用分子光谱法研究两种水溶性卟啉与磺丁醚-β-环糊精的超分子体系

本文以紫外可见光谱法和荧光光谱法研究了水溶性的四-(4-甲基吡啶基)卟啉(TMPyP)和四-(4-羧基苯基)卟啉(TCPP)与磺丁醚-β-环糊精(SBE--βCD)形成的超分子体系。结果表明,两种卟啉与磺丁醚-β-环糊精都形成了1∶1的包结物,它们的包结常数分别为1.34×104L.mol-1和1.15×105L.mol-1。     

非水溶性卟啉NTPPH_2和ATPPH_2与环糊精超分子体系的光谱学研究

在中性磷酸盐缓冲溶液中,用紫外-可见分光光度法和荧光光谱法研究了非水溶性卟啉5-(4-硝基苯基)-10,15,20-三苯基卟啉(NTPPH2)和5-(4-氨基苯基)-10,15,20-三苯基卟啉(ATPPH2)与α-CD、β-CD和γ-CD三种环糊精相互作用形成的超分子体系。结果表明,NTPPH2与α-CD、β-CD和γ-CD均形成了1:1的包结物,ATPPH2与β-CD形成1:2的包结物,与α-CD和γ-CD则形成了1:1的包结物。其中α-CD与NTPPH2和ATPPH2的包结常数最大。本文探讨了卟啉环上给电子基团和吸电子基团对包结的影响,为卟啉和环糊精相互作用及超分子体系的机理研究提供了基础。     

meso-四(4-甲氧基-3磺酸基苯)卟啉与环糊精超分子体系的研究

采用极谱法、紫外可见光谱法及荧光光谱法研究了水溶性卟啉T(4-Mop)PS4与α-CD、-βCD、γ-CD、Hp-β-CD及SBE--βCD 5种环糊精的相互作用,结果表明T(4-Mop)PS4分别与这5种环糊精形成了T(4-Mop)PS4-CD s超分子体系。此外,本研究还采用极谱法、紫外可见光谱法及荧光光谱法测定了T(4-Mop)PS4-CD s超分子体系的包结常数和包结比,比较了T(4-Mop)PS4与5种环糊精的包结能力,并由此推测了包结机理,为T(4-Mop)PS4卟啉、环糊精的进一步应用提供了理论信息。     

meso-四-(2-噻吩基)铜卟啉-环糊精超分子体系的光谱学研究

以紫外可见分光光度法和荧光光谱法研究了非水溶性meso-四-（2-噻吩基）铜卟啉（简称Cu—TTP）与四种环糊精α—CD、β—CD、γ—CD、TM—β—CD相互作用形成的超分子体系，结果表明Cu-TTP与TM-β-CD形成了1：2的包结物，而与其它三种环糊精主要形成1：1的包结物。在α—CD、β—CD、γ-CD三种母体环糊精中，α—CD与Cu—TTP的包结常数最大；β-CD与其衍生物TM-β-CD相比，TM-β-CD与Cu—TTP的包结常数较大。本文对四种环糊精和Cu-TTP的包结机理作了初步探讨。为铜卟啉和环糊精的相互作用及其超分子体系的研究提供了基础。     

5-邻硝基苯-10,15,20-三苯基卟啉-环糊精超分子体系研究

在中性磷酸盐缓冲溶液中,以紫外-可见分光光度法、荧光光谱法和1HNMR法研究了一种人工合成的非水溶性卟啉5-邻硝基苯-10,15,20-三苯基卟啉(简称o-NTPP)与3种母体环糊精α-CD、β-CD、γ-CD和β-CD的两种衍生物2,3,6-三-甲氧基-β-CD(TM-β-CD)、羧甲基-β-CD(CM-β-CD)之间相互作用形成的超分子体系,结果表明o-NTPP与TM-β-CD形成了1∶2的包结物,而与其它4种环糊精均形成1∶1的包结物。利用双倒数曲线法计算了o-NTPP-CD超分子体系的包结常数(k),同时对包结常数大小进行了比较,从而判断出5种环糊精对o-NTPP包结能力的大小,其中TM-β-CD表现出最强的包结能力。     

