Introduction of versatile and recyclable network poly (ionic liquid)s as an efficient solvent with desired properties for application in C-C cross-coupling reactions

Abstract

Synthesis of high viscosity, ecofriendly, and low melting point poly(ionic liquid)s (LMP-PIL) with network structure has been introduced by the reaction of TAIm[I] ionic liquid monomer with disodium salts of various open-chain carboxylic acids as well as sulfonic acids via a polycondensation on counter ions (PC-CI). Changes in methylene group numbers of carboxylate, as well as sulfonate, provide a broad spectrum of properties in terms of viscosity, density, and solubility for the resulting PILs. The physical properties of the PILs including, viscosity, melting point, boiling point, density, M¯n , and DPI, were determined in this study. The ecofriendly PILs served as an efficient solvent and ligand for the Cu-catalyzed Heck and Sonogashira C-C coupling reactions. High to excellent yields were obtained for various coupling products under mild conditions at MP of the PILs. The prepared PILs could be recycled several times from the homogenous reaction mixture with preservation of the intrinsic properties. Also, a deep study was conducted on the mechanism of the coupling reactions.