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. ***
