苯乙烯马来酸酐共聚物(SMA)化学改性制备荧光聚合物及其荧光性能研究

用自行合成的 2-氨基噻唑 (1)、2-氨基-4-苯基噻唑 (2)、2-氨基苯并噻唑(3)等荧光小分子化合物,与商品化的苯乙烯马来酸酐共聚物 (SMA)中的酸酐基团反应,制成聚苯乙烯马来酰亚胺 (SMI),实现了SMA化学改性.在获得荧光聚合物的同时,不仅保持了原SMA的可溶性、成膜性等优点,其热性能也得到了改善.通过示差扫描量热 (DSC)、凝胶色谱 (GPC)、红外、紫外及荧光光谱等手段表征了荧光聚合物的玻璃化转变温度、分子量及结构与荧光性能关系.     

高度可溶聚苝酰亚胺材料的合成及性能研究

聚酰亚胺是一类具有优异综合性能的聚合物材料 [1,2 ] .近年来 ,合成含荧光染料的可溶性聚酰亚胺材料在聚合物化学领域引起了广泛兴趣 [3～ 11] ,人们期望这类聚合物材料会比其小分子材料具有更加优越的性能 .小分子酰亚胺荧光染料具有极高的荧光量子效率、光化学和热稳定性 ,可广泛应用于光学开关[12 ] 、电致发光器件 [13,14 ] 和太阳能转换器 [15] 等领域 ,但是由于的大π键平面共轭结构 ,使得材料的溶解性能极差 ,难以加工 .最近 ,本实验室通过合成含叔丁基的芳香二胺 [4,4′-亚甲基双 ( 2 -叔丁基苯胺 ) ]与各种芳香四酸二酐反应…     

丙烯酸全氟烷基乙基酯嵌段共聚物的组成结构表征

含氟聚合物具有独特的性质 ,使其成为高分子材料领域中的特殊功能材料 .这类聚合物具有高表面活性、高热稳定性、高化学稳定性 ,及既憎水又憎油的“三高”、“两憎”特性[1] ,可用作织物拒水拒油整理剂、防污涂料、流平剂等 .然而含氟单体价格高昂 ,人们希望在满足性能要求的同时 ,尽量减少氟单体的用量 .利用分子设计方法 ,制备结构规整的嵌段共聚物无疑是一种有效的方法 .目前 ,文献中关于含氟嵌段共聚物的制备的方法有负离子聚合法[2 ] 、基团转移聚合法 (GTP) [3 ] 、正离子聚合法[4] 、引发 转移 终止法 (Iniferter) [5] ,以及近年…     

超支化聚(酯-酰胺)的合成与流变改性研究

近十几年来 ,超支化聚合物因具有独特的结构和特殊的性能而受到普遍关注[1] .超支化聚合物具有低的熔体粘度 ,与线性聚合物共混可显著改善其加工流变性 ,具有商业应用潜力 .关于超支化聚合物在流变改性方面的应用已有文献报道[2～ 6] ,但目前文献中的大多数单体合成较繁琐且收率不高 ,这已成为制约超支化聚合物应用的瓶颈 ,如何以简便的途径合成超支化聚合物已成为当前研究的重点 .本文设计一条新的合成路线 ,即以 1 ,2 ,4 苯三酸酐、乙醇胺及乙酸酐为原料 ,以高的收率得到了单体N ( 2 乙酰氧基乙基 ) N ( 2′ ,4′ 二羧基苯甲酰基 )胺 (…     

脂肪型超支化聚酯的端基改性研究

近年来 ,超支化聚合物以其独特的结构和性能而受到广泛的重视 ,已成为 2 1世纪高分子科学研究的重要方向[1～ 4 ] .超支化聚合物通常是通过 AB2 型单体的缩聚来合成的 ,由于超支化聚酯的单体容易合成 ,因此 ,有关超支化聚酯的研究最为深入 .目前所报道的脂肪型超支化聚酯都是以 2 ,2 -二甲醇基丙酸为原料来合成的 ,Malstrom等 [5～ 7]系统研究了该聚合物的合成及结构 .最近 ,Johansson[8]采用丙烯酰氯对该聚合物端基改性 ,获得了可用于紫外光固化的涂料 ,但是所采用的合成及提纯方法都很复杂 ,并且需要很长的反应时间 .本文采用一种新的…     

