Hydrophobic n-Alkyl-N-isoquinolinium Salts: Ionic Liquids and Low Melting Solids

A series of hydrophobic n-alkyl-N-isoquinolinium ionic liquids (ILs) with a linear alkyl-chain substituent containing from 4-18 carbon atoms in combination with hexafluorophosphate, bis(trifluoromethylsulfonyl)amide, and bis-(perfluoroethylsulfonyl)amide have been synthesized and characterized (water content, density, DSC, TGA, and LSER). The crystal structures of [C 2 isoq][PF 6 ] (prepared and isolated only for the comparative X-ray diffraction study), [C 4 isoq]-[PF 6 ], and [C 10 isoq] [PF 6 ] illustrate the underlying interactions in the higher melting salts. The isoquinolinium-based ILs studied here are interesting due to their highly aromatic nature and physical and solvent properties.