氧芴三苯胺多枝分子的双光子吸收与电化学行为

研究了3个氧芴/三苯胺衍生物: E-2,8-双(4-二苯胺基苯乙烯基)氧芴(简称OT-G1)、E-2,8-双[4-(二苯基氨基-二苯乙烯基)(4’-溴苯基)氨基-苯乙烯基]氧芴(简称OT-G1.5)和E-2,8-双-[4’,4″-二-(二苯胺基苯乙烯基)-4-二苯胺基苯乙烯基]氧芴(简称OT-G2)的双光子吸收和电化学行为. 研究结果表明, 分子“代数”从1→1.5→2增高, 氧芴三苯胺多枝分子的HOMO能级升高、双光子荧光强度和双光子吸收截面明显增大. 由于HOMO能级的升高有利于分子的电荷转移, 因而分子表现出强的双光子吸收能力, 这表明可通过电化学行为来推断出分子的双光子吸收性能.     

具有大的双光子吸收截面的A-A-A型双苯乙烯基苯类化合物的合成

合成了A-A-A型双苯乙烯基苯类化合物FR[2,5-二氰基-1,4-二(4'-氟苯乙烯基)苯],并采用核磁共振、红外光谱和元素分析等手段对其进行了表征.用飞秒脉冲诱导荧光光谱法分别研究了2个A-A-A型双苯乙烯基苯类化合物FR与CY[2,5-二氰基-1,4-二(4'-氰基苯乙烯基)苯]以及2个D-A-D型双苯乙烯基苯类化合物MO[2,5-二氰基-1,4-二(4'-甲氧基苯乙烯基)苯]和MA[2,5-二氰基-1,4-二(4'-二甲胺基苯乙烯基)苯]的单、双光子吸收与发射特性.实验结果表明,最大单光子吸收与发射波长随末端取代基供电子能力的增强而增大,末端强吸电子基化合物FR和CY具有相当高的荧光量子产率(分别为0.92与0.89)、较长的荧光寿命(分别为5.8与6.1 ns)及较大的双光子吸收系数(分别为19.1与20.5).末端带强吸电子基的化合物FR与CY的双光子吸收截面(δ,分别为6350 GM和6870 GM)比末端带供电子基的化合物MO和MA的δ(分别为270 GM与1790 GM)要大得多,表明A-A-A型双苯乙烯基苯类化合物具有异常大的δ.     

二噻吩衍生物的合成及其线性、非线性光谱性质

合成了一系列二噻吩衍生物类有机合物：5，5'-二（对－N，N－二甲胺基苯乙 烯基）－2，2'－二噻吩（BMSBT）与5，5'－二（对－N，N－二乙胺基苯乙烯基）- 2,2'-二噻吩（BESBT），5,5'-二（对N－环丁胺基苯乙烯基）－2,2'－二噻吩（ BBSBT），5,5－二（对－N－咔唑基苯乙烯基）2-2'－二噻吩（BCSBT），并测定了 其吸收光谱、单光子荧光光谱和双光子荧光光谱。BMSBT，BESBT和BBSBT的单光子 荧光参数存在的很强的、规则的溶剂效应，表明其激发态的分子可能有较大的极性 。在800nm fs激光下测得BMSBT与BESBT在560nm附近（与单光子荧光发射峰波长接 近的位置）有较强的上转换荧光发射，上转换荧光强度与激发能量之间较好的平方 关系表明了双光子激发的机理，这种上转换荧光被称为双光子荧光。用以光子荧光 法测得BMSBT和BESBT的双光子吸收截面分别为54*10~(-50)(cm~4·s)/photon和 102*10~(-50)(cm~4·s)/photon。     

高选择性氟离子识别受体的设计与识别机理

将酰胺识别基团耦合至基态具有分子内电荷转移特征的对硝基苯基偶氮苯胺分子中,设计合成了受体分子N-苯甲酰基4-(4'-硝基苯基偶氮基)苯胺(3),对氟离子表现出极高的识别选择性.乙腈中该受体3的最大吸收峰位于380 nm,加入氟离子后,该吸收峰强度逐渐减弱,同时在530 nm处出现新的吸收峰,后者为受体分子与氟离子形成的1:1配合物的吸收峰.溶剂极性效应实验表明,该吸收峰具有电荷转移特征.引入氟离子后受体3溶液的颜色由浅黄色转变为紫红色,可实现氟离子的裸眼检测.质子溶剂效应,1H NMR滴定为受体分子3与阴离子间的氢键作用本质提供了直接证据.     

