Dissertation
Dissertation > Medicine, health > Pharmacy > Drug basic science

Structure and properties of cucurbituril and drug molecular self-assembly system

Author MouLan
Tutor XueSaiFeng;TaoZhu
School Guizhou University
Course Pesticides
Keywords cucurbiturisl pharmaceutical molecules molecular assembly and molecular recognition room temperature phosphorescence
CLC R91
Type PhD thesis
Year 2007
Downloads 343
Quotes 3
Download Dissertation

Nowadays supramolecular chemistry has become one of the hot fields of chemical research. Cucurbit[n]uril, Q[n], is a relatively new family of macrocyclic host molecules. They are rigid macrocycles with a unique cavity, rimmed by carbonyl oxygens. Ingress and egress of guests is controlled by the size of the carbonyl portal. Cucurbit[n]urils can form inclusion complexes with organic guests, with the strongest complexes formed with positively charged guests. Moreover, the strong chemical stability of cucurbiturils makes it useable in many much hardly environment of medium and condition. So, it is attracted widely attention which the cucurbit[n]url chemistry have been by the researcher all of the world in the research fields of host-guest chemistry, molecular assemblies and molecular recognition superamolecular chemistry, environmental chemistry, catalysis, material chemistry and biochemistry.Cucurbit[n]ur as a new number of macrocyclic host molecules, the application of molecular assemblies and recognition in pesticide and medicament foundation research is a newness field. Explore the application of cucurbit[n]ur in explore stabilization, dissolution of pesticide and medicament is very importance. This will develop a new field for cucurbit[n]url chemistry and provide new thoughtfulness for new pesticide development. This research is believed to be significant for new application field for cucurbit[n]url chemistry, for new remedy design, new remedy carrier.Base on the pharmic research meaning of cucurbit[n]url and quinoline derivates, some quinoline derivates were selected as objects, the characters of interaction between difference cucurbit[n]url and quinoline derivates were studied. The abilities of molecular assemblies and recognition of cucurbit[n]url for quinoline derivates were reviewed. To explore the possibilities of application foundation in the research field of pharmacy and pharmic analysis for cucurbiturils macrocyclic host molecules for purposes.The interaction of cucurbit[n =6,7,8]urils(Q[6],Q[7],Q[8]) with some quinoline derivates which are 2-phenylquinoline, N-propylquinoline, 3-aminoquinoline and 7,8-phenylquinoline were studied by using 1H NMR technique and fluorometric analysis. The experimental results of both methods reveal that 2-phenylquinoline can form stable inclusion complex with Q[6], Q[7], Q[8] with a ratio of 1:1, 1:1 and 2:1 respectively, and the inclusion constants of 2-phenylquinoline-Q[6] or Q[7] was 1.6×104 and 3.2×103 L·mol-1 respectively. 1H NMR results also showed that Q[6], Q[7], Q[8] could form inclusion complex with N-propylquinoline with a ratio of 2:1 respectively, and Q[7] could form inclusion complex with 7,8-phenylquinoline with a ratio of 1:1. Fluorometric analysis reveal that the host-guest . complexes of Q[8] and the title quinoline derivates were formed with a ratio of 1:2 respectively, and the fluorescence of the interacted quinoline derivates was queched by Q[8]. Also the interaction models were suggested for above host-guest inclusion complexes.For the first time, the observation of cucurbit[n]urils induced room temperature phosphorescence of quinoline compounds due to the formation of ternary inclusion complexes between cucurbit[7 or 8]uril, quinoline derivatives, and heavy atoms in aqueous solution. The effects of the variation of concentrations of major component in the systems on RTP of these luminophore, pH values, the RTP lifetime of the Q[n] induced RTP systems had been investigated and compared. In presence of Na2SO3, the RTP lifetimes of luminophore/Q[8]/KI were generally longer than that of luminophore/Q[8]/TlNO3, while the cation Tl+ was stronger RTP enhancer. Contrary to the stable 1:2 Q[8]:guest ternary inclusion complexes at lower pHs, a lower Q[8] induced RTP was observed. However, at higher pHs, high intensity of Q[n]-induced RTP of these quinoline derivatives were observed, and a 1:1 Q[8]:guest inclusion complex was formed. Investigations of dependence of RTP intensity on concentration of Q[n] revealed that the highest intensity of the Q[n] induced RTP was observed at a low mole ratio of host:guest, which is closed to 1:1. It was presumably resulted from the strong interaction of Q[n] and these guests due to the combined hydrophobic cavity interaction and the hydrophilic portal interaction of the cucurbit[n]urils with the nitrogen heterocydes guest. The experimental results also showed that the Q[n] induced RTP systems had good analytical characteristics, a method for determination of these quinoline or its derivative by Q[n)-RTP could exploited the application sphere of Q[n]-RTP. The experimental results showed that Q[7] can not induce RTP for all of these quinoline derivatives, but only selected ones. However, Q[8] can induce RTP for all of these quinoline derivatives. This showed the molecular recognition ability of cucurbit[n]urils. The RTP lifetimes of luminophore/Q[7 or 8]/KI were generally longer than that of luminophore/Q[7 or 8]/TlNO3, the RTP lifetimes of these systems were between 0.18 and 47.4 ms. So it was possible to establish the analysis method of molecular recognition or time distinguish for the medicament according to the different cucurbit[n]urils or different heavy atoms. also formed between Q[6] and