荧光聚合物研究进展*

本文总结了近年来荧光聚合物的研究进展,主要介绍了荧光聚合物的分类：按其溶解性能可分为非水溶性、水溶性和两亲荧光聚合物三大类;荧光聚合物的合成：荧光化合物为引发剂、荧光化合物为链转移剂、荧光功能单体聚合、荧光化合物与聚合物的化学键合、非荧光功能单体聚合等五种制备荧光聚合物的设计合成方法;荧光聚合物的应用：荧光聚合物在荧光化学传感器、荧光分子温度计、荧光造影、药物载体、荧光探针等方面的应用研究。     

可溶性聚苯并噻吩的电化学合成

聚噻吩及其衍生物具有良好的导电性 ,优越的电致变色及荧光特性 ,可望用于研制各种新型微电子器件[1,2 ] .因此 ,这类聚合物的合成与表征一直受到广泛关注[3] .噻吩类聚合物是一个庞大的家族 ,其中聚异苯并噻吩早就被合成出来[4 ,5] .三氟化硼乙醚溶液 (ＢＦＥＥ)是电聚合芳香族化合物 (如噻吩、苯等 )的一种优良电解质[6～ 10 ] .在这一介质中 ,单体的氧化聚合电位很低 ,得到的导电高分子膜具有优良的机械力学性能 .本文将报道苯并噻吩在纯ＢＦＥＥ或ＢＦＥＥ与浓硫酸形成的混合电解质中的电化学聚合反应 .用这一方法合成得到了能发出蓝色…     

以聚苯乙烯为把的聚四氢呋喃(PTHF)梳型聚合物的制备

高分子的自组装已成为当今高分子科学的热门研究课题之一[1] .开展该研究工作 ,首先要获得特定结构的聚合物 .我们设计合成如图 1所示的梳型聚合物 ,调节制备Ａ ,Ｂ ,Ｃ三链段所用的单体和它们的聚合度等参数 ,并进一步进行自组装研究 .若Ａ段是结晶聚合物 ,且熔融温度低于Ｃ段的玻璃化转变温度 ,则在定型储能材料等方面具有应用前景 .合成梳型嵌段聚合物有三个方法 ,即发散 (Ｇｒａｆｔｆｒｏｍ) ,收敛 (Ｇｒａｆｔｔｏ)和大分子方法 .采用大分子技术 ,每个梳型链长及支化密度可控 ,一直是人们青睐的方法[2 ] .一般采用与普通烯类单体共聚…     

含(R)或(S)-1,1''''-联萘和噁二唑单元的手性高分子合成与性质研究

在Pd(PPh3)4催化下, 将单体(S)-6,6'-二溴-2,2'-二正丁氧基-1,1'-联萘[(S)-M-1]和(R)-6,6'-二溴-2,2'-二正丁氧基-1,1'-联萘[(R)-M-1]分别与2,5-二(4-三正丁基锡基苯)-1,3,4-噁二唑(M-2)通过Stille交叉耦合反应合成了手性高分子P-1与P-2, 并用 1H NMR、 13C NMR、 FTIR、 UV、热分析、荧光光谱、 GPC和CD等分析方法进行了表征. 手性高分子P-1和P-2都能发射较强的蓝色荧光; 在高分子侧链上引入丁氧基后使得手性高分子的溶解性能增强, 并具有良好的成膜性能; 在高分子主链引入亲电子的噁二唑生色团能使其特别适合于作为空穴电子传输层, 对氧和热特别稳定, 是一类潜在的光电高分子材料.     

含(R)或(S)-1,1′-联萘和噁二唑单元的手性高分子合成与性质研究

在Pd(PPh3)4催化下,将单体(S)-6,6′-二溴-2,2′-二正丁氧基-1,1′-联萘[(S)-M-1]和(R)-6,6′-二溴-2,2′-二正丁氧基-1,1′-联萘[(R)-M-1]分别与2,5-二(4-三正丁基锡基苯)-1,3,4-噁二唑(M-2)通过Stille交叉耦合反应合成了手性高分子P-1与P-2,并用1HNMR、13CNMR、FTIR、UV、热分析、荧光光谱、GPC和CD等分析方法进行了表征.手性高分子P-1和P-2都能发射较强的蓝色荧光;在高分子侧链上引入丁氧基后使得手性高分子的溶解性能增强,并具有良好的成膜性能;在高分子主链引入亲电子的噁二唑生色团能使其特别适合于作为空穴电子传输层,对氧和热特别稳定,是一类潜在的光电高分子材料.     

