NMR studies of ionic liquids: Structure and dynamics

• NMR provides a plethora of tools for studying the structure and dynamics of ionic liquids.
• 1H chemical shifts and intermolecular NOE factors elucidate hydrogen-bonded cation–anion pairing.
• Pulsed field gradient spin echo techniques characterize the self-diffusion of the ions.
• Multinuclear magnetic relaxation times elucidate the rotational dynamics of the ions.

The past two decades have seen the advent of a new class of solvents with unique properties, referred to as “Ionic Liquids”. This term describes low-melting organic salts, which open a window for chemical processes in ionic environments near room temperature. A molecular-based understanding of their properties is crucial for a rational design for applications. An important prerequisite is the characterization and understanding of their structure and dynamics. Application of NMR techniques to characterize ionic liquids has rendered many unique and valuable insights on these subjects. Here, recent highlights and typical applications are elucidated along with the advantages and limitations of the various techniques.

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