新型双发色团固体激光染料薄膜的光稳定性研究

利用UV-Vis吸收光谱仪和光化学反应器研究了新型双发色团固体激光染料薄膜的光降解动力学.研究结果表明:双发色团固体激光染料薄膜的光褪色反应遵循假一级动力学衰减.在PRNAM系列共聚物(N-烯丙基-若丹明1、N-[(2-丙烯酸基)乙基]-1,8-萘酰亚胺和甲基丙烯酸甲酯的共聚物)中萘酰亚胺基团通过聚合物碳链与若丹明基团的氮原子相连;而在PRNM系列共聚物(若丹明1的烯丙基酯、N-[(2-丙烯酸基)乙基]-1,8-萘酰亚胺和甲基丙烯酸甲酯的共聚物)中则是与若丹明基团的酯基相连.PRNAM系列共聚物的光稳定性优于PRNM和PRM(若丹明1的烯丙基酯和甲基丙烯酸甲酯的共聚物)系列的光稳定性.     

三元若丹明激光染料荧光寿命研究

利用单光子计数技术测试了新型三元若丹明激光染料在不同溶剂中的荧光寿命、荧光光谱及其寿命的实验数据.实验表明,所研究的三元若丹明染料存在着有效的分子内能量传递过程,这些过程使得激光染料的荧光量子效率及光稳定性明显改善.     

新型以若丹明染料为母体的三发色团化合物的荧光性能

若丹明染料作为一种重要的激光染料,它们具有较高的荧光量子效率。这类染料在紫外区的吸收是相当小的,于是,当它们被使用在横向泵浦激光装置上时,就需要相当高的染料浓度,这样才能有效地吸收紫外泵浦光(如XeCI激光器,308 nm)。问题是,这类染料的发射光谱与其吸收光谱的低能量部分有重叠,亦即它门的Stokes位移较小,并且由于染料的荧光量子效率通常小于100,以致使一部分染料的激发辐射被基态染料分子再吸收,从而导致激发辐射的损失。与此同时,为了有效吸收泵浦光能量,染料的浓度通常很高,这样,激发辐射损失就会相当大。     

FRET-based sensor for imaging chromium(III) in living cells

On the basis of fluorescent resonance energy transfer from 1,8-naphthalimide to rhodamine, a fluorophore dyad (FD8) containing rhodamine and a naphthalimide moiety was synthesized as a Cr3+-selective fluorescent probe for monitoring Cr3+ in living cells with ratiometric fluorescent methods.     

Synthesis and functional properties of green fluorescent poly(methylmethacrylate) for use in liquid crystal systems

The copolymerization of six 4-aminosubstituted-1,8-naphthalimide dyes comprising an allylic polymerizable group with methylmethacrylate has been investigated. The utility of the copolymers prepared as fluorescent component in polymer/liquid crystal systems has been examined. The photophysical and photochemical properties of the systems monomeric dye/liquid crystal and copolymer/liquid crystal have been also discussed. It has been shown that in a liquid crystal mixture 1,8-naphthalimide dyes and respective copolymer/liquid crystals have yellow–green fluorescent color with good photostability. Copyright © 2003 John Wiley & Sons, Ltd.     

新型三嗪桥连的双1,8-萘酰亚胺衍生物的合成及其光物理行为

以1,8-萘酰亚胺和三聚氯氰为主要原料, 合成了两种由三嗪环桥连的双1,8-萘酰亚胺化合物3 和5. 采用紫外-可见光谱和荧光光谱等手段考察了两种化合物在不同溶剂中的光物理行为. 与参比化合物N-丁基-1,8-萘酰亚胺相比, 在二氯甲烷、三氯甲烷和甲醇等极性溶剂中, 化合物3和5除了在短波区(λ<400 nm)存在1,8-萘酰亚胺的特征荧光发射峰外, 在长波区(>450 nm)均产生一个较强的新荧光发射峰, 表现出分子内激基缔合物的光物理行为. 与化合物5相比, 由于化合物3特殊的构象异构, 其荧光强度发生严重的猝灭. 在非极性溶剂甲基环己烷中, 化合物5 由于存在较强的分子间氢键作用而聚集, 受激后形成了较稳定的分子间激基缔合物, 但未观察到明显的分子内激基缔合物的形成. 在甲苯溶剂中, 化合物3和5与甲苯分子形成了激基复合物, 并未形成分子内激基缔合物. 进一步研究3和5的固态激发态性质, 发现化合物3和5的固体薄膜受激后分别在465和469 nm处出现激基缔合物的特征荧光发射峰.     