一缩二乙二醇二甲基丙烯酸酯接枝真丝的结构

通过电子扫描电镜 (SEM)、红外光谱 (IR)、双折射、X 射线衍射及氨基酸分析等手段 ,研究了真丝用一缩二乙二醇二甲基丙烯酸酯 (P 2 )接枝后其结构与接枝率之间的关系 .氨基酸分析结果表明P 2接枝主要在真丝大分子中酪氨酸、丝氨酸、组氨酸和精氨酸的NH2 、OH和—NH—活性基团上 .通过X 射线衍射分析 ,P 2接枝并不直接影响结晶区 ,但引起分子取向的下降 ,接枝后真丝双折射下降说明接枝后因大分子取向度下降 ,接枝真丝的红外光谱显示出真丝具有 β折迭结构和P 2高聚物的结构特征峰 ,从而说明P 2接枝在纤维的无定型区内部进行 .当接枝率大于 35 %时 ,纤维的表面覆盖了一层高聚物 (P 2 ) ,并且纤维的横截面表现出明显的分纤现象 ,接枝真丝的红外光谱表明了纤维与P 2重叠吸收峰 ,说明了P 2在丝纤维内部接枝聚合 .     

Solvent- and environment-dependent fluorescence of modified nucleobases

Fluorescent nucleosides with modified nucleobases are useful tools for detecting nucleic acids and probing their structures and functions. Nucleobases are suitable for modification because 1) intrinsically light-absorbing nucleobases can be converted to fluorescent chromophores by simple chemical modification, 2) attaching substituents to nucleobases at appropriately selected positions does not inhibit base pairing or duplex formation, and 3) duplex formation and protein interactions affect the environment of nucleobases, causing changes in their fluorescence intensities and/or wavelengths. This review summarizes recent fluorescent nucleosides and their photophysical properties, such as absorption wavelength, emission wavelength, and fluorescence quantum yield together with their solvent dependency.     

基于咪唑的荧光传感器对磷酸二氢根离子的高选择性识别

设计并合成了基于咪唑基团的高选择性的荧光传感器, 分别利用荧光和紫外-可见光谱研究了其对阴离子的识别. 结果显示, 该类荧光传感器只在H₂PO₄^-离子存在下发生显著的荧光猝灭现象, 并且产生一个新的荧光发射峰, 因此可用于乙腈溶液中H₂PO₄^-的快速有效检测.     

A highly sensitive assay for spectrofluorimetric determination of reduced glutathione using organic nano-probes

In this study, the new nanometer-sized fluorescent particles (1-pyrenemethylamine nanoparticles) have been prepared by reprecipitation method under ultrasonic radiation. These nanoparticles have the potential to overcome problems encountered by organic small molecules by combining the advantages of high photobleaching threshold, high quantum yield, long fluorescence lifetime, good chemical stability, and wide excitation spectral properties. These nanoparticles will be able to be directly used as fluorescent nanoparticles probe without modification. A new fluorimetric method for the determination of reduced glutathione (GSH) has been developed with these nanoparticles. Under optimal conditions, the organic nanoparticles reacted with GSH and o-phthalaldehyde (OPA) to give a highly fluorescent derivative in Na2CO3-HCl buffer (pH=9.0). The fluorescence excitation and emission wavelengths of fluorescent derivative were located at 345 and 400 nm, respectively. The relative fluorescence intensity (RF) was linear in the range of the GSH concentration from 8.0x10(-7) to 1.1x10(-4)moll(-1). Limit of detection of 7.1x10(-8)moll(-1) was achieved for the reduced glutathione. The method was validated and applied to the analysis of three synthetic samples containing reduced glutathione.     

Nido-carborane encapsulated by BODIPY zwitterionic polymers: Synthesis,photophysical properties and cell imaging

Carborane encapsulation was visualized by using fluoroboropyrrole (BODIPY) zwitterionic polymer as fluorescence marker. Firstly, a water-soluble fluorescent probe carrier was prepared by combining the BODIPY derivatives with poly (carboxybetaine methacrylate) (p-CBMA). Two oil-in-water carborane polymers were self-assembled in organic solvents by means of dual ion hydrogen bonding. The ultraviolet and fluorescence spectra were measured with different organic solvents, and the spectra ranged from 531 to 555 nm. The dynamic self-assembly effect was tested by TEM, and the internal microscopic phenomena of the water-soluble polymer were further observed. It was confirmed that two kinds of BODIPY zwitterionic polymers were firmly encase the fat-soluble carborane, forming an oval shape. Carboranes are water-soluble, can achieve biocompatible expression, and can visualize the degree of aggregation in the targeted cells through its own fluorescence effect. Subsequent imaging of the cells showed that both polymers entered the targeted cells.     

