分子识别作用下光催化降解偶氮染料酸性红B

以250 W金属卤化物灯(λ365 nm)为光源,二氧化钛为催化剂,研究了经分子识别作用后的酸性红B光催化降解行为,考察了影响光催化降解的条件因素。研究结果表明:对于20 mg/L的酸性红B,经β-环糊精分子识别后酸性红B的光催化降解效率可以提高24%;β-环糊精浓度、pH值和TiO2剂量对酸性红B的光催化降解速率有明显的影响。分子识别作用下酸性红B光催化降解的增强效应主要源于β-环糊精能有效促进酸性红B在TiO2表面的吸附。     

分子模拟技术在环糊精包结过程中的应用

环糊精具有疏水的空腔,可以选择性结合各种客体分子,形成稳定的包结物,在实验和理论研究中受到广泛的关注。本文总结了近年来分子模拟技术在环糊精包结过程中的应用,重点介绍半经验PM3方法、双层ONIOM方法及自然键轨道（NBO）分析方法。最后展望了分子模拟技术在环糊精领域的发展方向。     

基于AB型环糊精主客体相互作用的超分子聚合物的研究进展

对环糊精的羟基进行选择性衍生化,可以调节环糊精分子与客体分子的络合特性。文章综述了各类基于环糊精主客体相互作用的的组装单体,通过自组装可以形成不同拓扑结构的超分子聚合物组装体。     

竞争包结法研究β-环糊精对氨基酸的分子配位作用

以酚酞作为光谱探针,在25℃采用紫外-可见光谱滴定法测定了β-环糊精（β-CD）与三种氨基酸分子形成超分子配合物的稳定常数。结果表明,三种生物分子客体与β-环糊精主体之间的键合能力和选择性主要受疏水相互作用和空腔大小匹配程度的影响,几种非共价键弱相互作用力协同贡献于主-客体的包结配位过程。     

环糊精包合客体分子机理的研究

环糊精具有独特的疏水空腔结构，与一些物质包合后．能显著改变这些物质的理化性能。本文在环糊精包合染料的基础上，探讨了环糊精包合客体分子的机理。认为包合物形成主要取决于环糊精和客体分子结构及两者作用力的大小。客体分子或其中某些基团的大小与环糊精空腔大小相近的易于包合，两者之间的作用力大小影响包合物的稳定性，疏水力是包合过程主要推动力。     

1-萘酚-β-环糊精包合物结构的理论研究

环糊精及其衍生物因具有“内疏水,外亲水”结构,能选择性识剐小分子而备受关注。文章以2-萘酚-β-环糊精包合物为研究对象,采用PM3半经验方法探讨了1-萘酚分子在环糊精空腔中的位置以及旋转角度对包合体系能量的影喃,通过计算包合体系能量的变化趋势,优化了体系能量最低点时的包合物结构。结果表明,包合体系的能量随客体分子在环糊精空腔中旋转角度的变化而改变,环糊精空腔的非对称性对包合体系的能量有影响,在设计环糊精包合体系的计算模型时应考虑空腔的不对称性因素。     

甲氨基阿维菌素微胶囊的制备与研究

环糊精由七个吡喃葡萄糖单位通过α-1,4糖苷键连接所构成的环状分子,其可分为α-环糊精,γ环糊精和β-环糊精。环糊精的分子构型较为特殊,其内腔疏水,而外腔亲水,具有“内疏水,外亲水”的特殊分子结构,根据空腔大小,利用疏水作用力、氢键和范德华力等进行分子识别,环糊精能作为“宿主”包络不同“客体”化合物,形成结构特殊的包络物,因此具有较强的吸附能力,是-种性能优良的吸附材料。     

被修饰环糊精模版控制的trans-2-苯乙烯吡啶的分子内环化

环糊精（CDs）是由6,7或8吡喃葡萄糖与上下环绕的羟基组成的环状低聚糖,具有内疏水外亲水的结构特征。合成了一种酰化的γ-环糊精（CDs）,并将酰化的环糊精衍生物与trans-2-苯乙烯吡啶分子包合,比较了固态、液态及凝胶态中包合物的光反应结果,发现修饰的环糊精对其分子内光环化产物的生成具有选择性,其中固态产物的选择性最好,可以得到产率较高的苯并[f]喹啉。     

