自由基聚合制备聚集诱导发光聚合物

首先制备了基于四苯基乙烯的聚集诱导发光(AIE)单体1-(4-丁烯氧基苯基)-1,2,2-三苯基乙烯(TPEBE)。然后,通过自由基溶液聚合法,将少量TPE-BE与丙烯酰胺和丙烯酸共聚制备了亲水性聚合物P1,与苯乙烯共聚制备了疏水性聚合物P2。利用红外光谱表征了P1和P2的结构,通过荧光光谱研究了P1和P2的发光性能,并探讨了聚合物亲疏水性对其发光行为的影响;采用扫描电子显微镜(SEM)观察了P2在四氢呋喃(THF)/H_2O混合溶剂中的微观形态。结果表明:P1在水中发出蓝光,随着THF的加入,荧光逐渐减弱,然而,P2在THF及THF/H_2O混合物中都不发光,表明聚合物的亲疏水性能够影响其发光行为。然而,P1和P2的固态粉末都发出较强的荧光,说明P1和P2具有聚集诱导发光性能。P2在水质量含量超过30%的THF/H_2O混合溶剂中能够形成微球。这表明通过调整共聚单体的种类,有望制备出结构和功能多样的AIE聚合物。     

二元溶剂体系对含仲胺基团苝酰亚胺衍生物自组装与光电性能的影响

设计了一种含仲胺基团的苝酰亚胺衍生物N,N-二(2-乙基乙二胺基)-1,6,7,12-四(4-叔丁基苯氧基)-3,4,9,10-苝酰亚胺(B-PDI-1),并采用紫外吸收光谱与荧光光谱研究了B-PDI-1在四氢呋喃(THF)/H2O混合溶剂中的光物理性质;通过扫描电镜(SEM)与X射线粉末衍射(XRD)表征B-PDI-1在THF/H2 O中所形成的聚集体形态结构;利用循环伏安法(CV)与Guassion模拟运算研究了其变色机理;使用电化学工作站测定了聚集体的J-V曲线与瞬态光响应,并评估了它的光伏性能.结果表明,B-PDI-1在THF/H2 O二元溶剂体系自组装过程中由红色变为蓝色,其紫外吸收光谱则出现了红移现象,在THF含量fTHF=10％时达到了最大值35.4 nm,随着THF/H2 O二元溶剂体系中THF含量减少,荧光强度将会逐渐降低,但始终存在着微弱的荧光,意味着B-PDI-1具有J型聚集的特征;B-PDI-1在不同THF/H2 O比例的混合溶液中都能形成具有明确形貌的聚集体,在不同THF含量的溶液中分别获得了螺旋带状、长斜四边形、棒状、类球形以及长直纳米带等纳米结构;随着该组装体系中THF含量发生变化,分子堆积方式也将改变,分子间的微扰作用集中体现在HOMO能级的提高,由于不同聚集体能带的差异导致了颜色的变化,且在fTHF=10％时B-PDI-1的光波转化效率达到最大值(0.43％).     

具有聚集诱导发光特性含萘单元共轭聚合物的合成

首先氯化亚砜和2,6-萘二甲酸酰氯化反应合成2,6-萘二甲酰氯(M1),然后M1和叔丁基苯傅-克酰基化反应合成2,6-二(4-叔丁基苯甲酰基)萘(M2),进而与1,2-乙二硫醇合成2,6-双(2-(4-(叔丁基)苯基)-1,3-二巯基-2-基)萘(M3),最后以六羰基钨为催化剂,分子间脱硫反应制备含萘单元共轭聚合物PNTB。利用傅里叶变换红外光谱仪、核磁共振波谱仪、凝胶渗透色谱仪、紫外-可见分光光度计和荧光分光光度计对M2、M3和PNTB的化学结构、相对分子质量和光学性质进行测试与表征。结果表明,随四氢呋喃/水(THF/H_2O)混合溶剂中水分数不断增加,PNTB的荧光强度呈递增的趋势,表明PNTB具有聚集诱导发光特性。PNTB在溶液状态(THF为溶剂)和聚集状态(THF/H_2O,体积比10/90)的荧光量子产率分别为1.83%和12.74%,说明PNTB容易发生聚集,聚集诱导发光效果良好。     

