三苯胺类小分子的合成及其AIE性能研究

以二苯胺、碘苯、对碘甲苯以及对碘苯甲醚为原料,合成了三苯胺及其衍生物T1~T5(4-甲氧基三苯胺、4-甲基三苯胺、4-醛基三苯胺、4-乙烯基三苯胺),并对其紫外-可见吸收光谱与荧光光谱进行了检测。结果表明,连有甲氧基、甲基、乙烯基取代基的三苯胺化合物在甲醇/氯仿混合溶液中具有聚集诱导发光(AIE)性能;而醛基取代的4-醛基三苯胺表现出了聚集荧光猝灭(ACQ)现象。     

色满抗氧剂取代基效应的研究

色满抗氧剂取代基效应的研究冀亚飞，石俊英，梁启勇（安徽省药物研究所，合肥２３００２２华东化工学院专用化学品研究所，上海２００２３７）包满抗氧剂系以色满环（２Ｈ－１－苯并吡喃－３，４－二氢）为母体结构的·系列衍生物。这类衍生物具有抗氧比作用，广泛应用于...     

基于分子内旋转受限原理的线性共轭小分子的AIE性能研究

研究了6个线性共轭化合物4-丁基联苯(L1)、4,4’-二异丙基联苯(L2)、5,5’-二甲基-2,2’-联吡啶(L3)、2-([1,1’-联苯]-4-)噻吩(L4)、1,1’-联萘(L5)和5-苯基-2,2’-联噻吩(L6)的紫外-可见光谱和荧光发射光谱。结果表明,化合物L1、L2和L3均具有聚集诱导发光(AIE)性能,化合物L4、L5和L6则不具有AIE性能。该研究结果表明,二联苯(或两个简单芳杂环相连)系列化合物具有AIE性能,分子内旋转受限(RIR)是该系化合物产生AIE现象的机理。但是在二联苯的结构基础上继续增加链的长度,或者引入体积更大的芳环(萘环),化合物不再具有AIE性能。     

AIE聚硅氧烷的结构与发光性能研究

聚集诱导发光(AIE)的聚硅氧烷不含传统共轭基团,且其中的硅元素赋予了其优良的光物理性能和优异的生物相容性。近年来,我们制备了一系列含双键、羟基、胺基和环氧基的超支化和线性聚硅氧烷,发现其发光性能随结构的不同而改变,且具有一定的规律性,但对其发光机理缺乏深刻的认识。因此,探究并揭示聚硅氧烷的发光机理及结构与发光性能之间的关系具有很强的挑战性。本文综述了影响超支化聚硅氧烷发光性能的一系列因素,并利用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)对它的发光机理进行了阐释,提出了"硅桥强化发光"(SiEE)的概念。在此基础上,简述了聚硅氧烷的应用,并指出了其今后的研究方向。     

一种基于AIE机理识别Fe2+的荧光探针研究

合成了一种基于苯并噻唑衍生物的Fe~(2+)荧光探针YBTM。YBTM具有聚集诱导发光(AIE)性质,考察了YBTM在DMF/H_2O混合溶液中的荧光性质。在DMF/H_2O(1/9,v/v,HEPES 10 m M,p H=7.4)溶液中,探针YBTM对Fe~(2+)具有良好的选择性,Fe~(2+)可引起荧光猝灭,探针对Fe~(2+)响应快速,检测限为2.46×10~(-6)M。以酒石酸二铵作为掩蔽剂消除Fe~(3+)的潜在干扰。此外,探针YBTM可用于MCF-7细胞中Fe~(2+)的荧光成像。     

二苯基卡宾反应性的取代基效应

用激光闪光光解法对室温溶液中产生的三线态二苯基卡宾进行了直接观察,并通过对产生的三线态二苯基卡宾寿命的测定以及与氧气反应速率常数的考察,就邻位及对位的取代基效应进行了初步探讨。     

Mukaiyama缩合的取代基效应

合成了４－三甲硅氧基，４－苄氧基－，４－甲氧基－和４－氯苯乙酮的烯醇三甲硅醚，并使之与相应的酮以及４－氯－和４－硝基苯乙酮发生Ｍｕｋａｉｙａｍａ缩合反应，对所得羟醛的产率从取代基效应的角度进行了讨论。     

