Magnetic Ionic Liquids : a molecular pathway to liquid magnets

The wide variety of magnetic materials and their fields of application make them the source of significant industrial and economic activity. In 2015, this was estimated at over 83 billion euros by 2020. The most important fields of application are power generation and distribution, including new energy sources such as wind power. In addition, the recent revolution in nanoscience and nanotechnology has promoted original magnetic properties observed in nanoscale materials, such as giant magnetoresistance and the birth of spin electronics, which have revolutionized magnetic recording (Albert Fert and Peter Grünberg, Nobel Prize 2007). Although most fields of application rely on the use of solid materials, such as transition and rare-earth metals and their alloys, and oxide ceramics, the preparation of fluid solutions of paramagnetic complexes or suspensions of superparamagnetic nanoparticles offers a good compromise between physical form and magnetic behavior in certain cases. In an alternative approach, the chemistry of molecular nano-magnets, crossed with the chemistry of ionic liquids, provides a route to pure, liquid molecular magnetic materials. The possibilities offered by synthetic molecular chemistry also make it possible to modulate parameters that are essential for applications, such as the range of use with melting point engineering.

This article presents the state of the art for such magnetic ionic liquids. After a brief overview of molecular magnetic materials, the synthesis methods, physicochemical properties and present and future applications of magnetic ionic liquids are described.

At the end of the article, readers will find a glossary and table of acronyms and symbols.