新型可聚合双发色团电致发光材料的合成

自１９８７年Ｔａｎｇ［１］报道了高效、高亮度的双层有机薄膜电致发光器件以来,电致发光材料的研究受到了广泛的关注．接着在１９９０年,英国剑桥大学Ｂｕｒｏｕｇｈｅｓ等［２］首次利用聚亚苯基乙烯（Ｐｏｌｙ（ｐ ｐｈｅｎｙｌｅｎｅｖｉｎｙｌｅｎｅ）,ＰＰＶ）...     

Synthesis and near-infrared characteristics of novel perylene bisimide dyes bay-functionalized with naphthalimide chromophores

Novel perylene bisimide dyes bay-functionalized with naphthalimide chromophores have been prepared conveniently by coupling of 1,8-naphthalimide and dibromoperylene bisimides. Their optical properties were investigated by UV-vis and fluorescence spectroscopy. The absorption spectra of these compounds showed wide spectral responses from 300 to 700 nm,which would be potentials for application as organic solar cells.     

含萘酰亚胺光功能基元的吡唑啉酮席夫碱的合成及其光谱性质

以4-溴-1,8-萘酐为原料,经亚胺化、取代和还原反应合成了中间体N-对氨基苯基-4-哌啶-1,8-萘酰亚胺(4),4与1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5缩合得到一种含萘酰亚胺光功能基元的的新型吡唑啉酮席夫碱——1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5缩N-对氨基苯基-4-哌啶-1,8-萘酰亚胺(6)。4和6的结构经1H NMR和IR确证。研究了6在不同溶剂中的光谱性质,发现其吸收光谱和荧光光谱随溶剂的极性不同而表现出不同的光谱特性。进一步研究表明6在不同溶剂中可能以不同的互变异构体存在。     

Mechanisms of photoinitiated cleavage of DNA by 1,8-naphthalimide derivatives.

Using water-soluble 1,8-naphthalimide derivatives, the mechanisms of photosensitized DNA damage have been elucidated. Specifically, a comparison of rate constants for the photoinduced relaxation of supercoiled to circular DNA, as a function of dissolved halide, oxygen and naphthalimide concentration, has been carried out. The singlet excited states of the naphthalimide derivatives were quenched by chloride, bromide and iodide. In all cases the quenching products were naphthalimide triplet states, produced by induced intersystem crossing within the collision complex. Similarly, the halides were found to quench the triplet excited state of the 1,8-naphthalimide derivatives by an electron transfer mechanism. Bimolecular rate constants were < 10(5) M-1 s-1 for quenching by bromide and chloride. As expected from thermodynamic considerations quenching by iodide was 6.7 x 10(9) and 8.8 x 10(9) M-1 s-1 for the two 1,8-naphthalimide derivatives employed. At sufficiently high ground-state concentration self-quenching of the naphthalimide triplet excited state also occurs. The photosensitized conversion of supercoiled to circular DNA is fastest when self-quenching reactions are favored. The results suggest that, in the case of 1,8-naphthalimide derivatives, radicals derived from quenching of the triplet state by ground-state chromophores are more effective in cleaving DNA than reactive oxygen species or radicals derived from halogen atoms.     

Photo-stability of yellow-green emitting 1,8-naphthalimides containing built-in s-triazine UV absorber and HALS fragments and their acrylonitrile copolymers

Two novel 1,8-naphthalimide dyes, containing active fragments of both 2-(2-hydroxyphenyl)-1,3,5-triazine UV absorber and 2,2,6,6-tetramethylpiperidine radical scavenger as well as a polymerisable allyl group, were designed as multifunctional yellow-green emitting fluorophores capable simultaneously of chemically fluorescent dyeing and photo-stabilisation of polymers. Their basic photo-physical characteristics have been determined and are discussed. It was shown that combination of different structural units in the 1,8-naphthalimide molecule does not result in their interaction through intramolecular fluorescence quenching due to an electronic energy transfer. The ability of the combined dyes to copolymerise with acrylonitrile was demonstrated as polyacrylonitriles stable to solvents and with an intense colour and fluorescence were obtained. Photo-degradation of the new fluorophores and their influence on the photo-stability of the coloured copolymers have been studied and compared to other similar fluorescent dyes, not containing either UV absorber or hindered amine fragment in their molecules as well as not containing both of them. Novel fluorophores showed the best photo-stability in both solution and polymer. A significant photo-stabilising effect towards photo-destruction of polyacrylonitrile was found, which might be caused by a possible “synergism” of two stabiliser fragments differing in their action.     