取代苯基—异喹啉基甲醇的还原和氧化反应

中药青风藤中的微量生物碱——青藤定（Ｓｉｎｏｍｅｎｄｉｎｅ）具有阿朴啡类结构［１］。在合成青藤定的过程中，需将２，３二甲氧基６溴苯基１’（５’甲氧基异喹林）甲醇（ｌａ）关环制备化合物（２）。当用光化学方法［２，３］进行中压汞灯照射下的反应时，没有得到预期产物（２）。反应后除回收原料外分离到一个Ｒｆ值较大的化合物（３）。ＩＲ谱鉴定表明化合物（３）的结构中无羟基峰。进一步的鉴定证明该化合物是原料（ｌａ）中羟基被氢原子置换的产物。结构为１（２’，３’二甲氧基６’溴苯甲基）５…     

取代基效应定量研究新进展

综述了最近20多年有机化学取代基效应定量研究所取得的诸多新进展.主要内容包括：（1）电负性均衡原理得到普遍认同并用于计算分子中电荷分布和基团的诱导效应,分子电负性计算方法在几何平均法、调和平均法、加权平均法的基础上又提出了价电子均衡方法,进一步扩展了电负性均衡原理的应用范围.（2）试剂亲电、亲核能力的实验测定,提出了以二苯甲基正离子和醌甲基化合物等作为参考化合物的标定方法,其研究范围被扩展到气相条件、有机金属反应和自由基体系,得到一系列试剂的亲核参数N和亲电参数E.理论上提出亲电性指数和亲核性指数的概念及其定量计算公式,并对实验测定参数和理论计算指数之间的关系进行了深入研究.（3）极化效应参数从最初的经验方法,进而采用量子化学方法计算,再用统计方法提出了烷基极化效应指数PEI和基团极化效应参数PEIX,被广泛用于解释和估算有机化合物的气相酸碱性、电离能、生成焓、键能、反应速率、水溶解性和色谱保留值.（4）直接由取代苯的紫外光谱吸收能量计算得到的取代基激发态参数exCC,不同于取代基在分子处于基态的极性参数和自由基状态下的自旋离域效应参数,该参数用于对位二取代苯、取代二苯乙烯、二取代氮苄叉苯胺等多类有机化合物紫外光谱的定量相关,结果良好.（5）立体屏蔽效应的提出区分了传统的三种立体效应.在羰基与亲核试剂加成反应立体选择性定量表示,提出了立体选择性指数Ci;在表示基团对反应中心表面积屏蔽的定量提出了屏蔽参数SR,进一步基于反应中心体积被屏蔽的角度提出了拓扑立体效应指数TSEI,这些参数在分子内二面角、反应的立体选择性、烯烃和烷基苯的生成焓、咪唑离子液体的酸性以及烷烃与羟基自由基的反应速率等方面得到良好的应用.此外,论文还对有机化学取代基效应定量研究中值得进一步深入探索的领域和问题提出了建议和展望.     

热活化延迟荧光蓝光小分子取代基效应的研究进展

近年来,作为第三代有机发光二极管(organic light-emitting diodes, OLED)发光材料的热活化延迟荧光(thermally activated delayed fluorescence, TADF)材料受到了学术界和产业界的广泛关注. TADF分子由于其单线态与三线态之间的能级差较小,三线态激子可以被环境热活化而通过反系间窜越上转换至单线态,理论上可实现100%的激子利用率,从而使得OLED器件外量子效率显著提高.TADF材料被认为是突破高效稳定有机电致蓝光发射瓶颈的潜在解决方案.一般, TADF分子为含有电子给体(donor, D)和电子受体(acceptor, A)的纯有机推拉电子体系.通过改变给体单元和受体单元的结构、数量和取代基及其位置可以有效调节TADF分子的单线态-三线态能级差、前线轨道分布、聚集态结构、电致发光颜色及其性能.同时取代基在调控给、受体单元的推拉电子能力及TADF材料的分子构型、聚集态结构和稳定性等物化特性方面扮演着非常重要的角色.本综述分别对D-A型和多重共振型TADF蓝光分子的取代基效应进行了综述,以期为高效稳定的蓝光TADF分...     

5,12‐Diacetyl‐5,12‐dihydroquinoxalino[2,3‐b]quinoxalines: Solid‐State Fluorescence,AIE Properties,and Orbital Switching by Substituent Effect

The compound 5,12‐diacetyl‐5,12‐dihydroquinoxalino[2,3‐b]quinoxaline 1 a and its derivatives were prepared, and their solid‐ and solution‐state spectroscopic properties were studied; 1 a shows stronger fluorescence in solution than in the solid state due to aggregation caused by self‐quenching. Phenyl‐ or alkoxy‐substituted derivatives 1 b – d show solid‐state fluorescence with moderate quantum yields of about Φ=0.12–0.15, although the corresponding values are 0.01–0.07 in solution. The spectroscopic properties of alkoxy‐substituted derivatives were hardly changed compared to 1 a and 1 b , although 1 a and 1 b have similar absorption and fluorescence maxima in solution and in the solid state. DFT calculations indicate that orbital switching occurs between HOMO and HOMO‐1 and HOMO‐2 due to orbital interactions with introduced substituents. Crystal structure analysis revealed that the molecules have bent structures around tertiary nitrogen atoms and form a characteristic dimeric structure.     

