophene derivatives C[3T_DA]_n (n = 2-5) have been studied using density functional theory (DFT) and Zerner’s intermediate neglect of differential overlap (ZINDO) methods theoretically. The results showed that the range of λ⁽¹⁾_maxs is 390-470 nm and λ⁽²⁾_maxs is 640-670 nm, while, both λ⁽¹⁾_max and λ⁽²⁾_max gradually enlarge as increasing the number of the C[3T_DA] unit. And C[3T_DA]_n compounds exhibited large TPA cross-section (δ_max), and the factors influencing on the δ_max values were analyzed in detail. Transition dipole moments M_0k and M_kn play important roles on δ_max. Both π-electron number (N_e) and the product of oscillator strengths from ground state to mediate state (?_0k) and from mediate state to final state (?_kn) are in proportion to δ_max. Moreover, δ_max linearly depends on the static second-order nonlinear optical susceptibilities (β₀).     

Synthesis, optical properties and ultrafast dynamics of a 2,1,3-benzothiadiazole-based red emitter with intense fluorescence and large two-photon absorption cross-section

A new 2,1,3-benzothiadiazole-based red fluorescent compound with a D-A-D type structure was synthesized and characterized. The central 2,1,3-benzothiadiazole core was symmetrically connected via the 4,7-positions with two donor groups in which the 7-position of a fluorenyl ring was substituted with a carbazol-9-yl moiety and the 2-position was substituted by a 5-thienyl moiety. The carbazol moieties were further derivatized by two 2-naphthyl moieties at the 3,6-positions. Femtosecond laser spectroscopic techniques including excited state fluorescence and pump-probe technique investigations, together with steady state absorption and one-photon fluorescence spectra, were employed to systematically investigate the optical properties and ultrafast dynamics of the new compound in tetrahydrofuran solution. It shows a large two-photon absorption cross-section and high fluorescence quantum yield, indicating potential application in two-photon fluorescence imaging field. The ultrafast dynamics results reveal competition between a pure excited state relaxation process and stimulated radiation in the red wavelength region.     

Synthesis, characterization and third-order non-linear optical properties of novel fluorene monomers and their cross-conjugated polymers

We designed and synthesized two novel fluorene monomers of D-A-D (donor-acceptor-donor) type (M1 and M2), and their two corresponding polymers (PM1 and PM2) and a copolymer (CPM). These high molecular weight, film-forming polymers were obtained from metal-free, superacid-catalyzed reactions of the monomers with N-phenylisatin. The cubic NLO response (χ⁽³⁾) for these new compounds, in solid thin films, was measured through the use of third-harmonic generation (THG) Maker-Fringes technique at IR wavelengths given values of the order of 10⁻¹² esu from which, the corresponding second hyperpolarizabilities (γ) were estimated to be of the order of 10⁻³³ esu for monomers and 10⁻³¹ esu for polymers. Second hyperpolarizabilities have also been estimated theoretically at B3LYP/6-31G(d) level of theory in gas phase and related with the electronic structure of the synthesized molecules.     

Synthesis and photovoltaic properties of an alternating polymer based fluorene and fluorine substituted quinoxaline derivatives

An alternating polymer (PFOFTQx) with 9,9-dioctylfluorene (FO) as electron-rich unit and fluorine substituted quinoxaline (FTQx) as electron-withdrawing unit was synthesized and characterized. PFOFTQx showed similar absorption property with that of the counterpart polymer without fluorine atom (synthesized APFO-15). However, the low-lying highest occupied molecular orbit (HOMO) energy level of PFOFTQx was ?5.37 eV, about 0.07 eV smaller than that of synthesized APFO-15. In order to study the photovoltaic properties of the materials, polymer solar cells (PSCs) were fabricated with PFOFTQx as donor blended with [6,6]-phenyl-C61-butyric acid methyl ester (PC₆₁BM) as acceptor. The power conversion efficiency (PCE) of PSC was 1.77% with a high open-circuit voltage (V_oc) of 0.90 V for an optimized PFOFTQx:PC₆₁BM weight ratio of 1:5, in comparison with that of synthesized APFO-15-based device (PCE of 1.60% with V_oc of 0.77 V). This study indicated that fluorine substituted quinoxaline-based polymers would be promising material with a higher V_oc for the application in polymer solar cells.     

