主客体掺杂的偶氮类聚合物薄膜的制备和全光极化特性

采用旋转甩膜法制备了主客体掺杂型的偶氮类聚合物薄膜．构成薄膜的光学活性生色团包括分散红1、分散橙25、分散黄7、分散红54,基体为聚甲基丙烯酸甲酯(PMMA)或聚碳酸酯(PC)。利用扫描电镜(SEM)、X射线衍射(XRD)、差示扫描量热计(DSC)、红外光谱法(IR)、紫外-可见吸收谱仪和显微硬度仪等对样品的表面、染料的结晶性、玻璃化转变温度、掺杂聚合物的结构、薄膜的吸收谱以及硬度进行了分析。并系统研究了工艺条件对偶氮类聚合物薄膜的全光极化特性的影响。实验表明,分散染料浓度越大光极化产生的二阶非线性效应越强,这与单位面积内聚合物薄膜中含有较高浓度的分散红有关。通过普通热处理的聚合物薄膜样品,在避光保存的条件下,产生的全光极化效果最明显。总之,偶氮类聚合物薄膜全光极化下的二次谐波强度与其制备过程中的参数有密切的关系。     

Mesoscopic Supramolecular Assembly of Stereolithographically Printed Microgels

Microgels that assemble upon issuing of a trigger open up miscellaneous applications in soft robotics, drug delivery, and life-like materials, due to their unique physical and chemical properties. In this work, a novel hydrogel photoresist system is formulated, consisting of 2-hydroxyethyl acrylate, ethylene glycol diacrylate, and phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, as well as redox-sensitive supramolecular host-guest association motifs. Complex and multi-compartmented geometries with precisely located recognition motifs are printed in high resolution, resulting in multifunctional structured microgel building blocks for mesoscopic self-assembly. An enzymatic feedback system is employed to dissipatively assemble and disassemble the redox-active microgel building blocks in a temporally and spatially controlled pathway. The self-assembling photoresist system is characterized in terms of the lower critical solution temperature, swelling behavior, and printability. The present work provides new perspectives for the design of tailor-made mesoscopic microgels with customizable functionality and high applicability for various technological applications.     

Bambusuril Anion Receptors

Bambusurils are macrocyclic compounds whose synthesis was first reported in 2010. Since then bambusurils have been investigated mainly because of its six-membered homologues’ outstanding binding affinities towards inorganic anions in both organic solvents and water. Here we summarize the most important aspects of bambusuril chemistry. Basic characteristics of bambusurils are presented, followed by details of their synthesis, and a discussion of their supramolecular properties, with an emphasis on binding in water. Potential applications of bambusurils are highlighted at the end of the review.     

Dual Stimuli-Responsive Cross-Linked AIE Supramolecular Polymer Constructed through Hierarchical Self-Assembly

Herein, we report the successful construction of a new family of dual stimuli-responsive AIE cross-linked supramolecular polymer through the strategy of hierarchical self-assembly. A novel dipyridyl donor building block G1 containing tetraphenylethylene (TPE) moiety was designed and synthesized. Notably, two nitrile units were attached onto G1 , which were employed as the guest for the further host-guest interaction with pillar[n]arene derivatives. The rhomboidal metallacycle G2 with four nitrile units was firstly constructed through coordination-driven self-assembly. Subsequently, the cross-linked supramolecular polymers H₂⊃G2 were then generated through host-guest interactions. It should be noted that the obtained supramolecular polymer displayed interesting AIE properties due to the restriction of TPE intramolecular motions within the polymeric network. More importantly, by taking advantages of dynamic nature of both coordination bonds and host-guest interactions, the resultant supramolecular polymer displayed dual stimuli-responsive fluorescent transitions under different stimuli such as the competitive guest and halide anion.     

