Imidazolium‐Based Zwitterionic Butane‐1‐sulfonates: Synthesis and Properties of 4‐(1‐(2‐Cyanoethyl)imidazolium)butane‐1‐sulfonate and Crystal Structures of 4‐(1‐Alkylimidazolium)butane‐1‐sulfonates (Alkyl = Methyl, Ethyl, Propyl)

The reaction of 1‐alkylimidazoles (alkyl = methyl, ethyl, propyl, 2‐cyanoethyl) with 1,4‐butane sultone in equimolar stoichiometry resulted in the formation of 4‐(1‐methylimidazolium)butane‐1‐sulfonate SBMIm , 4‐(1‐ethylimidazolium)butane‐1‐sulfonate SBEIm , 4‐(1‐propylimidazolium)butane‐1‐sulfonate SBPIm , and 4‐(1‐(2‐cyanoethyl)imidazolium)butane‐1‐sulfonate SBCNEtIm , respectively, in high yields. Properties of these four imidazolium‐based zwitterionic compounds were investigated with respect to question of their use as suitable precursors for Ionic Liquids. The structures of the compounds SBMIm , SBEIm , and SBPIm were determined by single‐crystal X‐ray diffraction. SBMIm and SBEIm crystallize both in the triclinic space group P $\bar{1}$ , SBMIm : a = 8.4454(6), b = 8.4492(6), c = 8.7532(7) Å, α = 66.610(2), β = 66.235(2), γ = 70.625(2)°, Z = 2, R 1( F )/ wR 2( F 2 ) = 0.0279/0.0832; SBEIm : a = 8.4359(2), b = 8.5900(2), c = 8.6790(2) Å, α = 73.487(2), β = 71.228(1), γ = 70.979(2)°, Z = 2, R 1( F )/ wR 2( F 2 ) = 0.0333/0.0820; SBPIm with monoclinic symmetry, space group P 2 1 / c : Z = 4; a = 7.2979(3), b = 17.5312(8), c = 9.5682(4) Å, β = 90.922(3)°, R 1( F )/ wR 2( F 2 ) = 0.0507/0.1198.