用三种不同方法研究TPPS4与DM-β-CD的相互作用

本文以极谱法、荧光光谱法和紫外可见光谱法研究了水溶性卟啉四-(4-磺基苯)卟啉(TPPS4)与2,6-二-氧-甲基--βCD(DM--βCD)的相互作用。结果表明,二者可发生反应,形成了TPPS4-DM--βCD的超分子体系。此外,本文还用极谱法和紫外-可见光谱法对TPPS4-DM--βCD超分子体系的包结比和包结常数进行测定,证明二者形成了1∶2的包结物;计算所得的包结常数为1.44×108L2.mol-2。     

BATPPH_2及其Zn配合物与环糊精的超分子体系研究

设计合成了5-(4-苯甲酰亚胺基苯基)-10,15,20-三苯基卟啉(BATPPH2)及其锌配合物(BATPPZn),并通过1HNMR、IR、UV-Vis、元素分析等方法对化合物的结构加以确认。在中性磷酸盐缓冲溶液中,以荧光光谱法、紫外可见分光光度法和1HNMR法分别研究了BATPPH2和BATPPZn与α,β,γ-环糊精相互作用形成的超分子体系。利用双倒数曲线法计算了BATPPH2-CD和BATPPZn-CD超分子体系的包结常数,结果表明BATPPH2和BATPPZn与γ-CD的包结常数(K1γ-CD,K2γ-CD)最大,γ-CD表现出最强的包结能力,Zn2+的配位作用使包结物的稳定性降低。     

环丙沙星与环糊精超分子体系的研究

利用荧光光谱法研究了环丙沙星与母体β-环糊精(β-CD)及其2种修饰衍生物羟丙基-β-环糊精(Hp-β-CD)、甲基-β-环糊精(Me-β-CD)形成的超分子体系,同时测定了3种超分子体系的猝灭常数和热力学参数.结果表明:环丙沙星与3种环糊精之间常温下均形成稳定的包合物;环丙沙星与3种环糊精包结过程中△G＜0和△H＜0,这说明环丙沙星与3种环糊精的包结能够自发进行而形成超分子体系,且反应为放热过程.通过对3种环糊精与环丙沙星的热力学数包结能力进行了比较,初步探讨了作用机理和影响包结能力大小的可能因素.     

环糊精-卟啉超分子体系的构筑及应用进展

环糊精具有分子识别和选择包结客体分子的独特性质,而卟啉具有模拟酶催化、电子转移和光能转移等功能,本工作通过对环糊精-卟啉超分子体系构筑方式的介绍,详细综述了环糊精-卟啉超分子体系在模拟酶催化、生命科学、药物控释、电子转移过程等方面的应用,认为环糊精-卟啉超分子体系具有卟啉和环糊精双重性质的优点,而以键联环糊精-卟啉为主体分子构筑的超分子体系能更有效地模拟生物酶,表现出优异的区域和立体选择性,在仿生催化方面将具有更广泛的应用前景.     

用3种不同方法研究铬黑-T与β-CD的相互作用

本文以极谱法、荧光光谱法和紫外可见光谱法研究了铬黑-T与β-环糊精(β-CD)的相互作用。实验结果表明,二者可发生作用,形成铬黑-T-β-CD的超分子体系。此外,本文还分别采用极谱法和紫外可见光谱法对铬黑-T-β-CD的超分子体系的包结比和包结常数进行测定,包结比为1∶1,包结常数为6.05×106L/mol,并初步推断了铬黑-T和β-CD的结合形式。     

