Supramolecular Chemistry with Macromolecules

高分子超分子化学

• 批准号: 9706909
• 负责人: Harry Gibson
• 金额: $ 31.5万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-15 至 2001-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706909&HistoricalAwards=false
• 关键词: Supramolecular; Chemistry; Macromolecules

9706909 Gibson A roxatane consists of a cyclic molecule physically threaded onto a linear molecule with no covalent bonds between the cyclic and the linear species; a catenane consists of interlocked cyclic molecules. The concepts of supramolecular chemistry will be employed to synthesize new polymeric roxatanes and catenanes. Microcalorimetry will provide fundamental data on the threading of cyclic molecules by linear species with respect to factors such as the nature of the two components (size, rigidity, structure), the solvent and temperature. Building on this thermodynamic data base for small molecules, these building blocks will be used to produce new polymeric materials. Three prototypical supramolecular systems that possess high association constants will be utilized to construct entirely new polyrotaxanes, including main chain and graft systems. A new class of hyperbranched and dendritic macromolecules whose structural integrity is based on rotaxane repeat units will be synthesized from psuedorotaxanes (without stoppers) having AB2 functionalities; the repeat units will consist of a linear species with macrocyclic end groups, the linear portion being threaded through the macrocycle of another unit. Another new class of macromolecules, slip link polymers, consisting of a rotaxane repeat unit in a linear structure will be prepared by polymerization of standard BB monomers with novel pseudorotaxane, AA topological monomers in which one functionality resides on the linear guest portion and one on the cyclic or host portion and the linear portion bears a bulky blocking group; such materials are expected to show novel behavior under longitudinal tension and compression because of the compliance of the rotaxane structure. Since the complexation processes can reversed under suitable conditions the properties (light absorption, viscosity, solid state structure, solubility, mechanical properties, etc.) of these systems are expected to be sensitive the thei r environments, e.g., temperature, solvent, redox conditions, the presence or absence of metal ions or the acidity of the medium. Finally the oldest method of rotaxane and catenane formation, the so-called chemical conversion method, will be applied for the first time to prepare polyrotaxanes and polycatenanes. This method involves reaction of molecules that possess linear components threaded intramolecularly through a macrocycle attached via a "temporary bond". Polymerization via terminal functionalities on the linear thread will yield polyrotaxanes after the temporary bond is broken. On the other hand, cyclization of the self threaded system will be employed to make a series of functionalized 2 catenanes of the AA, AB, and AB2 types, which will be polymerized to form a variety of new linear, hyperbranched and dendritic poly 2 catenanes. %%% The principles of supramolecular chemistry will be applied to the construction of several new families of polymeric materials which contain units that are mechanically rather than chemically linked together. Because of their novel topological structures the physical properties of these new materials are expected to be unusually responsive to their environments and external stimuli. Thus these systems offer entirely new design principles for controlling physical and chemical properties that could enable new sensors, smart or adaptable materials and electronic devices. ***

9706909吉布森罗沙坦由物理地连接到直链分子上的环状分子组成，在环状和直链物质之间没有共价键;索烃由互锁的环状分子组成。 超分子化学的概念将被用来合成新的聚合物氧杂环丁烷和索烃。 微量热法将提供关于线性物质对环状分子的螺纹的基本数据，这些因素包括两种组分的性质（尺寸、刚度、结构）、溶剂和温度。 基于小分子的热力学数据库，这些构建模块将用于生产新的聚合物材料。 三个具有高缔合常数的典型超分子体系将被用来构建全新的聚轮烷，包括主链和接枝体系。 一类新的超支化和树枝状的大分子，其结构完整性是基于轮烷重复单元将合成从psuedorotaxane（没有终止子）具有AB 2功能;重复单元将由一个线性的物种与大环端基，线性部分被线程通过另一个单元的大环。 另一类新的大分子，滑动连接聚合物，由线性结构中的轮烷重复单元组成，将通过标准BB单体与新的准轮烷AA拓扑单体的聚合来制备，其中一个官能团位于线性客体部分上，一个官能团位于环状或主体部分上，并且线性部分带有庞大的封端基团;由于轮烷结构的柔顺性，预期这种材料在纵向拉伸和压缩下表现出新颖的性能。 由于络合过程可以在合适的条件下逆转，因此性质（光吸收、粘度、固态结构、溶解度、机械性质等）可以在适当的条件下改变。预期这些系统中的每一个对它们的环境敏感，例如，温度、溶剂、氧化还原条件、金属离子的存在或不存在或介质的酸度。 最后，最古老的轮烷和链烷形成方法，所谓的化学转化法，将首次应用于制备聚轮烷和聚链烷。 该方法涉及具有线性组分的分子的反应，所述线性组分在分子内穿过经由“临时键”连接的大环。 通过线性线上的末端官能团的聚合将在临时键断裂后产生聚轮烷。 另一方面，将采用自螺纹体系的环化来制备AA、AB和AB 2型的一系列官能化2索烃，其将聚合以形成各种新的线性、超支化和树枝状聚2索烃。 超分子化学的原理将被应用于几个新的聚合物材料家族的建设，其中包含的单位是机械连接在一起，而不是化学连接在一起。 由于其新颖的拓扑结构，这些新材料的物理性质预计将对其环境和外部刺激做出异常响应。 因此，这些系统提供了全新的设计原理，用于控制物理和化学性质，从而可以实现新的传感器，智能或适应性强的材料和电子设备。 ***