两个新的2-萘酮衍生物的合成与光物理性质

以咔唑为电子给体、羰基为电子受体,合成了一个新的D-π-A型有机染料1(1-(2-萘基)-3-(N-乙基咔唑)-丙烯酮)和一个新的以咔唑为电子给体中心的A-π-D-π-AV型双枝有机染料2(3,6-二[1-(2-萘基)丙烯酮]-N-丁基咔唑)。系统研究了它们在不同溶剂和聚合物基质中的光物理性质。研究发现,双枝有机染料2相对于单枝染料1吸收和荧光强度大大增强,在聚合物基质中的荧光强度相对于溶液中大大增强,即使掺杂浓度较高时也没有因生成分子的聚集体而发生明显的荧光猝灭。     

The synthesis and characterization of photonic materials composed of substituted fluorene donors and a porphyrin acceptor

Three novel porphyrin derivatives namely 5,10,15,20-tetra-[7-cyanophenyl-9,9’-bis-(2-ethylhexyl)fluoren-2-yl]-porphyrin, 5,10,15,20-tetra-[7-(4-acetylphenyl)-9,9’-bis-(2-ethylhexyl)fluoren-2-yl]-porphyrin and 5,10,15,20-tetra-[7-pyrenyl-9,9’-bis-(2-ethylhexyl)fluoren-2-yl]-porphyrin were synthesized. Substitution of the aryl groups on the meso-fluorene using Suzuki-Miyaura coupling enabled a study to be undertaken of the energy transfer from the meso fluorenyl to the porphyrin core. To calculate the extent of energy transfer, the corresponding model fluorene compounds 7-cyanophenyl-9,9’-bis-(2-ethylhexyl)fluorene, 7-acetylphenyl-9,9’-bis-(2-ethylhexyl)fluorene and 7-pyrenyl-9,9’-bis-(2-ethylhexyl)fluorene were also synthesized. Fluorescence studies of both the porphyrin derivatives and model compounds showed efficient energy transfer occured from the aryl-fluorene donor to the porphyrin acceptor. Upon excitation, due to energy transfer, a characteristic porphyrin emission was observed at 656 nm; 99% energy transfer in solution was observed in these donor–acceptor systems. Thin-film emission results indicate a low degree of aggregation in the donor–acceptor systems.     

Synthesis and properties of new novolacs based on heteroatom‐bridged phenol derivatives

We describe the synthesis and properties of new novolacs prepared by addition‐condensation of heteroatom‐bridged phenol derivatives and formaldehyde. The trifluoroacetic acid‐catalyzed polymerization of equimolar amounts of bis(4‐methoxyphenyl) ether ( 1a ) and formaldehyde proceeded homogeneously to afford the polymer ( 2a ) in 49% yield (M_n 2600, M_w/M_n 1.8). From the FTIR, ¹H‐NMR, and ¹³C‐NMR spectra of 2a , it was evident that the polymer had methylene moieties‐bridged repeating units in the polymer backbone. A higher molecular weight novolac ( 2a ′) (yield 99%, M_n 16,600, M_w/M_n 12.9) could be prepared by using an excess of formaldehyde. Bis(4‐methoxyphenyl) sulfone novolac ( 2b ) (M_n 1300, M_w/M_n 1.2) and bis(4‐methoxyphenyl) sulfide novolac ( 2d ) (M_n 1200, M_w/M_n 1.9) were also prepared. However, the polymerization of bis(4‐hydroxyphenyl) sulfone ( 1c ) did not proceed, even when it was attempted under various reaction conditions. From TGA, the temperatures at 10% loss in weight (T₁₀) for 2a , 2a ′, and 2b were found to be 413, 430 and 393°C, respectively. These results suggested that heteroatom‐bridged novolacs based on phenol derivatives have good thermal stability than other organosoluble polymers; moreover, these novolacs could be expected to function as processable materials, polymer blends for engineering plastics, etc. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The synthesis,two-photon absorption and blue upconversion fluorescence of novel,nitrogen-containing heterocyclic chromophores