Solid-supported monolayers and bilayers of amphiphilic beta-cyclodextrins

This paper describes the adsorption and spreading of beta-cyclodextrin (CD) vesicles on hydrophobic and hydrophilic substrates, which involves a transition from bilayer vesicles to planar molecular monolayers or bilayers. On substrates that are patterned with self-assembled monolayers by microcontact printing (muCP), the CD vesicles preferentially adsorb on hydrophobic areas instead of hydrophilic (nonionic) areas, and on cationic areas instead of hydrophilic (nonionic) areas. Supported monolayers of amphiphilic cyclodextrins CD1 and CD2 were obtained by adsorption of CD vesicles to hydrophobic substrates, and supported bilayers of amphiphilic cyclodextrins CD1 and CD2 were prepared by adsorption of CD vesicles on cationic substrates. Contact angle goniometry, atomic force microscopy and confocal fluorescence microscopy (CFM) were used to analyze the supported CD layers. The fluidity of the supported CD layers was verified using fluorescence recovery after photobleaching experiments. The supported layers function as a supramolecular platform that can bind suitable guest molecules through inclusion in the CD host cavities. Additionally, the CD host layers were patterned with fluorescent guest molecules by supramolecular muCP on the supported CD layers. The host-guest interactions were investigated with CFM and fluorescence resonance energy transfer experiments.     

环糊精超分子包络物的相变行为及其热分析研究进展

本文概述了近年来国内外报道的关于环糊精(CD)超分子包络物的相变温度与热释出行为和主客体结构之间的关系.基于这些文献中热重、差示扫描量热和气相色谱耦合时间飞行质谱等方法提供的CD超分子包络物的热力学数据比较发现,在超分子包络物中CD与客体的相变温度及客体的释出形式依赖于客体被包结前的物相与主客体分子间相互作用的强度.客体的类型如:形态、结构、极性和体积等都会影响主客体之间的相互作用,进而导致包络物展现不同的相变和热释出温度.而且,主客体分子间的相互作用越强,超分子包络物的释出温度越高.     

Fluorescence Dynamics of Monocyclodextrin– and Bis(thiol‐cyclodextrin)–Coumarin C153 Complexes

The solvation and confinement of coumarin C153 within supramolecular host/guest complexes based on β‐cyclodextrin (β‐CD) and 6‐deoxy‐6‐thio‐β‐cyclodextrin (β‐CD‐SH) in water are studied by fluorescence spectroscopy. For β‐CD/C153, the 1:1 complex is proposed, and for β‐CD‐SH/C153 both the 1:1 and 2:1 complexes are believed to be formed. The 2:1 β‐CD‐SH/C153 complex has an association constant of 4.2×10⁵ M ^?1 and a C153 population of 82 %, which are interestingly high values, indicating that the proposed β‐CD‐SH dimers structure are connected by covalent disulfide bonds; this is supported by mass spectrometry. Solvation related to fast hydrogen‐bond rearrangement as a part of fluorescence relaxation is determined by the ultrafast components of time‐resolved spectroscopy to be 3 and 7 ps for the 1:1 β‐CD/C153 and 2:1 β‐CD‐SH/C153 complexes, respectively.     

A fluorescence study of tetraphenylporphyrinatozinc(II)/imidazolyl-linked porphyrinatoiron(III) systems

The fluorescence spectra of porphyrinatozinc(II)/iron(III) systems which consisted of tetraphenylporphyrinatozinc(II) and three kinds of imidazolyl-linked porphyrinatoiron(III) have been studied. An efficient fluorescence quenching of tetraphenylporphyrinatozinc(II) in the system was observed. Addition of a stronger organic base, such as piperdine, to the system can displace imidazolyl-linked porphyrinatoiron(III) and the fluorescence of the system restored partly. All these indicate the formation of porphyrinatozinc(II)/iron(III) supramolecular complex and coordination bonding formed by the coordination of imidazolyl group in imidazolyl-linked porphyrinatoiron(III) to Zn(II) in tetraphenyl-porphyrinatozinc(II) is the driving force of the supramolecular self-assembly. The association constants of the supramolecular complexes were calculated from the fluorescence spectroscopic titration data, and the differences among the association constants of the supramolecular complexes are discussed on the basis of the conformations which are dependent on the length of alkoxy chain linking imidazolyl group to porphyrinatoiron(III).     

