Structural Studies of Lithium 4,5-Dicyanoimidazolate–Glyme Solvates. 1. From Isolated Free Ions to Conductive Aggregated Systems

We present complementary series of
crystal structures of lithium
salts containing 4,5-dicyanoimidazolato anions substituted with perfluoroalkyl
groups. Single-crystal X-ray analysis of 10 adducts with aprotic solvents,
glymes (dimethyl ethers of poly­(ethylene glycols)) and crown ethers,
have been performed to correlate their molecular structures and properties
with spectroscopic and thermal data. Comprehensive structure analysis
of crystalline materials reveals valuable information about the coordination
ability of substituted 4,5-dicyanoimidazolato anions and provides
the basis for developing the model of poly­(ethylene oxide) electrolytes
and liquid systems. Presented results reveal new aggregation modes
at high concentrations of lithium salts involving the release of cations
by self-assembly of an anionic subnetwork and provide some insight
into the electrochemical performance of TDI anions.