The Effect Of Cucurbit[7]uril On The Self-assembling Behavior Of Cationic Surfactants

Supramolecular chemistry is a subject whose research object is a kind of aggregate that is complicated,orderly under the condition of non-covalent bond weak effort jointing,also a kind of chemistry researching supramolecular or supramolecular chemistry's properties and application.In recent years, supramolecular chemistry has received much attention because of their unique structures and unusual properties different from those of conventional covalent polymers.In supramolecular chemistry area,cucurbiturils,known as 'the new fourth generation supramolecule' after crown either,cyclodextrin and calixarene,is a kind of neotype host.It can recognize guests including metal ions and organic molecules via supramolecular interactions because of its unique cavity structure.It has great application potentiality in the molecular recognition,molecular self-assembly,molecular catalysis,pollution water treatment,mimic enzyme and drug pilot carrier.So,the new kind of host is arousing more and more researchers' considerable interest.Surfactant can form a variety of association colloid and interface,such as micelles,capsules,single-layer and multi-molecular film,through molecular self-assembly.It has a special structure,high-performance,and also its size is in the nano area.It exposes the difference from molecular characteristics,and the difference from the bulk of the material characteristics of referral.It is closely related to the subjects,such as material,life,energy and the environment.So it attracts people's attentions extremely.Surfactant molecule has the structure of a hydrophilic end and a hydrophobic end,Its hydrophobic chain can be linked, through the hydrophobic(major role),into the main compound of a cavity and form the main important - the object of the envelope.Thus surfactant is a kind of important elements of the object.Based on the previous others' studies,the interaction between cationic surfactants and cucurbit[7]uril in water have been investigated by conductance,Surface tension methods.This work is a part of the subject which is funded by the National Natural Science Fund(No.20703023 ).The main contents and the results of this paper are as follow:1.By employing acid catalysis method,glycoluril,as the raw material for cucurbituril synthesis,is synthesized.The effect of different reaction condition on purity and yield of glycoluril,including relative amounts of reactions(urea and glyoxal),PH,reaction time and dropping rate of glyoxal,were studied.2.The synthesis and separation CB[n]have been studied.According to their different solubility in the same solution(HCl solution or methanol aqueous solution),CB[n]can be synthesized by condensation of glycocuril and formaldehyde in concentrated HCl,and then can be separated and purified one by one.The products were determined by elemental analysis,HNMR and ESI-MS.3.The conductivities of systems of cationic surfactants(CTAC or CPC) + CB[7]+ H₂O have been determined at 298.15 K by a DDS-12A digital conductivity meter.Apparent critical micelle concentrations has been determined.It is shown that the associations between CB[7]and the cationic surfactants(CTAC or CPC) are strong.4.The surface tension of systems of cationic surfactants(CTAC or CPC) + CB[7]+ H₂O have been determined at 298.15 K by a BYZ-1 digital surface tensiometer.Apparent critical micelle concentrations has been determined.It is also shown that the associations between CB[7]and the cationic surfactants(CTAC or CPC) are strong.5.1:1 complex of surfactant and CB[7]was formed in solution.It is shown that CB[7]screens hydrophobic chain of the cationic surfactants from contacting with the surrounding media and retards the formation of surfactant micelles in a certain extent.