Spectrofluorimetric study on the inclusion interaction between lomefloxacin and p-sulfonated calix[4]arene and its analytical application

The characteristics of host-guest complexation between p-sulfonated calix[4]arene (SC4A) and lomefloxacin (LMFX) were investigated by fluorescence spectrometry. A 1:1 stoichiometry for the complexation was established and an association constant of 6.48x10(4) l mol-1 at 25 degrees C was calculated by applying a deduced equation. The interaction mechanism of the inclusion complex was discussed and the various factors affecting the inclusion process were examined in detail. It was found that an appropriate amount of cationic surfactant cetyltrimethylammonium bromide (CTAB) can remarkably enhance the fluorescence intensity of the supramolecular complex system. Based on the obtained results, a novel sensitive spectrofluorimetric method for the determination of lomefloxacin based on supramolecular complex was developed with a linear range of 0.01-3.0 microg ml-1 and a detection limit of 0.008 microg ml-1, for the first time. The method was applied for the determination of lomefloxacin in pharmaceutical preparations successfully.     

Highly fluorescent chameleon nanoparticles and polymer films: multicomponent organic systems that combine FRET and photochromic switching

We describe the preparation of highly efficient stimulus-responsive fluorescence color-tuning in self-assembled supramolecular scaffold systems. The systems consisted of a photochromic compound (BP-BTE) in combination with unique luminescent organic materials (CN-MBE, TPS-CNMBE, TPA-2CNMBE) that exhibited intense fluorescence in the solid state. The emission spectrum was tuned by introducing fluorescence resonance energy transfer and photochromic switching capabilities into the system. The materials were used to successfully demonstrate novel fluorescence patterns that were responsive to multiple stimuli, displayed reversible fluorescence switching, and provided a nondestructive readout of the fluorescence signal.     

Host–guest interaction-mediated fabrication of aggregation-induced emission supramolecular hydrogel for use as aqueous light-harvesting systems

ABSTRACT

Aqueous light-harvesting systems in hydrogels formed by specific noncovalent interactions exhibit both solution and solid-state performance. In this work, the copolymerisation of acrylamide (AM), 4-(1,2,2-triphenylvinyl) phenyl acrylate (vTPE), and guest units 1-benzyl-3vinylimidazolium (G) was carried out with initiator to form P(AM-vTPE-G). Then, supramolecular hydrogels were fabricated by dynamic host–guest interactions the guest unit and host molecule cucurbit[8]uril (CB[8]). The aggregated tetraphenylethylene (TPE) moieties in the polymer chains aggregate together, possessed high fluorescence enhancement during the cross-linking process. Meanwhile, emission characteristics of the obtained aqueous light-harvesting systems were further examined by using the donor (supramolecular hydrogel) and acceptor (Eosin Y disodium salt) system. The process provides a novel method for the production of fluorescence and self–healing supramolecular hydrogel with various potential applications.     

Dynamics of Supramolecular Association Monitored by Fluorescence Correlation Spectroscopy

Supramolecular binding is a key process in many biological systems and in newly developed supramolecular assemblies. Most of the scientific work on these systems is focused on their structural properties and on the thermodynamics of the association process. However, the underlying dynamics are usually much less known, in spite of the great importance they have during the binding process in these highly dynamic systems. Understanding supramolecular binding in biological systems and controlling the functionality of new synthetic supramolecular systems can only be achieved through knowledge of the structure–dynamics relationship. There is a strong need for suitable techniques which cover the typically wide time interval of the association dynamics and which do not need a perturbation of the system. We briefly review high‐resolution fluorescence correlation spectroscopy (FCS) as a technique to monitor supramolecular dynamics and to give information on how structure determines the dynamics of host–guest association. The comparison of hosts and guests with different structures shows that geometrical and orientational requirements determine the association rate constant, whereas the dissociation is defined by the strength of specific interactions. As model hosts cyclodextrins and micelles are studied.