传统生色团的改造:从聚集导致荧光猝灭到聚集诱导发光

传统的荧光生色团聚集后导致荧光淬灭,即聚集导致荧光猝灭(ACQ)现象。ACQ现象的存在严重限制了荧光生色团的应用。与ACQ相反,有一类发光材料在良溶剂中荧光微弱甚至没有荧光,然而,在聚集状态下荧光显著增强,这种现象被命名为聚集诱导发光(AIE)现象。AIE材料的迅速发展为ACQ材料带来了契机,众多研究者利用AIE体系改造ACQ生色团使传统ACQ材料具有新的性能和应用价值。介绍了近年来有关利用AIE体系改造ACQ生色团的研究进展。侧重总结了利用噻咯体系、取代乙烯体系(主要包括四苯基乙烯、三苯基乙烯及三苯基乙烯基咔唑)和三苯基丙烯腈体系对三苯胺类、稠环类和并苯酰亚胺类ACQ生色团的改造,及得到的新材料的性能和应用,并对该领域的发展前景进行了展望。     

咔唑-查尔酮衍生物微纳米粒子制备与聚集体荧光增强效应研究

利用简单合成法首次合成了3种新的咔唑-吡啶-查尔酮衍生物,结合SEM谱图、紫外吸收光谱和荧光光谱分析发现,样品中吡啶-查尔酮基团增多有利于聚集体形成且颗粒尺寸变小,可达到纳米级。3种样品均呈J-型堆积聚集。稳态/瞬态荧光测试结果表明,由于溶液态到聚集态,3个样品的荧光量子产率提高,辐射衰减寿命增大,导致化合物聚集体的辐射衰减速率增大,非辐射衰减速率降低。     

氰基苯乙烯基聚集诱导发光材料在光和pH调控下的多颜色和荧光转换（英文）

本文精心设计了一种具有聚集诱导发光增强特性的氰基苯乙烯基荧光团(Z-BDPA),由于其具有各种光化学反应和可逆的pH响应而呈现出多种可调节的颜色和荧光.在420 nm光照射下, Z-BDPA在四氢呋喃(THF)中发生Z→E异构化,其绿色荧光增强,该过程在365 nm光照射下可恢复;由于发生光二聚化过程, Z-BDPA在水含量(fw)为90%的THF/H₂O混合体系中的黄色荧光变为更强的黄绿色荧光.在酸性条件下,具有黄色荧光的Z-BDPA粉末通过质子化过程变为具有蓝色荧光的AIE荧光团Z-p-BDPA,该过程可通过在碱性条件下的去质子化作用恢复.在365 nm光照射下, Z-p-BDPA的蓝色荧光由于光异构化过程和随后的光环脱氢反应而蓝移且增强.基于其对于光化学反应和pH响应而呈现出的可调控的颜色和荧光, Z-BDPA可成功应用于光图案化和防伪.     

新型三苯胺树枝分子的合成及荧光发射性质

采用Wittig-Horner反应合成了一种新型三苯胺树枝分子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),并测定了化合物TPAB-OXA在不同溶剂中的紫外吸收光谱、荧光发射光谱及量子产率、荧光寿命.在二氯甲烷中...     

蓝色荧光喷墨油墨的荧光光谱与荧光量子产率

测试了荧光喷墨油墨的激发光谱与荧光光谱,用相对测量法测定了荧光喷墨油墨在不同激发波长下的荧光量子产率,探讨了溶剂种类以及树脂含量对荧光喷墨油墨量子产率的影响。结果表明,溶剂极性和树脂含量对荧光喷墨油墨的荧光量子产率均有较大影响,在二丙二醇甲醚中,荧光量子产率最大为O．96;与树脂质量分数为8％时相比,树脂质量分数为10％时的荧光量子产率较大。     