Novel, nitrogen-containing heterocyclic chromophores based on either 1,2,4-triazine or an imidazole core were synthesized using a three-component, one-pot reaction under microwave irradiation. Structures were verified by ¹H NMR, IR, MS and elemental analyses while crystal structure was determined using X-ray diffraction. The two-photon absorption and two-photon upconverted blue fluorescent emission characteristics were investigated experimentally; preliminary structure–photophysical property relationships were established. Chromophores that contained the imidazole moiety displayed more potent two-photon absorption than compounds based upon 1,2,4-triazine and also exhibited a strong two-photon upconverted blue fluorescent emission peak at around 443–476 nm. Significant enhancement of the two-photon absorption cross-section was achieved by fusing a benzoxazole moiety onto the phenanthro[9,10-d]imidazole ring.     

新型含芴Schiff碱化合物的合成及其紫外-可见光谱性能研究

通过9-芴甲醛与相应的芳胺衍生物反应合成了两种新型含芴Schiff碱化合物:9-亚甲基19-亚(2-氨基芴)基芴和9-亚甲基-9-亚(2-甲基苯胺)基芴,其结构经核磁共振谱、红外光谱和质谱表征.吸收光谱法测定了两种含芴Schiff碱衍生物在乙醇、四氢呋喃、环己烷和氯仿中的最大吸收波长(λmax),并探讨了分子结构和溶剂...     

A water-soluble D–π–A chromophore based on dipicolinic acid: Synthesis, pH-dependent spectral properties and two-photon fluorescence cell imaging

The presence of two carboxylic acid groups and two hydroxyl groups within the novel dye, (E)-4-(4-bis(2-hydroxyethyl)amino)styryl)pyridine-2,6-dicarboxylic acid, resulted in good water solubility. The compound's UV absorption and photoluminescence spectra were each highly pH sensitive in acidic solutions and two isobestic points were observed. The TPA cross-section coefficient and two-photon fluorescence cell imaging of the dye were investigated.     

邻菲啉衍生物的合成及光谱性质的研究

合成了4,5-二氮杂芴-9-酮缩氨基硫脲和4,5-二氮杂芴-9-酮缩氨基脲两种邻菲啉的衍生物.用1HNMR、IR、MS表征了其结构,通过紫外可见光谱和荧光光谱研究了其光谱性质,发现两种新化合物具有良好的荧光特性.     

2-芳基苯并呋喃化合物的新法合成与表征

创造了两步合成2-芳基苯并呋喃化合物的新方法。即利用水杨醛或取代水杨醛在低价钛作用下进行交叉McMurry偶联反应,并对交叉偶联产物-邻乙烯基苯酚进行氧化环化获得对应苯并呋喃化合物。此法为脱甲氧基野茉莉醇、野茉莉醇等天然产物的全合成提供了简便有效的方法。     

双取代聚乙炔衍生物的合成与光学性能研究

用WCl6-Ph4Sn催化下聚合生成了双取代乙炔衍生物,在产物的红外光谱上,2 205 cm-1处C-C键的伸缩振动特征吸收峰消失及1 621 cm-1处C=C双键的生成,这些特征变化证明了聚合反应的发生。单体苯丙炔酸通过肉桂酸的加成消去反应制得,单体C6H5C-CCOO(C6H4)OCOCH2CH3则通过苯丙炔酸和对羟基苯甲酸乙酯酯化制得,通过红外光谱、元素分析、XRD、紫外光谱和荧光光谱对聚合物结构和性质进行了表征,结果显示,这种共轭聚合物在光激发下能发出蓝光且聚合物能溶于普通的有机溶剂。     