以二苯甲酮为端基的第一代树状取代酞菁锌的合成

4-甲基二苯甲酮经N-溴代丁二酰亚胺溴代制得4-溴甲基二苯甲酮(1);1与3,5-二羟基苯甲醇反应合成了外围带有二苯甲酮取代基的第一代树枝状分子3,5-二(二苯甲酮-4-甲氧基)苯甲醇(2);2与4-硝基邻苯二甲腈缩合制得外围带有二苯甲酮取代基的第一代树枝状分子4-[3,5-二(二苯甲酮-4-甲氧基)苯甲氧基]邻苯二甲腈(3);3经"液相法"环合生成外围带有二苯甲酮取代基的第一代树枝状分子取代的酞菁锌配合物——四[3,5-二(二苯甲酮-4-甲氧基)苯甲氧基]锌酞菁[ZnPc(C35H27O5)4],其结构经UV,1HNMR,IR和MS表征。     

负载芳基苄醚树枝形酞菁锌聚合物纳米粒子的合成及其离体光动力活性

首先将对氰基溴化苄与3,5-二羟基苯甲醇通过Frétchet反应合成芳基苄醚树枝分子3,5[二-(4'-氰基苯甲氧基)]苯甲醇(1),1与4-硝基邻苯二甲腈合成前驱物4-{3',5'-[二-(4"-氰基苯甲氧基)]}苯甲氧基邻苯二甲腈(3),然后3在乙酸锌,1,8-二氮杂二环(5,4,0)-7-十一烯(DBU)和正戊醇...     

对位取代二苯乙烯衍生物的合成和非线性光学性质

合成了反式-4-[N-（乙氧基羰基-4"-硝基苯基）-N'-乙基氨基]-4'-(二甲基氨 基)二苯乙烯(DMANHAS)和三个新有机化合物。用核磁、红外以及元素分析进行了表 征。测试了紫外吸收光谱、单光子荧光光谱和双光子荧光光谱。在800nm的飞秒脉 冲激光激发下,反式-4-（N-羟乙基-N'-乙基氨基）-4'-(二甲基氨基)二苯乙烯 (DMAHAS)和反式-4-(N-羟乙基-N'-乙基氨基)-4'-(二乙基氨基)二苯乙烯(DEAHAS) 均发出较强的蓝紫色上转换荧光,荧光峰分别位于436和440nm,而DMANHAS和反式- 4-[N-(乙氧基羰基-4"-硝基苯基)-N'-乙基氨基]-4'-（二乙基氨基）二苯乙烯 (DEANHAS)没有荧光。     

外围带咔唑基的联苯桥联二聚对苯乙烯撑的双光子吸收性能

报道了十字形结构对荧光生色团的双光子吸收(TPA)作用横截面积的影响. 1,4-二(9'-乙基咔唑基)- 3'-乙烯基苯(R1)是经典的具有D-π-D结构的TPA生色团. 通过一个联苯桥将两个双光吸引(TPA)链连接在一起得到的十字形分子(1)显示出比单链分子明显增大的双光子吸收作用横截面积(σ'). 在10-4 mol/L 的甲苯溶液中, 十字结构分子1的σ'值为491.0×10-50 cm4·s, 而R1的σ'值仅为137.5×10-50 cm4·s. σ'的放大可以归结为十字结构使TPA 生色团的偶极呈交叉排列, 抑制了浓溶液中的荧光猝灭.     

