Suitability of Carbazolyl Hauser and Turbo‐Hauser Bases as Magnesium‐Based Electrolytes

Abstract Lithium‐ion batteries pose certain drawbacks and alternatives are highly demanded. Requirements such as low corrosiveness, electrochemical stability and suitable electrolytes can be met by magnesium‐ion batteries. Metalation of carbazole with Mg in THF in the presence of ethyl bromide yields the sparingly soluble Hauser base [(thf) 3 Mg(Carb)Br] ( 1 ) which shows a Schlenk‐type equilibrium with formation of [(thf) 3 Mg(Carb) 2 ] and [(thf) 4 MgBr 2 ]. A THF solution of 1 shows a low over‐potential and a good cyclability of electrodeposition/‐stripping of Mg on a Cu current collector. An improved performance is achieved with the turbo‐Hauser bases [(thf)(Carb)Mg(μ‐Br/X) 2 Li(thf) 2 ] (X=Br ( 2 ) and Cl ( 3 )) which show a significantly higher solubility in ethereal solvents. The THF solvation energies increase from (thf) x MgBr 2 over (thf) x Mg(Carb)Br to (thf) x Mg(Carb) 2 for an equal number x of ligated THF molecules.