双光子诱导有机光致变色材料的研究进展

在介绍舣光子诱导有机光致变色材料性能的基础上,重点介绍双光子诱导光致变色材料种类、光致变色原理及在三维信息存储、生物技术研究和荧光共振能量转移方面的应用.最后对双光子诱导有机光致变色材料的研究趋势做了展望.     

2,5-二氰基-1,4-二（3′,4′,5′-三甲氧基苯乙烯基）苯的合成和非线性光学性质

报道了具有典型D-A-D型共轭结构的反式2,5-二氰基-1,4-二(3′,4′,5′-三甲氧基苯乙烯基)苯(TMOS)的合成和非线性光学性质。用核磁、红外和元素分析进行了表征。测试了紫外吸收光谱、单光子荧光光谱、双光子荧光光谱及双光子吸收截面。在800 nm的飞秒脉冲激光激发下,目标化合物发出很强的黄绿色上转换荧光。TMOS的最大吸收波长、单光子荧光波长、双光子荧光波长、荧光量子产率、双光子吸收系数、最大双光子吸收截面及双光子荧光寿命分别是395 nm、523 nm5、26 nm、0.26、1.2 cm.GW-14、05 GM、230 ps。这些数据表明对位甲氧基的D-A-D型化合物具有较好的双光子吸收性能,TMOS是细胞中DNA双光子荧光显微与成像应用的良好候选材料。     

2,5-二氰基-1,4-二(3'',4'',5''-三甲氧基苯乙烯基)苯的合成和非线性光学性质

报道了具有典型D-A-D型共轭结构的反式2,5-二氰基-1,4-二(3′,4′,5′-三甲氧基苯乙烯基)苯(TMOS)的合成和非线性光学性质.用核磁、红外和元素分析进行了表征.测试了紫外吸收光谱、单光子荧光光谱、双光子荧光光谱及双光子吸收截面.在800 nm的飞秒脉冲激光激发下,目标化合物发出很强的黄绿色上转换荧光.TMOS的最大吸收波长、单光子荧光波长、双光子荧光波长、荧光量子产率、双光子吸收系数、最大双光子吸收截面及双光子荧光寿命分别是395 nm、523 nm、526 nm、0.26、1.2 cm·GW-1、405 GM、230 ps.这些数据表明对位甲氧基的D-A-D型化合物具有较好的双光子吸收性能,TMOS是细胞中DNA双光子荧光显微与成像应用的良好候选材料.     

2,5-二氰基-1,4-二(4′-甲氧基苯乙烯基)苯的合成和非线性光学性质

报道了具有典型D-A-D型共轭结构的反式2,5-二氰基-1,4-二(4′-甲氧基苯乙烯基)苯(DCHO)的合成。用核磁、红外和元素分析进行了表征。测试了紫外吸收光谱、单光子荧光光谱、双光子荧光光谱及双光子吸收截面。在800 nm的飞秒脉冲激光激发下,标题化合物发出很强的绿色上转换荧光。化合物2,5-二氰基-1,4-二(4′-甲氧基苯乙烯基)苯的最大吸收波长、单光子发射波长、最大双光子荧光波长、荧光量子产率、双光子吸收系数及双光子吸收截面分别是393 nm、470 nm、475 nm、0.12、0.8 cm/GW、270 GM。这些数据表明,对位甲氧基的D-A-D型化合物具有较好的双光子吸收性能,DCHO是双光子荧光显微与成像应用的一个良好的候选材料。     

比率型过氧化氢荧光探针的合成及成像应用

采用6-甲氧基苯并噻唑-2-羟基喹啉作为双光子荧光团、硼酸酯作为过氧化氢（H2O2）识别基团，合成比率型检测H2O2的双光子荧光探针{6-甲氧基-2-[6-(4,4,5,5-四甲基-1,3,2-二氧硼杂环戊烷-2-基)喹啉-2-基]苯并[d]噻唑}（MQH2O2）。利用荧光光谱和双光子荧光光谱对探针进行H2O2响应能力的评估，结果显示探针具有良好的H2O2比率响应（30 min内比率信号增强约25.4倍、检出限低至38.6 nmol/L）和双光子性质（最大双光子荧光活性截面为150 GM）。通过双光子共聚焦成像完成了细胞和大脑组织成像，结果表明该探针能够实现脑卒中诱导细胞氧化应激的原位成像分析。     

2,5-二氰基-1,4-二(4′-甲氧基苯乙烯基)苯的合成和非线性光学性质

报道了具有典型D-A-D型共轭结构的反式2,5-二氰基-1,4-二(4′-甲氧基苯乙烯基)苯(DCHO)的合成.用核磁、红外和元素分析进行了表征.测试了紫外吸收光谱、单光子荧光光谱、双光子荧光光谱及双光子吸收截面.在800 nm的飞秒脉冲激光激发下,标题化合物发出很强的绿色上转换荧光.化合物2,5-二氰基-1,4-二(4′-甲氧基苯乙烯基)苯的最大吸收波长、单光子发射波长、最大双光子荧光波长、荧光量子产率、双光子吸收系数及双光子吸收截面分别是393 nm、470 nm、475 nm、0.12、0.8 cm/GW、270 GM.这些数据表明,对位甲氧基的D-A-D型化合物具有较好的双光子吸收性能,DCHO是双光子荧光显微与成像应用的一个良好的候选材料.     

