Thermochemical and Structural Studies of New Chiral and Achiral Long Alkyl Chain Functionalized Imidazolinium Ionic Liquids

Abstract

Adding to the versatile class of ionic liquids (ILs), an entirely new series of imidazolinium-based ionic liquids is reported herein, offering chirality and important thermal characteristics, such as polymorphism, glass transition, and plastic crystalline behavior. An efficient and general procedure for the preparation of long N,N′-alkyl chain-substituted compounds with either saturated (s) or chiral (c) cyclohexyl (cyC6)-substituted imidazolium (Im) backbones, namely, [C12C12RsIm]­[A] (A = Br–, [BF4]−, [ClO4]−, [PF6]−; R = H, Me, i Pr) and [C12C12cIm-cyC6]­[A] (A = Br–, I–, [I3]−, [BF4]−, [ClO4]−, [PF6]−, [SbF6]−, [BPh4]−), was developed, and the novel compounds were studied by thermochemical methods (DSC, TGA), X-ray diffraction in the small angle regime (SAXS), single-crystal X-ray diffraction (SC-XRD), and specific rotation analysis.