Multifunctional photo acid generator for fluorescence imaging based on self-contained photoreaction

We present N-(p-anilinesulfonyloxy)-1,8-naphthalimide (ASNI) as fluorescence imaging material based on a novel fluorescence imaging mechanism. ASNI is composed of two functional moieties in one molecule: an acid-reactive fluorescence probe and a photoacid generator (PAG). When ASNI is photoirradiated, a bond in the PAG moiety breaks and an acid is generated. The fluorescence probe moiety then detects the acid and fluoresces. We call this novel mechanism a self-contained photoreaction (SCP). The photophysical properties and photoreactivity of ASNI were measured and compared with those of a prototype PAG, N-(phenylsulfonyloxy)-1,8-naphthalimide. These were well represented by density functional theory calculations. SCP permits one-step fluorescence imaging without any wet or dry developing process.     

Synthesis and tunable emission of novel polyfluorene co-polymers with 1,8-naphthalimide pendant groups and application in a single layer-single component white emitting device

New luminescent polymers containing two individual emission species-poly(fluorene-alt-phenylene) as a blue host and variable amounts of 1,8-naphthalimide as red dopant have been designed and synthesized. Optical studies (optical absorption (OA) and steady-state photoluminescence emission (PL)) in diluted solutions and thin solid films reveal that the emission spectrum can be tuned by varying the content of 1,8-naphthalimide moieties. Although no significant interaction can be observed between both moieties in the ground state, after photoexcitation an efficient energy transfer takes place from the PFP backbone to the red chromophore, indeed, by adjusting the polymer/naphthalimide ratio it is possible to obtain single polymers which emit white light to the human eye in solid state. Energy transfer is more effective in the co-polymers than in physical mixtures of the two chromophores. We prepared single-layer electroluminescent simple devices with structure: ITO/poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT:PSS)/active layer/Ba/Al. With this single layer-single component device structure, white light with Commission Internationale de l’Eclairage (CIE) color coordinates (0.3, 0.42) is obtained for the electroluminescence (EL) emission with an efficiency of 22.62 Cd/A.     

Different Steric‐Twist‐Induced Ternary Memory Characteristics in Nonconjugated Copolymers with Pendant Naphthalene and 1,8‐Naphthalimide Moieties

Herein, novel random copolymers PMNN and PMNB were designed and synthesized, and the memory devices Al/ PMNN and PMNB /ITO both exhibited ternary memory performance. The switching voltages of the OFF–ON1 and ON1–ON2 transitions for both memory devices are around −2.0 and −3.5 V, respectively, and the ON1/OFF, ON2/ON1 current ratios are both up to 10³. The observed tristable electrical conductivity switching could be attributed to field‐induced conformational ordering of the naphthalene rings in the side chains, and subsequent charge trapping by 1,8‐naphthalimide moieties. More interestingly, by adjusting the connection sites of 1,8‐naphthalimide moieties to tune the steric‐twist effect, different memory properties were achieved ( PMNN showed nonvolatile write once, read many (WORM) memory behavior, whereas PMNB showed volatile static RAM (SRAM) memory behavior). This result will offer a guideline for the design of different high‐performance multilevel memory devices by tuning the steric effects of the chemical moieties.     

Synthesis and fluorescence of N-substituted-1,8-naphthalimides

A number of novel N-substituted-1,8-naphthalimides have been prepared and their fluorescence yields measured in water at pH 7.4. The type of substitutent and the substitution pattern on the naphthalimide nucleus produce markedly different fluorescence yields, (quantum efficiencies, ø varying from ø = 0-0037 for N-(3-N'-morpholino-1-propyl)-4-amino-3-methoxy-1,8-naphthalirnide (7) to ø = 0–77 for N-(3-bromopropyl)-4-acetamido-1,8-naphthalimide (31).     

Methacrylate-tethered analogs of the laser dye PM567--synthesis,copolymerization with methyl methacrylate and photostability of the copolymers

