Synthesis And Properties Of Macro-cycle Based Functional Supramolecular Pseudorotaxane Polymer

Supramolecular polymers are defined as polymeric arrays of monomeric units that are brought together by reversible and highly directional secondary interactions, resulting in polymeric properties in dilute and concentrated solutions, as well as in the bulk. The monomeric units of the supramolecular polymers themselves do not possess a repetition of chemical fragments. The directionality and strength of the supramolecular bonding are important features of systems that can be regarded as polymers and that behave according to well-established theories of polymer physics.Supramolecular polymers, the combination of supramolecular chemistry and polymer science, can be defined as polymeric systems that extend beyond the molecule and utilize noncovalent interactions to direct their assembly, to control their conformations, and/or to define their behavior. Due to the reversibility of noncovalent interactions, these materials are capable of undergoing self-healing and adaptation processes, which afford supramolecular polymers a major advantage over conventional, covalently bonded polymers. The responsiveness to external stimuli may further provide a range of potential applications such as smart/adaptive materials and devices.In Chapter one, the progress of fuctional supramolecular pseudorotaxane polymer was reviewed. It demonstrated the definition of supramolecular polymer, types of stimuli responsive supramolecular polymer and their promising application. The emphasis of review was paid to molecular machines based supramolecular polymer, and systematically introduced various functional supramolecular polymer based on cyclodextrin, calixarene, cucurbit and other macrocyclic system.In Chapter two, the host-guest interaction based on calixarene derivatives are relatively less explored in supramolecular polymers, while crown ethers and cyclodextrins as relatively common host monomer units has been studied systematically. We report here the formation of a novel fluorescent supramolecular polymer formed from two complimentary monomers which contain p-sulfonatocalix[4]arene based homoditopic receptor and the viologen and dimethylamino connectors decorated with a fluorophore. The fluorescent polymer can response to both electrochemical redox and pH variance, engendering two kinds of pseudorotaxanes formed as unimers induced by respective stimuli. Despite some calixarene-based supramolecular polymers in previous and more recent works, no such reversibly controlled electrochemical and pH dual-responsive fluorescent system has been reported before. Moreover, it novelly involves two disparate pseudorotaxanes as unimers in the reversible assembly/disassembly process of supramolecular polymer. The assembly/disassembly process of polymer, reversibly controlled by electrochemical and protonation/deprotonation can be conveniently addressed by fluorescence emission variance and induced circular dichroism (ICD) signals.In Chapter three, the charge-transfer (CT) interactions and donor-acceptor interactions between π-systems have become important classes of non-covalent interactions, and been greatly exploited in the design and synthesis of self-organizing systems. The organization of alternating electron-rich and electron-deficient units has also been employed to create novel macromolecules with folded structures. The properties of a supramolecular polymer can be adjusted by modulating the properties of its relevant monomers. Combining the well-known properties of macromolecule with supramolecular polymer has an enormous potential to alter the properties of polymer in a controlled way. By involving different pseudorotaxanes in reversible stimulus-responsive supramolecular polymer, we can enormously open the way of exploring potentially applicable aspects of supramolecular polymers as data memories and logic functions in nanoscale. We report here the formation of a novel fluorescent and high polymerized supramolecular polymer based on host-stabilized CT interactions between a viologen dication connector and a cyano-stilbene fluorophore decorated with dimethylamino portion. The fluorescent polymer can be formed by bringing the monomer’s donor and acceptor units of close proximity inside the CB[8] cavity, resulting in a stable intermolecular CT complex stabilized by CB[8]. At the same time, because that the properties of the polymer are affected by the relevant monomers, the polymer can response to both electrochemical redox and pH variance, with two kinds of pseudorotaxanes formed as monomers when induced by respective stimuli.In Chapter four, the ability to control molecular self-assembly with tailored properties by non-covalent interactions is a major driving force in the bottom-up nanofabrication of molecular devices. Photoresponsive monomer molecules can provide a path to remotely control the resulting supramolecular polymer morphology or formation by light. Chiral monomers can impart chirality into the supramolecular polymers to form chiral suprastructures which may exhibit some fascinating chirooptical properties. Light-driven linear chiral supramolecular polymer was constructed in water by host-guest molecular recognition between bis-p-sulfonatocalix[4]arenes and the α-cyclodextrin based pseudo[3]rotaxane containing axially chiral1,1’-binaphthyl and photoresponsive azobenzene moieties. The successful supramolecular polymerization by non-covalent host-guest molecular recognition was confirmed by1H NMR, and its photoresponsive behavior was investigated by UV-vis absorption spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The chirality of this supramolecular polymer was confirmed by circular dichroism spectra. The dramatic morphology change of this chiral polymer driven by light was observed in TEM and SEM images. More interestingly, the dynamically self-assembled, light-driven single linear helical supramolecular polymer with a length of hundreds of nanometers to micrometers in water was directly observed in its native state using Cryo-TEM measurements.In Chapter five, cyclodextrin (CD), cucurbituril (CB) and calixarene, as three different host macrocycle compounds provided with special structures and disparate supramolecular inclusion performances respectively, have been extensively employed to construct rotaxanes and pseudorotaxanes. Many rotaxanes or pseudorotaxanes incorporating two or more components in one interlocked system (either rotaxane oligomer or not) have been constructed in recent years. However, there were only a few rotaxanes or pseudorotaxanes incorporating two or more different host macrocycles in one system. The very known phenomena have been reported that a-CD can encircle on such moieties as stilbenzene and azobenzene in aqueous solution, CB[7] and SC4prefers to bind4,4’-bipyridinium (viologen) dication units with very high association constants. Then combining the dumbbell with a-CD, CB[7] and SC4in various combination modes, we constructed the pseudo[2]rotaxane R, pseudo[3]rotaxanes R1and R2, pseudo[4]rotaxanes R1’, R2’and R3. The three pseudo[4]rotaxanes could be also regarded as a-CD based rotaxanes to some extent because its two end parts, included by CB[7] or SC4with very high association constants, could be used to stop a-CD slipping away from RO. In particular, the pseudo [4]rotaxane R3consists of one inclusion part between a-CD and the azobenzene moiety and another two inclusion sites between CB[7], SC4and4,4-bipyridinium units respectively. As far as we know, it is the first example that the three hetero-macrocycle (a-CD, CB[7] and SC4) host are incorporated in one supramolecular pseudorotaxane system. The constructions of these complicated supramolecular systems may set up new basis for exploiting future molecular devices with multiple functions.In Chapter six, synthetic chemistry plays a key role in the advancement of material sciences and life sciences, and its key point is to utilize those materials into practice is the process of mechanization. Our group has done a lot of work on kinds of functional molecular machines in solutions, while rare in solid and mechanization. So it is necessary for us to connect our abundant synthesizing experiences in molecular machine and the research in liquid crystal material, to improve the development of both fields and capture some intractable scientific problems and create new fields in the mechanization of supramolecular system and application of functional liquid crystal materials. We designed and sythesised kinds of liquid crystal dopant material based on molecular machine and cyclic chiral system, and tested its HTP by dopanting them in liquid crystal.In Chapter seven is the conclusion.