明胶的改进和提纯

本发明叙述适于各种照相乳剂的惰性明胶制备方法。本方法为将非饱和活性化合物加入明胶中硫化物的氢硫基团中,经作用后生成与照相上性能无害惰性的芳基或烷基硫化物。用于本发明中与氢硫基团起化合反应的非饱和化合物分类举例如下: 1.正芳基或正烷基马来酰亚胺,其中劳基类为苯基、甲苯基或萘基,烷基为甲烷、乙烷、丙烷、丁烷和癸烷基等。 2.属于一般化学式的乙烯酯类: H_2C=CH—G 其中R为烷基如甲烷、乙烷、丙烷、丁     

含噁二唑类与咔唑类共聚物的合成与表征

由2-苯基-5-〔甲基丙烯酰胺基取代苯基〕-1,3,4-噁二唑(OXD)与甲基丙烯酸乙基咔唑酯(CzE-MA)两种单体合成了含噁二唑和咔唑基团的无规共聚物。通过红外、核磁、紫外、荧光、热重、差示扫描量热,凝胶渗透色谱对聚合物进行了表征。测试结果表明共聚物有很好的溶解性,均可溶于常用的有机溶剂,如THF,CHCl2,CHCl3等,其分子量在16950～22500之间。有良好的热稳定性和很高的玻璃化转变温度(Tg=190～222℃),最大吸收波长在220～340nm之间,具有良好的荧光性,其荧光发射波长均在372～451nm范围内,是一类蓝紫色荧光聚合物。共聚物随着CzEMA组分的减少和OXD组分的增加,发射波长蓝移,其中以P(OXD8-CzEMA2)的荧光性最好,荧光量子产率高达0.70。     

Domain and network aggregation of CdTe quantum rods within Langmuir-Blodgett monolayers

Control over the organization of quantum rods was demonstrated by changing the surface area at the air-liquid interface by means of the Langmuir-Blodgett (LB) technique. The LB isotherm of CdTe quantum rods capped with a mixture of alkylphosphines shows a transition point in the liquid-solid state, which is caused by the inter-rod reorganization. As we observed, at low surface pressure the quantum rods are assembled into round-shaped aggregates composed of a monolayer of nanorods packed in limited-size clusters with random orientation. The increase of the surface pressure leads to the rearrangement of these aggregates into elongated bundles composed of uniformly oriented nanorod clusters. Further compression results in denser packing of nanorods aggregates and in the transformation of monolayered domains into a continuous network of locally ordered quantum rods.     

Efficient Aggregation‐Induced Emission Manipulated by Polymer Host Materials

Linear copolymer hosts bearing a number of pillar[5]arene dangling side chains are synthesized for the facile construction of highly emissive supramolecular polymer networks (SPNs) upon noncovalently cross‐linking with a series of tetraphenyethylene (TPE)‐based tetratopic guests terminated with different functional groups through supramolecular host–guest interactions. An extremely high fluorescence quantum yield (98.22%) of the SPNs materials is obtained in tetrahydrofuran (THF) by fine‐tuning the parameters, and meanwhile supramolecular light‐harvesting systems based on spherical supramolecular nanoparticles are constructed by interweaving 9,10‐distyrylanthracene (DSA) and TPE‐based guest molecules of aggregation‐induced emission (AIE) with the copolymer hosts in the mixed solvent of THF/H₂O. The present study not only illustrates the restriction of the intramolecular rotations (RIR)‐ruled emission enhancement mechanism regulated particularly by macrocyclic arene‐containing copolymer hosts, but also suggests a new self‐assembly approach to construct high‐performance light‐harvesting materials.     

Bright Aggregation‐Induced‐Emission Dots for Targeted Synergetic NIR‐II Fluorescence and NIR‐I Photoacoustic Imaging of Orthotopic Brain Tumors

Precise diagnostics are of significant importance to the optimal treatment outcomes of patients bearing brain tumors. NIR‐II fluorescence imaging holds great promise for brain‐tumor diagnostics with deep penetration and high sensitivity. This requires the development of organic NIR‐II fluorescent agents with high quantum yield (QY), which is difficult to achieve. Herein, the design and synthesis of a new NIR‐II fluorescent molecule with aggregation‐induced‐emission (AIE) characteristics is reported for orthotopic brain‐tumor imaging. Encapsulation of the molecule in a polymer matrix yields AIE dots showing a very high QY of 6.2% with a large absorptivity of 10.2 L g^?1 cm^?1 at 740 nm and an emission maximum near 1000 nm. Further decoration of the AIE dots with c‐RGD yields targeted AIE dots, which afford specific and selective tumor uptake, with a high signal/background ratio of 4.4 and resolution up to 38 µm. The large NIR absorptivity of the AIE dots facilitates NIR‐I photoacoustic imaging with intrinsically deeper penetration than NIR‐II fluorescence imaging and, more importantly, precise tumor‐depth detection through intact scalp and skull. This research demonstrates the promise of NIR‐II AIE molecules and their dots in dual NIR‐II fluorescence and NIR‐I photoacoustic imaging for precise brain cancer diagnostics.     