环糊精及其衍生物功能性能研究进展

综述了环糊精及其衍生物功能性能研究方面的进展。主要包括增溶性能、稳定效应、选择识别性能、生物酶性能、光化学性能以及电化学性能等。     

The synthesis of tetrahedral bipyridyl metallo-octupoles with large second- and third-order nonlinear optical properties

Two new 4,4′-bis(donor)-6,6′-diphenyl- 2,2′-bipyridine ligands and their corresponding D_2d (Cu^I, Ag^I, Zn^II) octupolar metal complexes were synthesized, and their linear and nonlinear optical properties were investigated. A single crystal X-ray structure was also determined for the bis[4,4′-bis(diethylaminostyryl)-6,6′-diphenyl-bipyridine]copper(I) complex, which revealed a distorded pseudo-tetrahedral geometry. Molecular second-order nonlinear optical properties were determined for the complexes using the Harmonic Light Scatterring technique at 1.91 μm. These metallo-chromophores display large first hyperpolarizabilities β_1.91 in the range of 211-340 × 10⁻³⁰ esu, which increase with the Lewis acidity of the metal ion. The two-photon absorption properties of the bipyridyl ligands and related complexes were determined using either the two-photon emission method for fluorescent compounds or the open aperture Z-scan technique for non emissive ones. The complexes display red-shifted two-photon absorption bands compared to their metal-ion free chromophores, as well as a large increase of the maximum two-photon absorption cross-sections.     

Synthesis and photoluminescent properties of polymer containing perylene and fluorene units

A new luminescent polymer, F-PTCD, with N,N′-bis-(propenylaniline)-3,4,9,10-perylene tetracarboxylic diimide-emitting segments (PTCD) and 9,9-diphenylfluorene (DIPT) was synthesized by Heck reaction. The structures were characterized by MS, EA, ¹H NMR, IR and the photoluminescent (PL) properties were investigated by UV/vis absorption and fluorescence emission spectra. The fluorescence quantum yield was 0.453 in acetone. Thermogravimetric analysis and differential scanning calorimetry showed that the polymer is thermal stable up to 569 °C with glass-transition temperature higher than 125 °C. They are yellow-red emitting materials with the band gap of 2.33 eV estimated from the onset absorption. In addition, the emission can be quenched by both electron donor (N,N-dimethylaniline) and electron acceptor (Fullerene), where the processes followed the Stern-Volmer equation. Furthermore, the interaction between F-PTCD and carbon nanotubes (CNTs) was also studied by fluorescent quenching.     

聚苯砜对苯二甲酰胺/苝系荧光材料复合静电纺膜的制备与表征

聚苯砜对苯二甲酰胺(PSA)纤维在防护领域具有广泛的应用,笔者在其纺丝溶液中引入苝系荧光功能材料POSS-PDI-POSS,通过静电纺制备了PSA纤维膜。研究了助纺剂聚丙烯腈(PAN)、共溶剂氯仿、荧光功能材料的引入对PSA溶液流变、电导率和纺丝成形性能的影响,发现在PAN添加量为3%(w)、氯仿添加量为6%(w)和0.4%(w)的POSS-PDI-POSS时可制备纤维直径集中分布在250～600 nm的纤维膜,该纤维膜可发射550 nm的黄绿色荧光(490 nm光激发)和发射580 nm的红色荧光(530 nm光激发)。     

Pechmann反应合成4-甲基香豆素及光谱性能的研究

以取代苯酚和乙酰乙酸乙酯为原料,对甲基苯磺酸为催化剂,采用Pechmann反应合成了5个4-甲基香豆素衍生物,采用核磁共振、红外光谱对合成的化合物进行了结构表征,并测定了它们的的紫外吸收光谱和荧光发射光谱等性能。