Synthesis of polyrotaxanes

• Grant number: 22/04644-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2022
• End date: July 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Jackson Dirceu Megiatto Junior
• Grantee: Liniquer André Fontana
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 21/06605-8 - Systems chemistry: controlling the complex behavior of mixtures of interacting molecules to develop molecular machines, interlocked polymers and new materials, AP.JP2

Abstract

This project describes a new synthetic strategy based on the active metal template synthesis for the preparation of polyrotaxanes. Using the endotopic properties of Ru(II)porphyrinate-based macrocycles, the project describes the assembly of polyrotaxanes from monomers containing tosylhydrazone groups and functionalized with terminal diazoacetate and thiol groups. S-H carbene insertions promoted by the Ru(II) porphyrinate-based macrocycles will lead to formation of polyrotaxanes containing bulky tosylhydrazone groups along the molecular thread. These tosylhydrazone groups function as stoppers and will not allow the macrocycles to move along the polymeric thread. Therefore, we expect polyrotaxanes with well-defined structures, with high molar mass and low polydispersity. In a second step, the tosylhydrazone groups will be transformed into diazo groups to react with the Ru(II) ions in the polyrotaxanes macrocycles to generate carbenes along the polymer thread. The molecular design of the polyrotaxanes was conceived so that these carbenes will insert into C-H benzyl bonds present on the thread itself to generate benzofuran groups, which are not bulky and allow the macrocycles to move along the thread freely. Thus, the project proposes formation of polymers containing only mechanical bonds. The project also describes some spectroscopic and chromatographic techniques for the structural characterization of polyrotaxanes. (AU)