Fluorescence derivatisation of amino acids in short and long-wavelengths

3-(Naphthalen-1-ylamino)propanoic acid was coupled to the amino group of the main and lateral chains of various amino acids in order to evaluate its applicability as a fluorescent derivatising reagent. The resulting amino acid derivatives are strongly fluorescent with a maximum emission of about 415 nm. Condensation of these derivatives with 5-ethylamino-4-methyl-2-nitrosophenol hydrochloride resulted in the corresponding blue benzo[a]phenoxazinium conjugates, also revealing strong fluorescence in ethanol and water at physiological pH and good quantum yields, but with emission wavelengths between 644 and 657 nm, which was preferable in biological assays.     

Polyazapodands Derived from Biphenyl. Study of their Behaviour as Conformationally Regulated Fluorescent Sensors

Eight new polyazapodands containing a 4,4′-substituted biphenyl moiety have been synthesised. Four (7, 8, 9 and 11) are functionalised on positions 4 and 4′ with a nitro group and four (1, 2, 3 and 10) with a dimethylamino substituent. Comparison of the emission behaviour of 1, 2, 3 with that of the reference compounds 10 and tetramthylbenzidine, clearly suggests that a modification in the dihedral angle between the biphenyl rings is an important factor in determining the fluorescent response of the molecule. The fluorescence is pH dependent, due to the formation of intramolecular hydrogen bonds between protonated aliphatic nitrogens and a carbonyl oxygen, which influences the aforementioned dihedral angle. A crystal structure resolved by X-ray diffraction of 7·2HCl has been determined, and confirms the dependence of the angle and the rigidity on the hydrogen bonding. The complexation properties of these ligands have been studied with Zn²⁺, Cd²⁺, Ni²⁺, Cu²⁺ and Pb²⁺, which show that the number of amino groups within the pendants has a strong influence on the nature of the complexation and the fluorescent response of each ligand.     

Fluorescent Supramolecular Polymersomes Based on Pillararene/Paraquat Molecular Recognition for pH-controlled Drug Release

Researchers have put significant efforts on developing versatile fluorescent polymeric systems due to their promising biological/biomedical labelling, tracking, monitoring, imaging, and diagnostic applications. However, complicated organic/polymeric synthesis or post-modification of these functionalized platforms is still a big obstacle for their further application and thereby provides clear motivation for exploring alternative strategies for the design and fabrication of easily available fluorescent systems. The marriage of supramolecular polymers and fluorescent imaging can provide a facile and dynamic manner instead of tedious and time-consuming synthesis due to the dynamic and reversible nature of noncovalent interactions. Herein, based on water-soluble pillararene/paraquat molecular recognition, we successfully prepare two amphiphilic polypseudorotaxanes which can self-assemble into supramolecular polymersomes in water. These polymersomes can be reversibly destroyed and reformed by tuning the solution p H. Attributed to the aggregation-induced emission of tetraphenylethylene groups,intense fluorescence can be introduced into the obtained supramolecular polymersomes. Furthermore, p H-triggered release of an encapsulated water-insoluble drug(doxorubicin) from the self-assembled fluorescent supramolecular polymersomes is also investigated.     

Synthesis of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene-silica core-shell particles with a self-templating method and their fluorescent properties

Sub-micrometer particles with poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) cores coated by silica-based shells were prepared with a self-templating method and their fluorescent properties were investigated in this paper. The characteristic of this method was that all reactions could be finished in one-pot, which exempted from removing the template and reduced reaction steps compared to the conventional process. Emission wavelength of the resultant core-shell particles can readily be tuned through chemical modification of MEH-PPV, which was carried out via regulating the conjugation length of the polymer. In addition, the size of MEH-PPV/SiO₂ core-shell particles could be controlled by altering reaction conditions. The obtained particles had clear core-shell structure and may be used as biolabeling materials. The morphologies, particle size distribution and fluorescent properties of MEH-PPV/SiO₂ particles were characterized by transmission electron microscopy (TEM), particle size analyzer and fluorescence emission spectra, respectively.