β-环糊精与罗丹明B及番红花红T包合作用的研究

合成了以β-环糊精为主体,罗丹明B及番红花红T为客体的包合物.用红外光谱、荧光光谱、共振瑞利散射光谱和差示扫描量热谱研究了β-环糊精与染料的包合机理.实验结果表明:β-环糊精与客体分子分别形成了1:1的包合物,客体分子进入β-环糊精分子的疏水性空腔内,当β-环糊精加入到一定浓度的客体溶液中时,罗丹明B体系的荧光强度和共振瑞利散射强度减弱,而番红花红T体系的荧光强度和共振瑞利散射强度增强.还通过荧光光谱法及共振瑞利散射光谱法分别测定了15、25和35 ℃ 3个不同温度时染料与β-环糊精包合体系的稳定常数.结果表明:包合物的形成主要取决于β-环糊精与客体分子的分子结构及两者作用力的大小,β-环糊精空腔大小与客体分子或其某些基团的大小越接近,越容易包合,包合物的稳定常数就越大.包合物的表观热力学常数显示,在上述包合体系反应的推动力是疏水作用力.     

β-环糊精促进双酚A光催化降解

研究了双酚A在β-环糊精存在的TiO2光催化体系中的光降解行为，结果表明：β-环糊精能促进双酚A的光催化降解，经过250W的金属卤化物灯（λ≥365nm）光照40min，β-环糊精能提高双酚A23％的光降解效率，同时研究了双酚A光降解的动力学规律及pH、β-环糊精浓度、双酚A初始浓度对双酚A的光降解的影响。光催化降解的促进作用源于β-环糊精促进双酚A在TiO2表面的吸附。     

Review of molecular imprinting polymer: basic characteristics and removal of phenolic contaminants based on the functionalized cyclodextrin monomer

Cyclodextrins (CDs) are formed of starch molecules that are linked together in a cyclic ring. They are composed of five or more (1, 4) connected D-glucopyranoside units. CDs have toroidal, hollow truncated cone structures with exterior hydrophilic edges and internal hydrophobic cavities. The numerous hydroxyl groups available in cyclodextrins are active sites capable of forming various sorts of connections. They can be cross-linked or derived to generate monomers able to form branching or linear networks. Furthermore, they can form inclusion complexes with a variety of guest molecules, including organic and inorganic molecules, thus changing their physicochemical properties, The modification of the imprinting method could produce molecularly imprinted polymers that are stable, dependable, long-lasting, selective, and cost-effective. As a result, molecularly imprinted polymers are becoming increasingly popular in chemical separation and analysis. As found in previous studies, the monomers of cyclodextrins used in molecular imprinting have a higher binding impact on target molecules. The purpose of this study is to highlight the application of imprinting technology utilizing cyclodextrins as a valuable functional monomer in the remediation of phenolic compounds by examining and assessing relevant works published in the literature. © 2022 Society of Chemical Industry (SCI).     

Block copolymer aggregates with photo-responsive switches: Towards a controllable supramolecular container

Herein, we present a concept of combining host-guest chemistry with block copolymer self-assembly to fabricate an inner cross-linking block copolymer aggregate with photo-responsive switches on the basis of the reversible interaction between azobenzene and β-cyclodextrin, which can serve as a controllable supramolecular container to load and release guest molecules reversibly. The inner cross-link makes the block copolymer aggregates exhibit good stability, and the aggregates can keep their spherical morphologies during photo-irradiation treatment. When the switches are in on-state, cyclodextrins can bind with hydrophobic pyrene molecules; and when the switches are in off-state, pyrene molecules will get away from the cyclodextrins. The photo-controllable switches embedded in the aggregates endow this new supramolecular container with the capability to load and release guest molecules reversibly without structure disruption. It is anticipated that this line of work may open an avenue for fabricating new polymeric containers which can be used for controllable molecular transfer and catalysis.     