gurst 44 and its derivates. The interaction model of Q[n] with herbicide model molecules was explored.Base on the cucurbiturils shows a highly symmetrical structure with two identical openings, not only the hydrophobic interior but also the carbonyl groups surrounding portals of cucurbiturils provides two recognition sites, make the formation of highly stable inclusion complexes possible. Producing nanostructured films via the layer-by layer (LBL) technique. This technique allows fine-tuning of thickness and supramolecular architectures with the added advantage of experimental simplicity. Naphthalene(Nath) as a fluorescence probe was included with Q[8], chitosan(CS) was a molecular crosslinker. The Nath-Q[8]-CS alternation deposition films were investigated on quartz glass. Ferrocene(Fc) as an electrochemical probe was included with Q[7], Au-nanoparticle was a molecular crosslinker. The Fc-Q[7]-Au alternation deposition films were investigated on indium-doped tin oxide(ITO) glass. The structures of alternation deposition films were characterized by UV absorbance spectroscopy, fluorescence spectroscopy and cyclic voltammetry. This is a kind of nanostructured multi-layer luminescence or conduction films, there were potential applications in analytical, pharmacy and material chemistry.For the first time, using cucurbit[7]uril macrocycle as protective sheath, stable and insulated polyaniline molecular wires were successfully fabricated by the polymerization of the inclusion complex of aniline with cucurbit[7]uril, and characterized using different methods. At first, the formation of an inclusion complex between Q[7] and aniline (AN) monomer was clearly evident from 1H NMR,UV and fluorescence spectroscopy titration study, experiments data investigation also confirmed the formation of 1:1 Q[7]- AN complex. The correct threading of PAN wire into CB[7] macrocycles was confirmed by using FTIR. The direct visualization of the encapsulated PAN wires were observed by AFM. Measured from AFM image, these molecular wires exhibit nearly uniform vertical height of 2nm, which is comparable to the outside diameter of Q[7]. we have demonstrated to use Q[n] macrocycles as insulating sheath to fabricate the polyaniline based nanocables by in-situ polymerizing Q[7]-aniline inclusion complex. Due to the highly symmetrical structure and multiple recognition models of Q[n], the polyaniline threading pseudorotaxane structure is found to exhibit remarkable stability, indicating that Q[n] macrocycle is very suitable for the development of insulated molecular wire without stoppers at both ends. This is the first report also formed between Q[6] and gurst 44 and its derivates. The interaction model of Q[n] with herbicide model molecules was explored.Base on the cucurbiturils shows a highly symmetrical structure with two identical openings, not only the hydrophobic interior but also the carbonyl groups surrounding portals of cucurbiturils provides two recognition sites, make the formation of highly stable inclusion complexes possible. Producing nanostructured films via the layer-by layer (LBL) technique. This technique allows fine-tuning of thickness and supramolecular architectures with the added advantage of experimental simplicity. Naphthalene(Nath) as a fluorescence probe was included with Q[8], chitosan(CS) was a molecular crosslinker. The Nath-Q[8]-CS alternation deposition films were investigated on quartz glass. Ferrocene(Fc) as an electrochemical probe was included with Q[7], Au-nanoparticle was a molecular crosslinker. The Fc-Q[7]-Au alternation deposition films were investigated on indium-doped tin oxide(ITO) glass. The structures of alternation deposition films were characterized by UV absorbance spectroscopy, fluorescence spectroscopy and cyclic voltammetry. This is a kind of nanostructured multi-layer luminescence or conduction films, there were potential applications in analytical, pharmacy and material chemistry.For the first time, using cucurbit[7]uril macrocycle as protective sheath, stable and insulated polyaniline molecular wires were successfully fabricated by the polymerization of the inclusion complex of aniline with cucurbit[7]uril, and characterized using different methods. At first, the formation of an inclusion complex between Q[7] and aniline (AN) monomer was clearly evident from 1H NMR,UV and fluorescence spectroscopy titration study, experiments data investigation also confirmed the formation of 1:1 Q[7]- AN complex. The correct threading of PAN wire into CB[7] macrocycles was confirmed by using FTIR. The direct visualization of the encapsulated PAN wires were observed by AFM. Measured from AFM image, these molecular wires exhibit nearly uniform vertical height of 2nm, which is comparable to the outside diameter of Q[7]. we have demonstrated to use Q[n] macrocycles as insulating sheath to fabricate the polyaniline based nanocables by in-situ polymerizing Q[7]-aniline inclusion complex. Due to the highly symmetrical structure and multiple recognition models of Q[n], the polyaniline threading pseudorotaxane structure is found to exhibit remarkable stability, indicating that Q[n] macrocycle is very suitable for the development of insulated molecular wire without stoppers at both ends. This is the first report about the construction of the conjugated polyrotaxane based on Q[n] macrocycle. No matter how the research of assembly techniques for layered film or for the molecular wire, the purpose was to explore the possibilities of application foundation in the research field of mechanism catch and slower release, function material or sensor for cucurbiturils macrocyclic host molecules.

Related Dissertations
More Dissertations