An ESIPT-Dependent AIE Fluorophore Based on HBT Derivative: Substituent Positional Impact on Aggregated Luminescence and its Application for Hydrogen Peroxide Detection

Aiming to develop the facile organic fluorophore possessing excited state intramolecular proton transfer (ESIPT) and aggregation-induced emission (AIE), we designed and synthesized two isomers with different linkage site between hydroxyl of 2-(2-hydroxyphenyl) benzothiazole (HBT) and a benzothiazole substituent (para position refers to p-BHBT and ortho position refers to o-BHBT). Fluorescence emission properties of p-BHBT and o-BHBT in THF/water mixtures with different water volume fractions indicated an opposite luminescence in aggregates, in which p-BHBT showed an ESIPT-dependent AIE properties while o-BHBT displayed ESIPT effect and aggregation-caused quenching (ACQ) qualities. A possible mechanism for molecular actions to illustrate the aggregating luminescence alteration of these two isomers had been proposed and verified by theoretical and experimental studies. More importantly, Probe-1, generated from dual ESIPT-AIE fluorophore p-BHBT, was successfully used as a ratiometric fluorescent chemosensor for highly selective (above 15-fold over other ROS) and sensitive (69-fold fluorescence enhancement with 0.22 μM of detection limit) detection of hydrogen peroxide in aqueous solution and living cells, respectively.     

Near-Infrared-Emissive AIE Bioconjugates: Recent Advances and Perspectives

Near-infrared (NIR) fluorescence materials have exhibited formidable power in the field of biomedicine, benefiting from their merits of low autofluorescence background, reduced photon scattering, and deeper penetration depth. Fluorophores possessing planar conformation may confront the shortcomings of aggregation-caused quenching effects at the aggregate level. Fortunately, the concept of aggregation-induced emission (AIE) thoroughly reverses this dilemma. AIE bioconjugates referring to the combination of luminogens showing an AIE nature with biomolecules possessing specific functionalities are generated via the covalent conjugation between AIEgens and functional biological species, covering carbohydrates, peptides, proteins, DNA, and so on. This perfect integration breeds unique superiorities containing high brightness, good water solubility, versatile functionalities, and prominent biosafety. In this review, we summarize the recent progresses of NIR-emissive AIE bioconjugates focusing on their design principles and biomedical applications. Furthermore, a brief prospect of the challenges and opportunities of AIE bioconjugates for a wide range of biomedical applications is presented.     

High‐Performance Quinoline‐Malononitrile Core as a Building Block for the Diversity‐Oriented Synthesis of AIEgens

In vivo fluorescent monitoring of physiological processes with high‐fidelity is essential in disease diagnosis and biological research, but faces extreme challenges due to aggregation‐caused quenching (ACQ) and short‐wavelength fluorescence. The development of high‐performance and long‐wavelength aggregation‐induced emission (AIE) fluorophores is in high demand for precise optical bioimaging. The chromophore quinoline‐malononitrile (QM) has recently emerged as a new class of AIE building block that possesses several notable features, such as red to near‐infrared (NIR) emission, high brightness, marked photostability, and good biocompatibility. In this minireview, we summarize some recent advances of our established AIE building block of QM, focusing on the AIE mechanism, regulation of emission wavelength and morphology, the facile scale‐up and fast preparation for AIE nanoparticles, as well as potential biomedical imaging applications.     

创新型化学实验设计:AIE超支化聚碳酸酯的合成、表征及性质研究

通过对酯化反应、酯交换反应和聚集诱导发光概念的深入介绍以及不同合成超支化聚碳酸酯方法的比较分析,引导学生理解“传统孕育创新”的文化思想。以碳酸二乙酯和丙三醇为原料,通过简单的酯交换缩聚反应设计并合成具有聚集诱导发光效应的超支化聚碳酸酯,利用紫外-可见分光光度计、荧光分光光度计分别研究超支化聚碳酸酯的紫外吸收性能和荧光性能;通过透射电镜和激光粒度仪研究超支化聚碳酸酯的聚集形貌和大小以探索发光机理。整个实验教学从科学角度出发,从合成原理和发光机理的教学理论中让学生理解“传统孕育创新”的文化内涵,不仅可以培养学生对科研的热情和兴趣,还可以让学生掌握先进仪器的操作技能,培养学生综合实验能力和人文素养。     

