Synthesis of Functionalized 1-cyclooctyl-3-methyl-1,2,3-triazolium via click chemistry and their polymerization by ROMP

Abstract

This paper describes the synthesis of a new ionic liquid (IL) monomer of 5-substituted cyclooctene 1,2,3-triazolium iodides salt via click chemistry, and an anion exchange reaction with two different counteranions: bis(trifluoromethylsulfonyl)imide [N(SO₂CF₃)₂]⁻(NTf₂⁻), and hexafluorophosphate ([PF₆]⁻). The structural properties of all monomers were determined by MALDI-TOF-MS, (¹H; ¹³C; ¹⁹F;)NMR spectroscopy. 1,2,3-triazolium-based poly(ionic liquid)s (TPILs) with the pendant triazolium moieties were also synthesized by Ring-Opening Metathesis Polymerization (ROMP) using Grubbs second generation (Grubbs II) ruthenium as a catalyst with good control during the polymerization process and gave viscous solutions. The Synthesis of the polymers (TPILs) was confirmed by ¹HNMR spectroscopy. The thermal properties were characterized by thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The thermal stability of monomers was found to be high (∼286°C). Furthermore, monomers salts with [NTf₂⁻] have low melting points below 100°C (25-99°C), and their TPILs are viscous liquids at room temperature, with a low glass transition temperature (T_g = -23°C). This result suggests that the 5-substituted cyclooctene 1,2,3-triazolium ionic liquid monomer offers high chain flexibility to the resulting polymers (TPILs). Hence this new class of IL monomer and TPILs may be potentially useful in electrolyte membrane applications.