Syntheses of the first N-mono- and N, N′-dipolyfluoroalkyl-4,4′-bipyridinium compounds

Abstract

Reactions of 4,4′-bipyridine (1) with excess of polyfluoroalkyl iodides (2a–d) at 100–110 °C, under neat conditions, led to the formation of monoquaternary salts (3a–d) in >90% yields. Salts 3a–d were metathesized with LiN(SO₂CF₃)₂ either in water or water/acetone mixtures to form ionic liquids (4a–d), respectively, in >88% yields. When 1 was reacted with 2.5 equivalent of 2a–c in DMF at 110 °C, the diquaternary salts 5a–c were formed in >85% yields. Alternatively, 5a–c were also synthesized by heating a mixture of 3a–c and 2a–c (1.25 equivalent) in DMF. The metathesis reaction of 5a–c with LiN(SO₂CF₃)₂ produced dicationic ionic liquids (6a–c) in >86% yield.