新型树枝分子的宽带多光子荧光发射

用飞秒Ti∶sapphire激光研究了3个树枝分子1,2,4,5-四(4-N,N-二苯氨基苯乙烯基)苯(TPAB)、1,2,4,5-四[4-N,N-二(4-溴苯基)氨基苯乙烯基]苯(TPAB-Br)和1,2,4,5-四{4-{N,N-双{4-{4-[5-(4-叔丁基苯基)-1,3,4-噁二唑-2]苯乙烯基}苯基}氨基}苯乙烯基}苯(TPAB-OXA)的多光子吸收及上转换荧光性质.在二氯甲烷溶液中3个生色团分子TPAB,TPAB-Br和TPAB-OXA在800 nm飞秒光激发的双光子荧光发射波长分别为569,535和621 nm,在1300 nm飞秒光激发的三光子频率上转换荧光发射波长分别为566,534和610 nm,采用非线性透过率法测得在四氢呋喃(THF)溶液中TPAB,TPAB-Br和TPAB-OXA在800 nm和150fs激光激发下双光子吸收截面分别为61.86×10-50,6.19×10-50和65.98×10-50 cm4.s/photon;在1300 nm和80 fs激光激发下三光子吸收截面分别为3.88×10-79,7.76×10-79和27.17×10-79 cm6.s2.树枝分子具有很强的多光子吸收和上转换荧光发射能力,多光子荧光发射波长位于500～600 nm.     

1,2,3,4-四(6,7,-二甲基苯并 唑)环丁烷光谱特性研究

本文测定并对1,2,3,4-四(6',7'-二甲基苯并 唑)环丁烷(1)及其模型化合物反-1,2-二(6',7'-二甲基苯并 唑-1',3'-基-2')乙烯(2), 1,2-二(6',7'-二甲基苯并唑-1',3'-基-2')乙烷(3), 2-甲基苯并 唑(4)的紫外吸收光谱和荧光发射光谱进行对比。研究了化合物1由于跨环共轭效应所引起的电子光谱的变化, 并从溶剂效应及晶体结构进行了探讨。     

Study of the absorption and emission spectroscopy of "A-B" type photosensitive compounds including two-photon chromophore and benzophenone moiety

"A-B" type photosensitive compounds including two-photon chromophore and benzophenone moiety have been designed, synthesized and characterized. The UV-vis absorption and fluorescence emission of the compounds have been extensively studied in various solvents. The results show that the absorption of "A-B" type compounds displays obvious double absorption bands, one of which at short-wavelength is related to the benzophenone moiety, the other at long-wavelength is mainly contributed by chromophore. The emission of "A-B" type compounds at 500-700nm shows an "unexpected" blue-shift comparing with that of the sole chromophore. The photosensitive compounds with amino group display strong emission in apolar solvents and have a low fluorescence quantum yields in polar solvents. In contrast, the compounds without amino group exhibit strong fluorescence emission in polar solvents, and low fluorescence quantum yields in apolar solvents. The fluorescence quantum yields of "A-B" type compounds are higher than those of the sole chromophore. The discoveries suggest that charge redistribution induced by the introduction of benzophenone moiety plays a key role on the absorption and emission spectroscopy.     

Novel triphenylamine-based two-photon absorption dyes including benzophenone parts

New two-photon absorption dyes including benzophenone parts,p-N,N-diphenylamino-p'-phenacylstilbene(C1),4,4-di-(4- benzoylstyrene)yltriphenylamine(C2) and 4,4',4-tri(4-benzoylstyrene)yltriphenylamine(C3),were synthesized and characterized by ~1H NMR and elemental analysis.The ratio of the molar extinction coefficients of compounds was approximately equal to the ratio of the branch amount of the compounds,namely,C1:C2:C3 was 1:2:3.Extremely high fluorescence quantum yields were detected for these compound...     