Inclusion Complexes of Hymexazol with Three Different Cucurbit[n]uril: Preparation,and Physicochemical and Antifungal Characterization

Host-guest inclusion complexes of hymexazol with three different cucurbit[n]uril, cucurbit[7]uril (Q[7]), hemimethyl-substituted cucurbit[6]uril (HHMeQ[6]), and twisted cucurbit[14]uril (tQ[14]) have been investigated by means of ¹H NMR spectroscopy, quadrupole-time of flight mass spectrometry (Q-TOF), and isothermal titration calorimetry (ITC). ¹H NMR experimental results revealed that hymexazol resides within the respective cavities of the selected Q[n], and mass spectrometric experimental results revealed that it interacts with these three Q[n] through the formation of 1 : 1 inclusion complexes. ITC experimental results indicated moderate binding constants. In vitro assays showed that the complexation of hymexazol by the Q[n] increased its inhibitory effect on the mycelia growth of Botrytis cinerea Pers.     

High efficient and high color pure blue light emitting materials: New asymmetrically highly twisted host and guest based on anthracene

New asymmetrically highly twisted anthracene derivatives serve as a matched host and guest material in high efficiency blue OLEDs. 2-(2-Methylnaphtathalene-1-yl)-9,10-di(naphthalene-2-yl)anthracene and N-(4-(10-naphthalene-2-yl)anthracene-9-yl)phenyl-N-phenylnaphthalene-2-amine were prepared as host material and as guest material, respectively. Multilayer organic electroluminecent devices constructed using these foregoing twisted anthracene derivatives as the emitting layer gave quantum efficiencies of 5% and exhibited a pure blue emission with CIE chromaticity coordinates x = 0.15, y = 0.14-0.18.     

NMR Studies on Li+, Na+ and K+ Complexes of Orthoester Cryptand o-Me2-1.1.1

Cryptands, a class of three-dimensional macrobicyclic hosts ideally suited for accommodating small guest ions, have played an important role in the early development of supramolecular chemistry. In contrast to related two-dimensional crown ethers, cryptands have so far only found limited applications, owing in large part to their relatively inefficient multistep synthesis. We have recently described a convenient one-pot, template synthesis of cryptands based on O,O,O-orthoesters acting as bridgeheads. Here we report variable-temperature, ¹H-1D EXSY and titration NMR studies on lithium, sodium, and potassium complexes of one such cryptand (o-Me₂-1.1.1). Our results indicate that lithium and sodium ions fit into the central cavity of the cryptand, resulting in a comparably high binding affinity and slow exchange with the bulk. The potassium ion binds instead in an exo fashion, resulting in relatively weak binding, associated with fast exchange kinetics. Collectively, these results indicate that orthoester cryptands such as o-Me₂-1.1.1 exhibit thermodynamic and kinetic properties in between those typically found for classical crown ethers and cryptands and that future efforts should be directed towards increasing the binding constants.     

Enhancement of photochromic hologram thermal stability

Significant enhancement of the thermal stability of the hologram recorded on photochromic materials had been achieved via covalent bonding of the photochromic dye to the polymer matrix as compared to the host-guest systems. One time partial reduction of the hologram’s initial diffraction efficiency due to thermal exposure was observed for both—polymers with attached dye as well as hostguest materials. Such one time reduction is interpreted to be due to the thermal relaxation of the polymer network induced with photochromic transition in the dye molecule. A gradual hologram erasure at elevated temperatures was observed for the host-guest system, which is assumed to be due to dye’s diffusion between highly lit and dark areas. For the photochromic materials with covalent boding of the dye to the polymer matrix the level of thermal stability is demonstrated such that at temperatures ca. 100C there was no detectable diffusion type degradation of the hologram after 6 hours of exposure to elevated temperature. Same heating of the hologram in photochromic host-guest polymer led to a full hologram erasure within 40 minutes. In both cases the one time initial DE reduction due to polymer matrix relaxation at elevated temperatures had comparable value of about 0.5 of hologram’s initial DE. The article is published in the original.     

对称四甲基六元瓜环与2-戊基苯并咪唑盐酸盐自组装包合物晶体结构

以对称四甲基六元瓜环(TMeQ[6])为主体,2-戊基苯并咪唑盐酸盐(PB)为客体,在水溶液中自组装形成主客体超分子化合物{PB@TMeQ[6]}.Cl.9(H2O),利用X-射线单晶衍射技术对化合物的晶体结构进行了表征。实验结果表明,主客体之间通过多种非共价键作用形成1∶1的主客体包合物,客体的芳环被瓜环包结于空腔内,烷基置于瓜环端口外侧,包合物结构单元之间与共用水分子通过氢键连接成一维超分子链。