Ino-Chloridolithates from Ionothermal Synthesis

Abstract

Anionic lithium-containing species were predicted to impact ionic liquid-based electrochemical applications but have hitherto never been isolated from ionic liquid systems. Here, we report the first representatives of this class of compounds, inochloridolithates, comprising [LiCl 2 ] − and [Li 2 Cl 3 ] − polyanions from ionothermal reactions. Such compounds are obtained at moderate temperatures with imidazolium-based ionic liquids and LiCl. The addition of an auxiliary ammonium salt enhances the lattice energy to yield an ammonium lithate in good yields, which enables extensive investigations including solid-state nuclear magnetic resonance, infrared, and Raman spectroscopy. The structural motifs of inolithates are related to ino-silicates, as 1D-extended anionic substructures are formed. Despite this analogy, according to density functional theory calculations with periodic boundary conditions, no evidence of covalent bonding in the anionic moieties is found−indicating packing effects to be the main cause for the formation. Based on an in-depth analysis of the different synthetic parameters, this class of compounds is discussed as an intermediate in ionic liquid applications and could serve as a model system for electrochemical lithium-based systems.