Lutetium complexes with the 1,3-diphenylcyclopentadienyl ligand. Syntheses and molecular structures of the complexes {(Ph2C5H3)Lu(C2Ph4)(THF)} and {(Ph2C5H3)LuCl2(THF)3}

The reaction of LuCl₃(THF)₃ with Na(1,3-Ph₂C₅H₃) followed by the in situ reaction with Na₂[Ph₄C₂] produced (1,3-Ph₂C₅H₃)Lu(Ph₄C₂)(THF) (1). The structure of 1 was established by X-ray diffraction. In the crystal structure of 1, the bis-allyl η⁶-coordination of the tetraphenylethylene dianion to the lutetium cation was observed. The structures of (1,3-Ph₂C₅H₃)LuCl₂(THF)₃ and (C₅H₅)LuCl₂(THF)₃ were determined by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1912–1918, October, 2007.     

4,4'-[(2,2-二苯乙烯)-1,1-双(4,1-亚苯基)]二吡啶的合成、表征及其聚集诱导发光性能研究

以提升学生的实验操作及创新能力为目的的综合化学实验，采用简单的2步法（缩合和Suzuki反应）合成了一种具有聚集诱导发光性能的化合物4，4'-[（2，2-二苯乙烯）-1，1-双（4，1-亚苯基）]二吡啶（简称2Py-TPE）。利用过滤、洗涤、萃取、干燥和柱层析等常用的有机分离操作手段对该化合物进行纯化；使用核磁共振仪、高分辨质谱仪、红外光谱仪及稳态瞬态荧光光谱仪对其进行结构表征和聚集诱导发光性能研究。该实验不仅可以促使学生了解以四苯乙烯衍生物为代表的聚集诱导发光材料的研究现状，而且能够培养学生的综合实验能力和科学探究能力。     

基于六苯基苯骨架四苯基乙烯衍生物的合成及聚集诱导发光性质研究

设计合成了三个基于六苯基苯骨架结构的四苯基乙烯衍生物HPB-nTPE (n=2, 4, 6), 它们的分解温度均在440 ℃以上, 具有很好的热稳定性. 研究了化合物的均相溶液、聚集体以及固体粉末的光物理性质. 该类化合物具有典型的聚集诱导发光性质, 在均相溶液中几乎不发光, 而形成聚集体后发出明亮的蓝绿色荧光, 荧光量子产率分别为0.37, 0.36和0.37, 与均相溶液中相比增强了400多倍. HPB-nTPE固态呈无定形结构, 荧光量子产率分别为0.39, 0.36和0.36, 约为固态四苯基乙烯的1.8倍. HPB-nTPE的聚集态和固态的高发光量子产率来自两方面的贡献, 一是凝聚态抑制了四苯基乙烯基团中苯环的自由旋转引起的激发态非辐射跃迁, 另一方面是星形刚性六苯基苯骨架进一步抑制了凝聚态分子内和分子间四苯基乙烯基团π-π堆积引起的激发态非辐射跃迁过程, 从而提高了四苯基乙烯基团的辐射跃迁效率. 本研究对高效有机光功能材料的发展有重要意义.     

压力和酸响应的四苯乙烯修饰喹喔啉类荧光染料的合成与性质研究

合成了新的给受体型四苯乙烯修饰的喹喔啉衍生物BTPQ、DBTPQ和BTBQ.三个化合物表现出不同程度的聚集诱导发光(AIE)行为,当BTBQ (四苯乙烯单元修饰在喹喔啉的2,3-位)的四氢呋喃溶液中含水量达到90%时,其荧光发射强度增加至原来的54倍.此外,固体BTBQ在三氟乙酸蒸气作用下可由淡黄色变成红色,且其蓝绿色荧光被显著猝灭,可见,它可作为传感材料用于酸蒸气的可视化检测.由于连接在喹喔啉5,8-位上的四苯乙烯单元的空阻作用导致BTPQ和DBTPQ不易被质子化,因此,二者对酸不敏感,但是,它们的固态发光颜色在研磨前后发生了明显变化,如,BTPQ在结晶态时发射蓝色荧光,经研磨变成无定形态后,发射蓝绿色荧光, BTPQ和DBTPQ的压致荧光变色行为在研磨、加热/溶剂熏蒸处理下具有可逆性.     

In Situ Monitoring of RAFT Polymerization by Tetraphenylethylene‐Containing Agents with Aggregation‐Induced Emission Characteristics

A facile and efficient approach is demonstrated to visualize the polymerization in situ. A group of tetraphenylethylene (TPE)‐containing dithiocarbamates were synthesized and screened as agents for reversible addition fragmentation chain transfer (RAFT) polymerizations. The spatial‐temporal control characteristics of photochemistry enabled the RAFT polymerizations to be ON and OFF on demand under alternating visible light irradiation. The emission of TPE is sensitive to the local viscosity change owing to its aggregation‐induced emission characteristic. Quantitative information could be easily acquired by the naked eye without destroying the reaction system. Furthermore, the versatility of such a technique was well demonstrated by 12 different polymerization systems. The present approach thus demonstrated a powerful platform for understanding the controlled living radical polymerization process.     