A superfluorescent fluorenyl probe with efficient two-photon absorption

The linear photophysical, excited state absorption (ESA), superfluorescence, and two-photon absorption (2PA) properties of 4,4'-(1E,1'E)-2,2'-(7,7'(1E,1'E)2,2'(4,4'-sulfonylbis(4,1-phenylene))bis(ethane-2,1-diyl)bis(9,9-didecy-9H-fluorene7,2-diyl))bis(ethane-2,1-diyl)bis(N,N-diphenylaniline) (1) were investigated in organic and aqueous media with respect to its potential application in biological imaging. The analysis of linear photophysical properties revealed a rather complex nature of the main one-photon absorption band, strong solvatochromic effects in the steady-state fluorescence spectra, single-exponential fluorescence decay, and high fluorescence quantum yields in organic solvents (≈1.0). The ESA spectra of 1 suggested potential for light amplification in nonpolar media while efficient superfluorescence in cyclohexane was demonstrated. The degenerate 2PA spectra of 1 were obtained over a broad spectral range (640-900 nm), using a standard two-photon induced fluorescence method under 1 kHz femtosecond excitation. Two well defined 2PA bands with maximum 2PA cross sections up to 1700 GM in the higher energy, short wavelength band and ≈1200 GM in the lower energy, long wavelength band of 1 were shown. The potential use of 1 in bioimaging was demonstrated via one- and two-photon in vitro fluorescence imaging of HCT 116 cells.     

反式-4,4’-二（邻甲氧基苯乙烯基）联苯化合物的合成、结构及光物理性能

以Wittig-Homer反应合成了反式对称的4,4’-二(邻甲氧基苯乙烯基)联苯化合物, X射线衍射分析测定了化合物的晶体结构. 测定了其在不同溶剂中的线性吸收光谱、荧光发射光谱及荧光量子产率. 飞秒激光做光源研究了化合物的双光子光物理性能. 测试结果表明: 该化合物在蓝光波段有较强的荧光发射, 化合物具有较高的荧光量子产率和较大的双光子吸收截面, 具有双光子诱导蓝光发射光学特性.     

Surface plasmon enhancement of two- and three-photon absorption of Hoechst 33 258 dye in activated gold colloid solution

Herein we present experimental evidence of the strong surface plasmon enhancement of two- and three-photon absorption of Hoechst 33 258 (2'-(4-hydrophenyl)-5-(4-methyl-1-piperazinyl)-2,5'-bis(1H-benzimidazole)) pentahydrate in an aqueous solution containing activated gold colloid. The 480-fold enhancement in two-photon absorption and 30-fold in three-photon absorption are predominantly attributed to the electric-field enhancement via surface plasmon resonance. The greater enhancement observed in two-photon absorption is due to the characteristic two- and three-photon absorption cross-sections of the dye.     

An exceptional red shift of emission maxima upon fluorine substitution

The effect of perfluorination on photophysical properties was investigated through synthesis and photophysical characterization of two isostructural donor-acceptor-donor dye molecules. The synthesis of two versatile fluorinated benzene compounds, 1,4-difluoro-2,5-diperfluorooctylbenzene (1) and 1,4-dibromo-2,5-difluoro-3,6-diperfluorooctylbenzene (2), is presented. The X-ray structure of 2 has been determined and shows that the perfluorinated octyl chains segregate from the benzene rings in the solid state, giving rise to a layered structure. The further synthesis through Suzuki coupling reactions using 4-formylbenzeneboronic acid with (2) and 1,4-dibromo-2,5-dioctylbenzene (3) gave, respectively, 1,4' '-diformyl-2',5'-difluoro-3',6'-diperfluorooctyl-p-terphenylene (4) and 1,4' '-diformyl-2',5'-dioctyl-p-terphenylene (5). The condensation of the dialdehydes 4 and 5 with 9,10-phenanthrenequinone and ammoniumbicarbonate in glacial acetic acid gave the dye molecules 1,4' '-bis(1H-phenanthro[9,10-d]imidazol-2-yl)-2',5'-difluoro-3',6'-diperfluorooctyl-p-terphenylene (6) and 1,4' '-bis(1H-phenanthro[9,10-d]imidazol-2-yl)-2',5'-dioctyl-p-terphenylene (7), respectively. The UV-vis spectra of the two molecules are nearly identical, whereas the fluorescence spectra are very different. Compound 7 shows blue fluorescence with little solvent dependence (lambda(emission) = 410 nm in THF, CH2Cl2, and hexane), whereas compound 6 shows a highly solvent-dependent emission wavelength (lambda(emission) = 583 nm in THF, lambda(emission) = 560 nm in CH2Cl2, and lambda(emission) = 450 nm in hexane). The fluorescence red shift of compound 6 in a series of solvents with different polarity is discussed using the Lippert-Mataga equation. Fluorescence lifetime and quantum yields were also determined. Ultraviolet photoelectron spectroscopy (UPS) was performed on thin films of compound 6 and 7 on a gold substrate. The observed ionization potential was 6.15 eV for 6 and 5.85 eV for 7" [correction].     

