| Summary: | Chapter 1: Introduction to Covalent Capture Purification and Ring-Opening Metathesis Polymerization In chemical spaces where difficult purifications are commonplace, innovative purification methodologies have been developed to circumvent the limitations associated with classical physiochemical property-driven purifications (chromatography, crystallization, distillation, etc.). Covalent capture purification—a type of catch-and-release purification—purifies molecules by selectively capturing them (via a covalent bond) onto a solid support, washing away impurities, and cleaving the product from the support for recovery. In the first half of this chapter, we review literature examples where covalent capture has been implemented for the purification of chemically synthesized molecules, including synthetic peptides, oligonucleotides, oligosaccharides, and small molecules. Ruthenium-initiated ring-opening metathesis polymerization (ROMP) remains an extraordinary tool for polymer synthesis due to its functional group tolerance, the ready availability of monomers and initiators, and the overall ease at which well-defined polymers can be rapidly synthesized. However, complete removal of ruthenium residues from the product is a difficult task that is compounded by the lack of understanding of initiator decomposition in ROMP. The existing methods for purification of ROMP polymers, which are typically solubility-based, are reviewed. The promise of covalent capture purification—a reactivity-based purification method— for living ROMP is discussed. Chapter 2: Covalent Capture Purification for Living Ring-Opening Metathesis Polymerization Covalent capture purification, a type of catch-and-release purification, facilitates complex molecule purification by partitioning reaction mixtures based on chemical reactivity rather than physiochemical properties. While this purification methodology has proven highly valuable for the purification of synthetic peptides, oligonucleotides, and oligosaccharides, it has not yet been implemented for the purification of synthetic polymers. Ruthenium-initiated living ROMP remains an extraordinary tool for polymer synthesis, but removal of trace ruthenium from the polymeric product remains a difficult task due to the wide scope of polymer compositions, the lack of a complete understanding of initiator decomposition, and the unknown identities of trace ruthenium products generated during ROMP. In this work, we translate covalent capture purification to living ROMP for the first time, and demonstrate its use as a general purification method for ROMP polymers. The optimized covalent capture system was used to purify a variety of linear polynorbornenes (up to ~7 kDa) in yields ≥49% and high purities (≥99.6% ruthenium removed). Chapter 3: Tricyclononenes and Tricyclononadienes as Efficient Monomers for ROMP: Understanding Structure–Propagation Rate Relationships and Enabling Facile Post-Polymerization Modification Tricyclononenes (TCN) and tricyclononadienes (TCND) represent under-explored classes of monomers for ROMP that have the potential to both advance fundamental knowledge (structure-polymerization kinetics relationships) and serve as practical tools for the polymer chemist (post-polymerization functionalization). In this work, a library of TCN and TCND imides, monoesters, and diesters, along with their exo-norbornene counterparts, were synthesized to compare their behavior in ruthenium-initiated ROMP. To understand the relationship between monomer structure and ROMP propagation rate, density functional theory methods were used to calculate a variety of electronic and steric parameters for the monomers. While electronic parameters (e.g., HOMO energy levels) correlated positively with the measured kp values, steric parameters generally gave improved correlations, which indicates that monomer size and shape are better predictors for kp than electronic parameters for this data set. Furthermore, the TCND diester— which contains an electron-deficient cyclobutene that is resistant to ROMP—and its polymer p(TCND) are shown to be highly reactive toward base-catalyzed conjugate addition with thiols, providing a protecting/activating-group free strategy for post-polymerization modification. Chapter 4: Safe and Scalable Syntheses of N,N-Dimethyltrifluoromethanesulfonamide (DMTMSA) and Other Trifluoromethanesulfonamide Solvents for High Energy Density Battery Applications A simple, scalable synthetic methodology for the synthesis of N,N-dimethyltrifluoromethanesulfonamide (DMTMSA) and other trifluoromethanesulfonamide solvents is described. No specialized glassware is required, water is the solvent, and an ice bath is used for cooling. Up to 155 g of DMTMSA is synthesized in a single batch in 92% yield. The optimized process is highly mass efficient (PMI = 9.1), and excess dimethylamine may be recovered (93% recovery, 51% decrease in waste) and recycled via a simple short-path distillation.
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