Facile Synthesis of Efficient Luminogens with AIE Features for Three-Photon Fluorescence Imaging of the Brain through the Intact Skull

Visualization of the brain in its native environment is important for understanding common brain diseases. Herein, bright luminogens with remarkable aggregation-induced emission (AIE) characteristics and high quantum yields of up to 42.6% in the solid state are synthesized through facile reaction routes. The synthesized molecule, namely BTF, shows ultrabright far-red/near-infrared emission and can be fabricated into AIE dots by a simple nanoprecipitation procedure. Due to their high brightness, large Stokes shift, good biocompatibility, satisfactory photostability, and large three-photon absorption cross section, the AIE dots can be utilized as efficient fluorescent nanoprobes for in vivo brain vascular imaging through the intact skull by a three-photon fluorescence microscopy imaging technique. This is the first example of using AIE dots for the visualization of the cerebral stroke process through the intact skull of a mouse with high penetration depth and good image contrast. Such good results are anticipated to open up a new venue in the development of efficient emitters with strong nonlinear optical effects for noninvasive bioimaging of living brain.     

具有自组装纳米结构的AIE光敏剂用于增强光动力治疗（英文）

基于具有聚集诱导发光(AIE)性质的2,3-双(4’-(二苯基)-[1,1’-联苯]-4-基]富甲腈(BDBF)分子,制备了三种纳米结构并用于图像引导光动力学治疗(PDT).普兰尼克F127可包封BDBF形成常见的球形纳米粒子(F127@BDBF NPs),该纳米粒子可发射红色荧光,荧光量子效率(FQY)为9.8%.此外, BDBF也可在水中自组装成纳米棒(BDBF NRs).与F127@BDBF NPs相比, BDBF NRs呈现出较强的橙色荧光,具有较高的荧光量子产率(23.3%),以及基本相同的单线态氧(1O2)产生能力.利用F127对BDBF NRs进行进一步修饰可得到BDBF@F127 NRs,该纳米粒子仍然保持了棒状形貌和较好的1O2产生能力.同时,与溶解态的BDBF相比,三种纳米结构的单线态氧产生效率增强.这些纳米结构在水溶液和生理条件下具有良好的稳定性.细胞的光毒性实验表明,三种纳米结构均能有效抑制肿瘤细胞增殖.因此,通过简单的自组装方法制备高荧光量子效率和较强单线态氧产生能力的纳米结构可作为一种有效的途径来增强光动力.     

基于谷氨酸衍生物和脂肪酸双元有机凝胶的有序纳米结构和组装模式研究

设计研究了具有不同烷基链长度的脂肪酸与谷氨酸衍生物在多种有机溶剂中的双元凝胶行为,在20种溶剂中的凝胶性能测试结果表明是新型双元有机胶凝剂,实验结果表明,烷基链的长度在调控多种有机溶剂中的胶凝剂性能方面起着关键作用,分子骨架中较长的烷基链有助于有机溶剂的胶凝;形貌研究揭示这些凝胶分子随着溶剂的改变自组装形成不同的聚集体,例如片状、棒状、纤维状等;光谱考察表明,取决于分子骨架中酰胺基团和烷基取代链,形成不同的氢键和疏水作用力。此外,使用的溶剂对于这些双元凝胶剂的组装模式和堆积单元也有明显的作用。该工作为设计新型双元有机胶凝剂和软材料提供了新的思路。     

Aggregation‐Induced Dual‐Phosphorescence from Organic Molecules for Nondoped Light‐Emitting Diodes