Migratory Shift in Oxidative Cyclodehydrogenation Reaction of Tetraphenylethylenes Containing Electron‐Rich THDTAP Moiety

Four tetraphenylethylenes ( 2 a – d ) containing an electron‐rich 2,3,4,6‐tetrahydro‐1,6‐dithia‐3a‐azaphenalene (THDTAP) moiety have been synthesized. The 2 a – d show aggregation‐induced emission (AIE) with yellowish green photoluminescence (PL) in THF‐H₂O (v/v, 1:9) solution and in the solid state. Compounds 2 a – d undergo 1,2‐migratory shift in oxidative cyclodehydrogenation reactions to afford the unexpected products 3 a – d which display green PL in CH₂Cl₂ solution and are non‐emissive in the solid state. The PL intensities of 3 a – d are clearly enhanced in the presence of meta‐chloroperoxybenzoic acid (mCPBA) owing to the oxidation of the S‐atoms on the THDTAP moiety. In contrast, the PL of 2 a – d in THF‐H₂O (v/v, 1:9) solution is quenched by adding mCPBA, ascribable to the oxidation of the C=C bond on the ethylene moiety. It is found that the absorption of 3 a – d is distinctly red‐shifted from the UV/Vis region to the NIR region upon acidification, arising from the protonation of the N‐atom on the THDTAP moiety. Furthermore, 3 a – d display nonlinear optical response (NLO) and optical limiting (OL) behaviour which is superior to that of the well‐known OL material C₆₀.     

Water‐soluble Glucosamine‐coated AIE‐Active Fluorescent Organic Nanoparticles: Design,Synthesis and Assembly for Specific Detection of Heparin Based on Carbohydrate–Carbohydrate Interactions

Two water‐soluble carbohydrate‐coated AIE‐activate fluorescent organic nanoparticles TPE3G and TPE4G were designed and synthesized for the detection of heparin. Different from the reported strategy, we not only utilized the general detection mechanism of electrostatic interactions, but also introduced the concept of carbohydrate‐carbohydrate interactions (CCIs) to enrich the detection mechanism of heparin. TPE3G can serve as an efficient “turn‐on” probe with higher selectivity towards heparin than TPE4G . TEM studies revealed that the micro‐aggregated TPE3G was encapsulated with the heparin chain to form a complex self‐assemblied composite and emits strong fluorescence. It is believed that the results illustrated in this study provide a novel strategy based on CCls to design water‐soluble and more efficient bio‐probes for various biological and clinical applications.     

Supramolecular Assembly of TPE-Based Glycoclusters with Dicyanomethylene-4H-pyran (DM) Fluorescent Probes Improve Their Properties for Peroxynitrite Sensing and Cell Imaging

Two red-emitting dicyanomethylene-4H-pyran (DM) based fluorescent probes were designed and used for peroxynitrite (ONOO⁻) detection. Nevertheless, the aggregation-caused quenching effect diminished the fluorescence and restricted their further applications. To overcome this problem, tetraphenylethylene (TPE) based glycoclusters were used to self-assemble with these DM probes to obtain supramolecular water-soluble glyco-dots. This self-assembly strategy enhanced the fluorescence intensity, leading to an enhanced selectivity and activity of the resulting glyco-dot comparing to DM probes alone in PBS buffer. The glyco-dots also exhibited better results during fluorescence sensing of intracellular ONOO⁻ than the probes alone, thereby offering scope for the development of other similar supramolecular glyco-systems for chemical biological studies.     

Triphenylamine,Carbazole or Tetraphenylethylene-Functionalized Benzothiadiazole Derivatives: Aggregation-Induced Emission (AIE), Solvatochromic and Different Mechanoresponsive Fluorescence Characteristics

The development of mechanochromic fluorophors with high-brightness, solid-state fluorescence is very significant and challenging. Herein, highly solid-state emissive triphenylamine, carbazole and tetraphenylethylene-functionalized benzothiadiazole derivatives were developed. These compounds showed remarkable aggregation-induced emission and solvatochromic fluorescence characteristics. Furthermore, these fluorogenic compounds also displayed different mechanically triggering fluorescence responses.     

Tunable fluorescence conjugated copolymers consisting of tetraphenylethylene and fluorene units: From aggregation‐induced emission enhancement to dual‐channel fluorescence response

A series of new conjugated polymers PTPE_xF_y, which consist of tetraphenylethylene (TPE) units and fluorene (F) units, have been designed and synthesized by Suzuki cross‐coupling polymerization. The polymers PTPE_xF_y exhibited aggregation‐induced emission enhancement and dual‐channel fluorescence response (DCFR) when they were aggregated in solution, and these properties are related with their TPE‐to‐F ratio in the polymer backbone. For PTPE and PTPE_0.5F_0.5 , the fluorescence emission was enhanced by aggregation when water was added into their THF solutions. For the copolymers PTPE_0.3F_0.7 , PTPE_0.2F_0.8 , and PTPE_0.1F_0.9 , the DCFRs were observed when they were aggregated by adding water into their solution, which can be attributed to the different responses of fluorene segments and TPE segments to aggregation. The fluorene segments have an aggregation‐caused quenching characteristic, whereas the TPE segments have an aggregation‐induced emission characteristic. According to the fluorescence lifetime and quantum yield data of the polymer solutions, we have discovered that the polymer's natural life time increases as its TPE content increases. In the solid film, PTPE_0.3F_0.7 and PTPE_0.2F_0.8 showed better quantum yield than other polymers, due to the combination of the excellent fluorescent property of the fluorene groups and the nonplanar conformation of the TPE groups. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013