Thermodynamics of the encapsulation by cyclodextrins

Molecular encapsulation on a molecular basis can be performed by cyclodextrins. The inclusion of organic molecules into the interior changes the properties of these molecules, which may be used for a broad variety of applications. The affinity of guest molecules for the cavities of various cyclodextrins depends on the stereochemistry and on the interaction forces of the molecules involved. Calculations of the thermodynamic parameters show that the reaction entropy is highly important for the inclusion reaction. Completely different reaction mechanisms are observed for various types of cyclodextrins as some of these reactions show enthalpy–entropy compensation. Others are supported by the reaction entropy or are even entropically controlled. Protonation and deprotonation reactions contribute significantly to the inclusion reaction, as first of all the solubility of the compounds in water is strongly influenced by the acidity of the solution, and, moreover, all tautomeric forms of the compounds show different affinities to various cyclodextrins. Copyright © 2006 Society of Chemical Industry     

Novel visible-light-responsive photo-catalysts based on palladium decorated nanotube films fabricated on titanium substrates

A novel visible-light-responsive photo-catalyst was synthesized for the photo-degradation of methylene blue. Highly ordered and uniformly distributed titanium dioxide-tungsten trioxide nanotubes on pure titanium substrates were successfully fabricated by one-step electrochemical anodizing and palladium deposited on these nanotubes by photo-reduction method. The resulting samples were characterized by X-ray diffraction, field emission scanning electron microscope, ultraviolet–visible spectroscopy and energy dispersive X-ray spectrometer methods. The degradation of methylene blue (MB) was used as a model reaction to evaluate the photo-catalytic activity of the obtained samples. After irradiated under visible light for 60 min, degradation ratio of Pd-deposited nanotubes was improved as compared with that of bare titanium dioxide-tungsten trioxide nanotubes. Under the same condition, no obvious photo-degradation of methylene blue was found for bare TiO₂ nanotubes. Kinetic research showed that photo-degradation process followed the first-order reaction; the apparent reaction rate constant of Pd-based nanotubes was approximately 2.19 times higher than that on the unmodified nanotubes. The catalysts prepared in this study exhibit industrially relevant interests due to the low cost and high photo-catalytic activity.     

两亲性环糊精的合成研究进展

与天然环糊精相比,两亲性环糊精不仅包结客体分子,而且自组装形成囊状结构,是一类重要的药物载体.本文综述了两亲性环糊精的合成,并对其发展前景进行了展望.     

环糊精催化有机反应的进展

环糊精通过主客体相互作用能将疏水性有机分子转移到对环境友好的水中进行有机反应,还能影响分子的电性环境,使反应在温和的条件下就能获得良好的收率,几乎没有副产物,在有机合成中应用十分广泛。本文就近年来环糊精在有机合成中的催化应用分为氧化、加成、开环、水解、偶联和取代等几种反应类型,并对这些反应进行了概述。     

TiO2/浮石的制备及其光催化性能的研究

以浮石为载体，采用浸渍法制备负载型光催化剂TiO2/浮石，研究微波辅助光催化体系对以活性艳红X-3B的脱色反应，并与Al2O3、分子筛、玻璃细球为载体的光催化剂进行比较.结果显示，微波对TiO2/浮石光催化有辅助作用，TiO2/浮石的催化活性最好.进一步研究了pH、H2O2滴加量，催化剂寿命对TiO2/浮石反应体系的影响，实验证明，TiO2/浮石结构性能稳定，活性持久，适宜于工业应用.     

氮掺杂TiO2/壳聚糖复合膜吸附和光降解染料

氮掺杂二氧化钛/壳聚糖(CS)复合膜是一种有前途的有机染料废水处理材料,相对于传统的废水处理材料更具优势。在模拟太阳光照射下,用氮掺杂二氧化钛/壳聚糖(CS)复合膜对有机染料甲基橙溶液进行降解,通过吸附和光催化的双重作用,甲基橙的降解率可达99%。采用X射线衍射(XRD)、扫描电子显微镜(SEM)等对复合膜进行了表征,并通过傅里叶红外光谱(FT-IR)分析表明其壳聚糖中活性官能团 NH₂, OH在氮掺杂TiO₂ 复合膜中同时存在。研究表明,氮掺杂二氧化钛/壳聚糖(CS)复合膜是一种高效节能的污水处理材料。     

丙烯腈生产用催化剂研究进展

丙烯腈是重要的化工基本原料,丙烷氨氧化制丙烯腈反应工艺是潜在的具有较大经济效益的丙烯腈生产路线。本文介绍了丙烯腈的国内外生产情况,叙述了生产丙烯腈用催化剂的制备、性能和应用前景。