The first magnesium-based electride was synthesized by researchers in Norway, Poland and Spain. Electrodes are of interest to materials scientists because they contain electrons floating in internal cavities and therefore exhibit properties such as high conductivity. Among other things, this new species is stable at room temperature, offering new opportunities in materials science and catalysis.1
Thanks to their floating electrons, electrides have found applications in superconductors, optical materials, electronic devices and magnets.2 These free electrons also confer interesting properties for catalysis, in particular in oxidation-reduction reactions such as the formation of ammonia from nitrogen and the upgrading of carbon dioxide. However, most of these species are complex inorganic mixtures. So far, eight organic electrides have been synthesized, and this magnesium-based example marks only the second species stable at room temperature.
Additionally, magnesium electride is easily prepared from an abundant nickel-dipyridine complex in a single step with excellent yields. The reaction leads to a tetranuclear magnesium compound, which holds a single electron in the cubic cavity formed by the metal atoms. Contrary to other examples, in this case the electron is not delocalized on different cavities.
The researchers also tested the versatility of the new magnesium electride as a reducing agent. They attempted the synthesis of some low-valence nickel complexes, which usually require the use of pure lithium and suffer from undesirable side reactions. The reaction was faster and cleaner, demonstrating the potential of this magnesium electride in homogeneous catalysis. Additionally, magnesium species is highly soluble in organic solvents and easily stored in a glove box, suggesting promising possibilities in other reduction reactions.