The synthesis and characterization of new analogs of the laser dye PM567 (4,4-difluoro-1,3,5,7,8-pentamethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indacene) with the 8-position substituted by a linear chain with n methylenes (n = 1, 3, 5, 10 or 15) tethered with an acetoxy or methacryloyloxy group (PnAc and PnMA, respectively) is described. The monomeric dyes PnMA have been successfully copolymerized with methyl methacrylate (MMA), yielding linear copolymers of high optical quality where the covalently bonded chromophore is separated from the polymeric main chain by a spacer of variable length. The photostability of the solid polymeric materials under UV (310 nm) irradiation (method ASTM G 53-77) has been compared with those of the model dyes PnAc and PM567 as solid solutions in poly-MMA (PnAc-PMMA and PM567-PMMA, respectively). In all the cases, the chromophore bound to the polymer is more photostable than that simply dissolved in the same polymer, with photodegradation quantum yields in the range 2.3 x 10(-5) to 4.8 x 10(-5), which was interpreted as due to additional modes for the dissipation of the absorbed energy along the polymeric chain. In both polymer solutions and copolymers, the length of the polymethylene chain has low or null influence on the photostability. In ethanol solution, PnAc model dyes with polymethylene chains with three or more methylene groups show about the same photostability; this is of an order of magnitude higher than that of the parent dyes P1Ac and PM567 in the same solvent.     

基于1,8-萘酰亚胺与罗丹明B间荧光共振能量转移的高选择性Hg2+比率荧光探针

以罗丹明B与1,8-萘二甲酰亚胺反应合成了1个高选择性Hg²⁺比率荧光探针(RN). 在甲醇/乙腈/4-羟基哌嗪乙磺酸缓冲溶液(pH=7.2, 体积比8:1:1)中, RN对Hg²⁺具有比色和比率荧光双重响应. 加入Hg²⁺后, RN的紫外-可见光谱在约556 nm处产生强吸收, 溶液由浅绿色变为橙色, 其它金属离子对RN的紫外-可见光谱几乎无影响. 无Hg²⁺存在时, RN的荧光光谱在540 nm处出现萘二甲酰亚胺荧光团的特征峰; 加入Hg²⁺后, 540 nm处的发射带逐渐消失, 同时在580 nm附近产生强荧光, 荧光颜色从绿色变为橙色. 这归因于从萘酰亚胺到开环罗丹明B的荧光共振能量转移(FRET), 探针RN对Hg²⁺的比率荧光响应具有高选择性, 不受其它共存金属离子的干扰.     

Photodegradation of poly(amidoamine) dendrimers peripherally modified with 1,8-naphthalimide units

This paper presents the photophysical and photochemical characteristics of four new poly(amidoamine) dendrimers of zero and second generation whose periphery has been modified with 1,8-naphthalimide units. Nitro- and allylamino groups have been used as substitutents at the C-4 position of the 1,8-naphthalimide fluorophores. The discussion is focused on the photodegradation of the dendrimers in N,N-dimethylformamide and dioxan solutions. Investigations have shown that the photodegradation of the dendrimers with 4-nitro substituted 1,8-naphthalimide proceed with yellow colour development in the solvent while no colour changes followed the same process in dendrimers with allylamino group substituent. The results also show that the photostability of the dendrimers depends on their generation.     

Anchoring of 1,8-naphthalimide derivative into mesoporous MCM-41 molecular sieves

The fluorescent dye molecules, 4-piperidine-1,8-naphthalimide, were successfully fixed into the amino modified pore channel of mesoporous MCM-41 type materials by in situ reaction of 4-piperidinyl-1,8-naphthalic anhydride with the amino group. The formation of amide bonds on the pore surface was verified by infrared spectra. The maximum fluorescence emission peak of this hybrid material has a red shift of 13 nm compared to that of a naphthalimide derivative in ethanol solution. Moreover, the fluorescence intensity of dye molecules grafted into Ce-doped MCM-41 is higher than that in pure silica MCM-41. This phenomenon is attributed to the inhibited internal electron transfer from piperidine to naphthalimide groups by Ce⁴⁺, thus improving the fluorescence intensity of the naphthalimide group. The unique fluorescence behavior of the 1,8-naphthalimide derivative doped hybrid mesoporous material makes it a good candidate for the metal ions microdetection.     

New Fluorescent Conjugates of Uridine Nucleoside and Substituted 1,8-Naphthalimide: Synthesis, Weak Interactions and Solvent Effects on Spectra

Summary.  Novel fluorescent conjugates of uridine nucleoside and 4-dimethylamino-1,8-naphthalimide via linkage with different length, and their precursors were synthesized. Their spectroscopic properties were examined in ten different solvents. It was found that the spectroscopic properties for these conjugates are strongly dependent on polarity and hydrogen bonding ability of solvents. Their fluorescence spectra are also strongly influenced by intramolecular aromatic stacking and hydrogen bonding between the base or sugar moiety of the uridine nucleoside and naphthalimide moiety, which is controlled by the length of the linker. Corresponding author. E-mail: xhqian@dlut.edu.cn; xhqian@ecust.edu.cn Received May 27, 2002; accepted (revised) July 16, 2002