Synthesis And Self-Assembly Of Calix[4]Arene And Tetraphenylethylene Macrocycles

Macrocycles, with their inner cavity, are easily to form nanopores or to establish new nano-channels created by the stacking of macrocycles through self-assembly thanks for various weak intermolecular interactions between macrocyles. The channel size and function of the assembly can be fine tuned by different means; hence, they are received intense application in the fields of ion-channel, molecule sensor, vehicle of pharmaceuticals and biosensors. However, hitherto only very few reports are about the self-assembly of macrocycles as well as their functions, especially those self-assembly porous materials with fascinating functions. Still, the design and synthesis of functional macrocycles remains challenge. The lack sufficient understanding of the mechanism of self-assembly behavior of macrocycles was, of course, a reason to raise the challenge for molecule design. In order to endow the self-assembly material with the function to analysis and monitor the process of self-assembly and its deassembly, molecule recognition process and cargo loading and release behavior, functional groups must introduced into the macrocyces.1. Several amine and carboxylic acid calix[4]arenes amphilphiles were designed and prepared. The morphology of the self-assembly between amine calix[4]arenes and L-dibenzoyl tartaric acid can be controlled by the length of alkyl chain of the lower ring of amine calix[4]arenes as well as their conformation, the stoichiometric with the acids and solvent. Carboxylic acid calix[4]arene8a can form thermo responsive gel in ethanol water mixture. Mesoporous silica nanospheres prepared from8d as a template have potential application in gas absorption and catalysis. The self-assemblies of compound17can be used as template to prepare silica void spheres which can be used as pharmaceutical vehicle and controlled release material.2. Several tetraphenylethylene crown ether macrocycles which have aggregation induced emission behavior were prepared and their self-assembly nature were investigated. Compound25b can self-assembly into nanorods, nano solid spheres and void spheres in THF and water mixture with different volume ratio. The nanospheres can be transformed into net formed by nanorods under ultrasound for1.5hours and the emission turned from green to blue in the mean time. In higher water ratio solution, the tetraphenylethylene crown ether macrocycles will precipitate faster and hence unable to stacking symmetrically that leads to the formation of nonospheres. Sphere like aggregates emission at longer wavelength which result from the smaller dihedral angle between different phenyl rings of tetraphenylethylenes that have better conjugation. However, the smaller dihedral angle will cause inner strength and hence unstable. After ultrasonic or kept longer time, they will transforme into more stable nanorods. The morphology transformation under ultrasonication can be used to loading and controlled releasing of anticancer drug carbohydrazide. 3. A serial of tetraphenylethylene amide macrocycles were synthesized and proved to have mechanochromic behavior. In the crystalline state, tetraphenylethylene amide macrocycles are enforced to twisting between phenyl rings that the conjugation between phenyl rings and double bonds are weakened. After the crystal lattice had been broken by force, the twisting strength and crystal lattice confinement are released that the molecule will reinforce the conjugation by a plane conformation. Hence, the emission shift to longer region and may receive potential application in optics materials. The self-assembly behavior reveled that44b can form nanotube from nano fibers twising along axis in70%THF/water mixture. And the nano fibers can further twising into stable nanosphere with a hole if water increased to95%. This material is looking forward to be used in drug loading and controlled release.