卤代甲烷的键离解能与取代基效应

将芳环上取代基的电子效应参数引入卤代甲烷, 以卤代甲烷分子Y-CH_nX_{3－n (n＝0～3; Y＝H, F, Cl, Br, I; X＝F, Cl, Br, I)中Y-C键的标准键焓 与中心C原子相键连原子的场/诱导效应之和ΣFi、共轭效应之和ΣRi以及诱导偶极之和Σ(α×F)为参数, 建立了一个定量估算卤代甲烷分子中Y-C键离解能(BDE)的通用模型, BDE(Y-C)＝57.5460＋0.8855 －101.0780ΣRi－64.8390ΣFi－10.1034Σ(α×F). 对35个C-H, C-F, C-Cl, C-Br和C-I键回归分析结果表明, 估算Y-C键离解能的精度在实验误差范围内. 对外部数据集的预测结果表明, 该模型具有较高的预测精度, 可用于预测还没被实验测定的卤甲烷中Y-C键离解能. 还对卤代甲烷中104个C-Y键的键离解能进行了预测. 将芳环上取代基效应用于研究饱和体系化学键性能, 有利于深入理解取代基效应对化学键性能的影响.}     

1-二茂铁基-3-芳基-2-丙烯酮紫外光谱的取代基和溶剂效应

测定了 6个 1-二茂铁基 - 3-芳基 - 2 -丙烯酮在 11种有机溶剂中的紫外光谱 ,其紫外光谱的最大吸收峰频率νuvmax与哈密特亲电取代基常数σ+ p 之间呈良好的线性关系 ,与溶剂的极性参数XR 之间也呈较好的线性关系 .     

Remote Effect from Boron Cluster: Tunable Photophysical Properties of o-Carborane-Based Luminogens

We proposed a new molecular design strategy that the o-carboranyl group is attached as “an innocent unit” to the remote side of luminogens to tune photophysical properties. To verify this strategy, two o-carborane-based compounds with asymmetric molecular geometry were designed and synthesized. Photophysical properties of o-carborane-based luminogens were investigated on the basis of UV-Vis spectra, photoluminescence spectra, crystal structure analysis and theoretical calculations. The results indicate that the o-carboranyl group has a slight effect on the energy gap between the ground state (S₀) and the first excited state (S₁) in the solution state but a significant effect on the energy gap between S₀ and S₁ in the solid state. Besides, the radiative and non-radiative transition processes are modulated by the o-carboranyl unit. This leads to emission quenching in the solution state but an enhanced luminous efficiency in the aggregate state with a typical aggregation-induced emission (AIE) property.     

Substituent Effect on N-Benzylideneanilines by DFT Energy Partition

To investigate the substituent effect on x-electron delocalization of the N-benzylideneaniline （NBA）, the vertical resonance energies △E^V（θ） of eleven substituted NBAs were separated into n and a parts at the B3LYP/6-311G（d） level of the Density Functional Theory （DFT）. When substituted with an electron-releasing group --OH, the calculated △E^V（θ） of NBA was increased, indicative of more resonance destabilization than the mother molecule. However, when substituted with an electron-withdrawing group -NO2, the calculated △E^V（θ） values indicated less resonance destabilization. The most destabilizing effect was observed especially when the -OH group located at the ortho-position of the aromatic ring in the fragment -N=CH-Ar. For most of the substituted NBA molecules, it was the destabilized a framework that determined the destabilizing feature of the vertical resonance energy, instead of the stabilized n system. When the -NO2 substituent at the para-position of the aromatic ring of the -N=CH-Ar group, the π system had the highest stabilizing effect while the σ framework exhibited the highest destabilizing effect. While the -NO2 substituent was at the para-position of the left aromatic ring （At-）, the NBA had the least vertical resonance energy value.     

高效近红外聚集诱导发光纳米粒子用于生物成像的研究

基于荧光共振能量转移机理（FRET）,利用两亲性聚合物Pluronic F-127共包覆两种聚集诱导发光（Aggregation-induced Emission,AIE）材料TPABDFN和TPE-Me,制备了高效近红外发射TPABDFN/TPE-Me@F127纳米粒子.实验表明,这种聚合物纳米粒子具有很大的斯托克斯位移和较高的荧光量子效率,很好的单分散性、稳定性,以及较好的生物相容性和低的细胞毒性,对HepG2细胞进行荧光生物成像,得到很好的细胞成像效果.