一个强荧光三维超分子有机框架的构建及其对苦味酸的选择性传感

在四苯基甲烷外侧通过C=C双键引入四个N-甲基-4-苯基吡啶盐片段,合成了一个新的全共轭单体T-1.其在水中与2 equiv.的葫芦脲[8]结合,形成了新的高强荧光的超分子有机框架SOF-r-SPP.动态光散射实验表明,在T-1浓度为1.0和0.031 mmol/L时,SOF-r-SPP的流体力学直径分别为68和41 nm.粉末X-射线衍射实验揭示,SOF-r-SPP形成孔径为2.3 nm的三维金刚石型周期性结构.硝基苯衍生物能有效淬灭SOF-r-SPP的荧光.在17个研究的硝基苯类分子中,苦味酸的淬灭效率最高. SOF-r-SPP作为荧光传感器,对苦味酸的检测极限可以达到0.024 mmol/L.     

Molecules-Receptors: Different Approaches to Design Effective Catalysts

The results of studying a number of reactions catalyzed by system based on macrocyclic receptors are presented. Rh complexes with modified calix[6]- and calix[4]arene were active in the hydroformylation of unsaturated compounds. Ru catalytic system based on cucurbit[6]uril was studied in hydrogen transfer hydrogenation of water insoluble aldehydes. Molecular imprinting method application for design of catalytic systems based on cyclodextrins for naphthols dimerization and oxidative coupling styrene and benzene were discussed.     

From Packed “Sandwich” to “Russian Doll”: Assembly by Charge‐Transfer Interactions in Cucurbit[10]uril

As the host possessing the largest cavity in the cucurbit[n]uril (CB[n]) family, CB[10] has previously displayed unusual recognition and assembly properties with guests but much remains to be explored. Herein, we present the recognition properties of CB[10] toward a series of bipyridinium guests including the tetracationic cyclophane known as blue box along with electron‐rich guests and detail the influence of encapsulation on the charge‐transfer interactions between guests. For the mono‐bipyridinium guest (methylviologen, MV ²⁺), CB[10] not only forms 1:1 and 1:2 inclusion complexes, but also enhances the charge‐transfer interactions between methylviologen and dihydroxynaphthalene ( HN ) by mainly forming the 1:2:1 packed “sandwich” complex (CB[10] ? 2 MV ²⁺ ?HN ). For guest 1 with two bipyridinium units, an interesting conformational switching from linear to “U” shape is observed by adding catechol to the solution of CB[10] and the guest. For the tetracationic cyclophane‐blue box, CB[10] forms a stable 1:1 inclusion complex; the two bipyridinium units tilt inside the cavity of CB[10] according to the X‐ray crystal structure. Finally, a supramolecular “Russian doll” was built up by threading a guest through the cavities of both blue box and CB[10].     

Preparation of glycoluril monomers for expanded cucurbit[n]uril synthesis

Glycoluril derivatives bearing free ureidyl groups (1) and bis(cyclic ethers) (2) are the fundamental building blocks for the synthesis of cucurbituril, its derivatives, and its congeners. The known derivatives of 1 and 2 fall into two main classes—those bearing alkyl or aryl functional groups on their convex face. In this paper we present a third class of glycolurils, namely those bearing substituents that are electron withdrawing in character. This class of compounds carries carboxylic acid derived functional groups on their convex face and are derived from diesters 1e and 2e. An improved synthesis of 1e and 2e is reported and their modification described. For example, 1e and 2e are converted into secondary amides (10-15) by heating in solutions of the neat primary amines. The secondary amides can be transformed into imides (19-22, 24, 25) by heating with PTSA in ClCH₂CH₂Cl. The isolation of these compounds in pure form in high yields is accomplished by simple and scalable washing or recrystallization procedures. We also present the X-ray crystallographic characterization of bis(cyclic ethers) 2e, 8, and 22. We anticipate that the ready availability of ester, carboxylate, acid, secondary amide, imide, and tertiary amide derivatives of 1 and 2 will expand the scope of the synthesis of cucurbituril derivatives by providing a new class of building blocks with electron withdrawing substituents.     

Synthesis and the crystal structure of a supramolecular adduct of the [Mo3O4(H2O)6Cl3]+ cluster complex with macrocyclic cavitand cucurbituril

The crystalline supramolecular compound of composition {(C₃₆H₃₆N₂₄O₁₂)[Mo₃O₄(H₂O)₆Cl₃]₂}Cl₂·14H₂O was obtained by slow concentration of a hydrochloric solution of the cluster aqua complex [Mo₃O₄(H₂O)₉]⁴⁺ and macrocyclic cavitand cucurbituril (C₃₆H₃₆N₂₄O₁₂). The molecular and crystal structure of the supramolecular adduct was established by X-ray diffraction analysis.     

Synthesis and crystal structure of supramolecular adduct of tetranuclear uranyl chloride aquacomplex with macrocyclic cavitand cucurbituril

Crystals of supramolecular compound {[(UO₂)₄O₂Cl₄(H₂O)₆](H₂OC₃₆H₃₆N₂₄O₁₂)}·4H₂O were obtained under conditions of hydrothermal synthesis from solutions of uranyl(vi) nitrate and cucurbituril in the presence of rubidium chloride. The crystal and molecular structure were determined by X-ray diffraction analysis.     

Self-assembly of a [2]Pseudorotaxane Composed of Cucurbit[6]uril into Linear Pseudopolyrotaxanes by N–H···O, C–H···O and π···π Interactions

The [2]pseudorotaxane of cucurbit[6]uril (Q6) with 1,6-bis(imidazol-1-yl)hexane dihydrobromide was synthesized and its crystal structure was described. The structure of [2]pseudorotaxane was mainly stablized by host–guest C–H···O interactions. Self-assembly of the [2]pseudorotaxane produces infinite one-dimensional chains with intermolecular N–H···O, C–H···O, and π···π interactions; thus, a linear non-covalent pseudopolyrotaxane is formed.     

Synthesis and the crystal structure of the supramolecular complex [Cl3InW3S4(H2O)9]2+ with cucurbituril

The supramolecular complex {[Cl₃InW₃S₄(H₂O)₉]₂(C₃₆H₃₆N₂₄O₁₂)}Cl₄·28H₂O was prepared by mixing solutions of [Cl₃InW₃S₄(H₂O)₉]²⁺ and cucurbituril in hydrochloric acid. The molecular and crystal structure of the resulting complex was established by X-ray diffraction analysis.     

Complex Formation of Crown Ethers with the Cucurbit[6]uril–Spermidine and Cucurbit[6]uril–Spermine Complex in Aqueous Solution

Alkyl amines are able to form complexes with either crown ethers or cyclodextrins or cucurbit[6]uril. The same is known for polyamines such as spermidine and spermine. However, the simultaneous formation of such polyamines with crown ethers and cucurbit[6]uril has not been studied. The ability of polyamines such as spermidine and spermine to form mixed complexes with different ligands, e.g. crown ethers and cucurbit[6]uril has been studied in aqueous solution using pH-metric and calorimetric titrations. The thermodynamic data of reaction between crown ethers with spermidine, spermine and their cucurbit[6]uril complexes have been determined. The presence of cucurbit[6]uril on the polyamines has no important influence upon the reaction of these amines with crown ethers. The reactions between polyamines, cucurbit[6]uril and crown ethers are simple examples for the self organization of molecules due to specific interactions. Received in final form: 26 January 2005