The development of new and efficient polymerization methodologies to access macromolecules with novel structures and unique functionalities is of great academic significance and industrial implication. Multicomponent polymerizations (MCPs), which are derived from the powerful synthetic masterpiece of multicomponent reactions (MCRs), offer new possibilities for the preparation of functional macromolecules with well-defined structures. Inherited from MCRs, MCPs possess the advantages of high efficiency, atom economy, low waste, etc. Furthermore, the tandem strategy, which combines multiple steps in one synthetic operation and delivers elegant synthesis towards desired skeletons, can be adopted into the MCPs to develop efficient multicomponent tandem polymerizations (MCTPs), which can avoid the intermediate isolations, improve the synthetic efficiency and reduce the cost. The MCPs and MCTPs are able to afford a library of conjugated macromolecules with varied functionalities from simple precursors and procedures, which are difficult to achieve by other synthetic methods. Generally, acetylenic monomers are a class of facile building blocks for the preparation of n-conjugated polymers and the acetylenic polymerizations have emerged as versatile techniques for the construction of diverse specialty polymeric materials. Thus, in this thesis work, I have launched a program for the exploration of new efficient MCPs and MCTPs from acetylenic monomers to synthesize acetylenic polymers with advanced functionalities. The alkyne-based MCP and MCTP approaches have been successfully developed in Chapters II-VIII: (1) Cu-catalyzed MCPs of aromatic diynes, disulfonyl azide and optically active amino esters, (2) multicomponent click polymerizations of diyne, disulfonyl azide and salicylaldehyde or o-hydroxylacetophenone, (3) one-pot "green" polymerization of diyne, disulfonyl azide, water and ethanol, (4) MCTP of alkyne, carbonyl chloride and ethyl 2-mercaptoacetate, (5) MCTPs of alkynes and carbonyl chloride with secondary amines, primary amines or chiral amino esters. These approaches are all featured with high efficiency, functional group tolerance, atom and step economy. Great endeavors have been devoted to the design of monomer and model compound structures, exploration of effective catalysts, optimization of polymerization conditions, structural characterizations of resultant polymers, and discovery of new phenomena, properties and applications. The polymeric materials with different architectures and functionalities are synthesized with high molecular weights (M
w up to 257100) in satisfactory isolation yields (up to 99%). The structures and properties of the polymers are carefully characterized and evaluated by standard spectroscopic techniques, such as IR, NMR, GPC, MS, TGA, UV, PL, CD and RI analyses. All the polymers possess good solubility, processability and thermal stability. Moreover, an array of novel functionalities have been discovered, such as novel aggregation-induced/enhanced emission characteristics, sensitive and selective chemosensors for metal ions, fluorescent patterning, high and tunable light refractivity, and so on. With the high efficiency in polymerizations and unique functionalities of the polymers, the polymerization concepts and approaches in the thesis work are believed to be effective and promising toward multifunctional polymeric materials by overcoming the drawbacks of conventional polymerizations.
| Date of Award | 2016 |
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| Original language | English |
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| Awarding Institution | - The Hong Kong University of Science and Technology
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