Ionic Liquids and Ionothermal Synthesis

Ionic Liquids: Designing Liquids with Innovative Properties – From Fundamentals to Applications

Ionic liquids represent an exciting frontier for inorganic and materials chemists, offering a treasure trove of unique and intriguing possibilities. For instance, metal-containing ionic liquids are emerging as promising new materials. They combine the distinctive properties of ionic liquids with the added benefits of intrinsic magnetic, catalytic, or spectroscopic characteristics, dependent on the specific metal ion incorporated.

Functionalized ionic liquids have demonstrated their potential as versatile reaction media. They facilitate the synthesis of inorganic compounds with unprecedented properties and can also be used for the creation of coordination polymers. Moreover, they have proven to be invaluable for the crystallization and crystal engineering of novel coordination compounds.

These novel liquids are more than just a fascinating subject of academic study. They hold the potential to revolutionize a wide range of practical applications, from energy storage and green chemistry to advanced material synthesis and beyond. Our research in this field is driven by an interest to understand their properties at a fundamental level, and to translate this knowledge into practical applications that can drive forward the frontiers of inorganic and materials chemistry.

Ionothermal Synthesis: Creation of Advanced Functional Materials and Nanomaterials

As we delve deeper into the world of ionic liquids, they are rapidly expanding beyond conventional expectations into areas such as materials chemistry and crystal engineering. The crystallization strategies offered by ionic liquids are distinctively different from those involving traditional organic solvents. Rather than just replacing conventional solvents, ionic liquids have the unique ability to function as neutral solvents, templates, reactants, or even charge compensating species. This versatility opens up new synthetic and crystallization pathways, akin to solid-state synthesis using a salt as a flux.

However, ionothermal synthesis, as this process is known, operates at significantly lower temperatures, ranging from room temperature to approximately 500 K. This offers new possibilities for a “gentle” solid-state synthesis of inorganic compounds. It allows for the formation of compounds with uncommon coordination modes, low oxidation states, or the stabilization of metastable compounds.

A major challenge in the synthesis of semiconductor nanocrystals, suitable for solar energy conversion, is controlling their composition and morphology. Ionic liquids, with their ability to dissolve most semiconductor precursors, including elemental chalcogenides, have emerged as a potent solution. They can actively participate in the capping and structuring during nanoparticle growth and can withstand high temperatures without degradation.

  1. Tyrrell; G. Behrendt; P. Nockemann: ‘Ionothermal Syntheses of Nano- and Microstructured Ternary Copper-Indium-Chalcogenides.’ Inorganic Chemistry, 2015, 54, 4495-4503.
  2. Tyrrell; M. Swadzba-Kwasny; P. Nockemann: ‘Ionothermal, microwave-assisted synthesis of indium(III) selenide.’ Journal of Materials Chemistry A, 2014, 2, 2616-2622.
  3. Swadzba-Kwasny; L. Chancelier; S. Ng; H. G. Manyar; C. Hardacre; P. Nockemann: ‘Facile in situ synthesis of nanofluids based on ionic liquids and copper oxide clusters and nanoparticles.’ Dalton Trans. 2012,41, 219-227.
  4. Nockemann; B. Thijs; K. Van Hecke; L. Van Meervelt; K. Binnemans: ‘Polynuclear metal complexes obtained from the task-specific ionic liquid betainium bistriflimide.’ Crystal Growth & Design, 2008, 8, 1353-1363.
  5. J. Osborne; S. Wellens; C. Ward; S. Felton; R. M. Bowman; K. Binnemans; M. Swadzba-Kwasny; H. Q. N. Gunaratne; P. Nockemann: Thermochromism and switchable paramagnetism of cobalt(II) in thiocyanate ionic liquids.Dalton Trans., 2015, 44, 11286-11289.
  6. Nockemann; M. Pellens; K. Van Hecke; L. Van Meervelt; J. Wouters; B. Thijs; E. Vanecht; T. N. Parac-Vogt; H. Mehdi; S. Schaltin; J. Fransaer; S. Zahn; B. Kirchner; K. Binnemans: Cobalt(II) Complexes of Nitrile-Functionalized Ionic Liquids.Chemistry-a European Journal, 2010, 16, 1849-1858.
  7. Nockemann; B. Thijs; N. Postelmans; K. Van Hecke; L. Van Meervelt; K. Binnemans: Anionic rare-earth thiocyanate complexes as building blocks for low-melting metal-containing ionic liquids.Journal of the American Chemical Society, 2006, 128, 13658-13659.