两个D-π-A型双氰基二苯乙烯双光子荧光染料的合成

该文合成了两个以双氰基二苯乙烯为母体的D-π-A型双光子荧光染料,并以其作为模型化合物对双氰基与末端取代基对双光子吸收的影响进行了系统研究。两个化合物(DMO和DMA)具有大的双光子吸收截面(δ)。含有末端氨基的DMA较末端甲氧基的DMO具有更长的发射波长〔λem(DMA)=554 nm>λem(DMO)=459 nm〕、更大的双光子吸收截面〔δ(DMA)=3 650 GM>δ(DMO)=830 GM〕和更高的荧光量子产率〔η(DMA)=0.456>η(DMO)=0.294〕。理想的末端取代基不是烷氧基而是取代氨基。这类双氰基二苯乙烯染料拥有小的分子尺寸、大的δ(830～3 650 GM)、长的发射波长(459～554 nm)和大的斯托克斯位移(St)(131～150 nm),是比较理想的用于双光子荧光标记和探针的发色团。     

双光子镉离子荧光探针TPCN合成及光谱性质研究

双光子荧光探针具有长波激发、短波发射的特点,可以有效避免样品本底荧光和散射光的干扰,在生物分析中有较多应用。通过Wittig-Horner反应合成了发光机理为分子内电荷转移(ICT)型、分子构型为D-A-D型(A表示电子受体,D表示电子给体)的双光子镉离子荧光探针TPCN。探针随镉离子浓度增加,荧光强度呈线性下降并伴随红移现象发生,检测线性范围为3.00×10~(-6)～1.00×10~(-4) mol/L,检测限可达4.00×10~(-7) mol/L。并由于探针荧光团中心存在吸电子能力较强的氰基,增加了分子内的电荷迁移能力,使探针有较大的双光子吸收截面。     

一个衍生于苯并15-冠-5的双光子荧光钠离子探针

钠离子在人体生理与病理上起着关键性的作用，特别是在神经传导、肌肉与心脏收缩、电解质平衡、阳离子运输和细胞容积等方面都发挥着至关重要的功能。因此，开发用于细胞中钠离子三维动态成像的双光子荧光探针显得尤为重要。以苯并15-冠-5和双氰基二苯代乙烯分别作为钠离子受体与双光子荧光团开发出探针DNa，对DNa的结构进行了表征鉴定。探针DNa具有诸如小的分子尺寸、大的双光子吸收截面（δTPA, 1054 GM）、极好的光稳定性、适宜的水溶性和优良的细胞渗透性等优点. DNa对Na 显示了优良的专一选择性，不受其它离子的干扰，对Na 的解离常数Kd ＝ 23 ? 2 mmol?L-1。DNa能用于细胞中Na 的三维成像，是一个性能优良的双光子荧光探针。     

苯并15-冠-5为受体的双光子荧光钠离子探针

以苯并15-冠-5和双氰基二苯代乙烯分别作为钠离子受体与双光子荧光团开发出探针(DNa)。采用核磁共振谱和质谱对DNa的结构进行了确证,同时对其光物理性能进行了表征。探针DNa具有小的分子尺寸、大的双光子吸收截面(δTPA,1054GM)、极好的光稳定性、适宜的水溶性和优良的细胞渗透性。DNa对Na~+显示优良的专一选择性,不受其他离子的干扰,对Na~+的解离常数Kd=(23±2)mmol/L。DNa能用于细胞中Na~+的三维成像,是性能优良的双光子荧光探针。     

Recent Advances in Two-Photon AIEgens and Their Application in Biological Systems

Two-photon fluorescence imaging technology has the advantages of high light stability, little light damage, and high spatiotemporal resolution, which make it a powerful biological analysis method. However, due to the high concentration or aggregation state of traditional organic light-emitting molecules, the fluorescence intensity is easily reduced or disappears completely, and is not conducive to optimal application. The concept of aggregation-induced emission (AIE) provides a solution to the problem of aggregation-induced luminescence quenching (ACQ), and realizes the high fluorescence quantum yield of luminescent molecules in the aggregation state. In addition, two-photon absorption properties can readily be improved just by increasing the loading content of AIE fluorogen (AIEgen). Therefore, the design and preparation of two-photon fluorescence probes based on AIEgen to achieve high-efficiency fluorescence imaging in vitro/in vivo has become a major research hotspot. This review aims to summarize representative two-photon AIEgens based on triphenylamine, tetraphenylethene, quinoline, naphthalene and other new structures from the past five years, and discuss their great potential in bioimaging applications.     