Photophysical characterization of a highly conjugated bipyridyl-based dye synthesized by a unique two-step approach

In this article, we present a new and simple, yet efficient, two-step approach to synthesize 4,4'-bis(dibutylaminostyrylstyryl)-2,2'-bipyridine with high yield, as well as its linear and nonlinear optical characterizations in THF and toluene solutions. We show that its one- and two-photon absorption spectra are similar in both solvents. Nevertheless, the relaxation processes of this compound exhibit dependence on the solvent polarity. The one- and two-photon induced fluorescence signal of this molecule in solution reveals that its excited state is highly stabilized in THF solution rather than in toluene. Analysis of the fluorescence quantum yield, lifetime, and radiative and nonradiative decay rates are in agreement with Lippert's model for solute-solvent interactions. The optical measurements demonstrate that this dye is a promising candidate for multiphoton fluorescence imaging, optical limiting, and dye lasers.     

Solvent effects on resonant first hyperpolarizabilities and Raman and hyper-Raman spectra of DANS and a water-soluble analog

The two-photon-resonant first hyperpolarizabilities associated with hyper-Rayleigh and hyper-Raman scattering are reported for 4-dimethylamino-4-nitrostilbene in 1,4-dioxane, dichloromethane, acetonitrile, and methanol, and for an ionic analog, 4-N,N-bis(6-(N,N,N-trimethylammonium)-hexyl)amino-4-nitrostilbene dibromide in methanol and water. Resonance Raman and hyper-Raman excitation profiles are also measured and modeled. The resonance Raman and hyper-Raman spectra show very similar relative intensities which do not vary much as the excitation frequency is tuned across the lowest-energy strong linear absorption band, suggesting that a single resonant electronic state dominates the one- and two-photon absorptions in this region. The absorption, resonance Raman, and hyper-Raman profiles can be simulated reasonably well with a common set of parameters. The peak resonant (absolute value of beta)2, measured by hyper-Rayleigh scattering, varies by about 50% over the range of solvents examined and shows a weak correlation with the linear absorption maximum, with the redder-absorbing systems exhibiting larger peak hyperpolarizabilities. The experimental hyper-Rayleigh intensities are higher than those calculated, possibly reflecting contributions from nonresonant electronic states.     

Synthesis and photophysical properties of three (multi)branched planar molecules

Three thiophenevinyl substituted one-, two-, and three-branched truxene π-conjugated compounds TS1, TS2 and TS3 have been prepared using a Heck reaction. Their linear absorption, single- and two-photon excited fluorescence were examined. The three analogues emit blue fluorescence at 420 nm. The number of branches has no influence on the position of the absorption maxima of the charge transfer band and fluorescence emitting maxima. However, the molar extinction coefficients of charge transfer band increase almost linearly with the number of branches. The two-photon absorption cross-section of the octupolar three-branched compound TS3 is several times that of the two-branched compound TS2 and one-branched compound TS1.