Aggregation‐induced emission (AIE) is a beneficial strategy for generating highly effective solid‐state molecular luminescence without suffering losses in quantum yield. However, the majority of reported AIE‐active molecules exhibit only strong fluorescence, which is not ideal for electrical excitation in organic light‐emitting diodes (OLEDs). By introducing various substituent groups onto the biscarbazole compound, a series of molecular materials with aggregation‐induced phosphorescence (AIP) is designed, which exhibits two distinctly different phosphorescence bands and an absolute solid‐state room‐temperature phosphorescence quantum yield up to 64%. Taking advantage of the AIE feature, the AIP molecules are fabricated into OLEDs as a homogeneous light‐emitting layer, which allows for relatively small efficiency roll‐off and shows an external electroluminescence quantum yield of up to 5.8%, more than the theoretical limit for purely fluorescent OLED devices. The design showcases a promising strategy for the production of cost‐effective and highly efficient OLED technology.     

Effect of Surface Coating on the Photocatalytic Function of Hybrid CdS–Au Nanorods

Hybrid semiconductor–metal nanoparticles are interesting materials for use as photocatalysts due to their tunable properties and chemical processibility. Their function in the evolution of hydrogen in photocatalytic water splitting is the subject of intense current investigation. Here, the effects of the surface coatings on the photocatalytic function are studied, with Au‐tipped CdS nanorods as a model hybrid nanoparticle system. Kinetic measurements of the hydrogen evolution rate following photocatalytic water reduction are performed on similar nanoparticles but with different surface coatings, including various types of thiolated alkyl ligands and different polymer coatings. The apparent hydrogen evolution quantum yields are found to strongly depend on the surface coating. The lowest yields are observed for thiolated alkyl ligands. Intermediate values are obtained with L‐glutathione and poly(styrene‐co‐maleic anhydride) polymer coatings. The highest efficiency is obtained for polyethylenimine (PEI) polymer coating. These pronounced differences in the photocatalytic efficiencies are correlated with ultrafast transient absorption spectroscopy measurements, which show a faster bleach recovery for the PEI‐coated hybrid nanoparticles, consistent with faster and more efficient charge separation. These differences are primarily attributed to the effects of surface passivation by the different coatings affecting the surface trapping of charge carriers that compete with effective charge separation required for the photocatalysis. Further support of this assignment is provided from steady‐state emission and time‐resolved spectral measurements, performed on related strongly fluorescing CdSe/CdS nanorods. The control and understanding of the effect of the surface coating of the hybrid nanosystems on the photocatalytic processes is of importance for the potential application of hybrid nanoparticles as photocatalysts.     

Cyclodextrin Insulation Prevents Static Quenching of Conjugated Polymer Fluorescence at the Single Molecule Level

Conjugated polymers (CPs) are promising materials for fluorescence imaging application. However, a significant problem in this field is the unexplained abnormally low fluorescence brightness (or number of fluorescence photons detected per one excitation photon) exhibited by most of CP single chains in solid polymer hosts. Here it is shown that this detrimental effect can be fully avoided for short chains of polyfluorene‐bis‐vinylphenylene (PFBV) embedded in a host polymer matrix of PMMA, if the conjugated backbone is insulated by cyclodextrin rings to form a polyrotaxane (PFBV‐Rtx). Fluorescence kinetics and quantum yields are measured for the polymers in liquid solutions, pristine films, and solid PMMA blends. The fluorescence brightness of PFBV‐Rtx single chains dispersed in a solid PMMA is very close to that expected for a chain with 100% fluorescence quantum yield, while the unprotected PFBV chains of the same length possess 4 times lower brightness. Despite this, the fluorescence decay kinetics are the same for both polymers, suggesting the presence of static or ultrafast fluorescence quenching in the unprotected polymer. About 80% of an unprotected PFBV chain is estimated to be completely quenched. The hypothesis is that the cyclodextrin rings prevent the quenching by working as ‘bumpers’ reducing the mechanical forces applied by the host polymer to the conjugated backbone and help retaining its conformational freedom. While providing a recipe for making CP fluorescence bright at the single‐molecule level, these results identify a lack of fundamental understanding in the community of the influence of the environment on excited states in conjugated materials.