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)]     

Two-photon absorption dyes with thiophene as π electron bridge: Synthesis, photophysical properties and optical data storage

Four novel dyes are prepared by thiophene as π bridge between carbazole central core and other terminal groups by Suzuki and Heck coupling reactions. These dyes are fully characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. Linear absorption, single- and two-photon excited fluorescence in various solvents are experimentally investigated. The calculated two-photon absorption cross sections of 9-Hexyl-3,6-di((5-phenyl)-2-thienyl)carbazole (1), 9-Hexyl-3,6-di((5-thienyl)-2-thienyl)carbazole (2), 9-Hexyl-3,6-di((5-p-vinylpyridyl)-2-thienyl)-carbazole (3) and 9-Hexyl-3,6-di-((5-o-vinylpyridyl)-2-thienyl)carbazole (4) for the lowest excited state are 537.84, 550.76, 1292.95 and 1340.40 × 10⁻⁵⁰ cm⁴ s photon⁻¹, respectively. Calculated and experimental data have shown that thiophene as π electron bridge improves the two-photon absorption cross sections greatly. Two-photon optical data recording experiments have been carried out at 820 nm laser radiation.     

高聚物双光子吸收材料研究进展

高聚物双光子吸收材料具有强度高与韧性好的特征，可以在膜状态下使用，因而具有潜在应用前景。介绍了双光子材料的应用，综述了高聚物双光子吸收材料的研究进展情况。     

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.     

Bright two-photon emission and ultra-fast relaxation dynamics in a DNA-templated nanocluster investigated by ultra-fast spectroscopy

Metal nanoclusters have interesting steady state fluorescence emission, two-photon excited emission and ultrafast dynamics. A new subclass of fluorescent silver nanoclusters (Ag NCs) are NanoCluster Beacons. NanoCluster Beacons consist of a weakly emissive Ag NC templated on a single stranded DNA ("Ag NC on ssDNA") that becomes highly fluorescent when a DNA enhancer sequence is brought in proximity to the Ag NC by DNA base pairing ("Ag NC on dsDNA"). Steady state fluorescence was observed at 540 nm for both Ag NC on ssDNA and dsDNA; emission at 650 nm is observed for Ag NC on dsDNA. The emission at 550 nm is eight times weaker than that at 650 nm. Fluorescence up-conversion was used to study the dynamics of the emission. Bi-exponential fluorescence decay was recorded at 550 nm with lifetimes of 1 ps and 17 ps. The emission at 650 nm was not observed at the time scale investigated but has been reported to have a lifetime of 3.48 ns. Two-photon excited fluorescence was detected for Ag NC on dsDNA at 630 nm when excited at 800 nm. The two-photon absorption cross-section was calculated to be ～3000 GM. Femtosecond transient absorption experiments were performed to investigate the excited state dynamics of DNA-Ag NC. An excited state unique to Ag NC on dsDNA was identified at ～580 nm as an excited state bleach that related directly to the emission at 650 nm based on the excitation spectrum. Based on the optical results, a simple four level system is used to describe the emission mechanism for Ag NC on dsDNA.     

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 ?-conjugated bridging unit can enhance the two-photon absorption and two-photon fluorescence.     

细胞内铜离子的双光子荧光成像

基于无荧光的螺环结构与具有荧光的开环酰胺的平衡反应，本文合成了一个能在水基的缓冲溶液中选择性地识别Cu^2＋的罗丹明衍生物FD2．当在HEPES缓冲溶液中加入10当量的Cu^2＋时，FD2的单光子激发荧光和双光子激发荧光的强度均表现出明显的增强；更为重要的是，运用双光子荧光显微技术可以选择性地对活细胞内Cu^2＋进行成像．     

三(4-碘苯基)胺的合成工艺研究

以氮气为保护气,采用三苯胺作为起始原料,合成了三苯胺类双光子吸收材料的重要中间体三(4-碘苯基)胺,并通过高效液相分析仪和核磁共振谱分别对产品的纯度和结构进行分析。通过对单因素的研究,实验结果显示:氮气保护下,反应的优化投料比n(三苯胺)∶n(碘化钾)∶n(碘酸钾)=1∶2.25∶2.25。三(4-碘苯基)胺的反应收率可达80.4%,纯度大于99.8%。