A Complex Containing Four Magnesium Atoms and Two Mg–Mg Bonds Behaving as an Electride

Abstract

Herein, we report for the first time the stabilization of two Mg(I)–Mg(I) bonds simultaneously in the same complex. The β-diketeminate based ligand is modified computationally and a new class of ligand, DippHL (Dipp = 2,6-diisopropylphenyl) is designed that can hold two Mg atoms. Two such ligands stabilize two Mg22+ ions in a planar configuration and [Mg4(DippHL)2]2– complex is formed. Formation of a synthetically viable neutral [Mg4(DippHL)2]2–·2[K@CE]+ (CE = 18-crown-6 ether) complex is possible with the reduction of a proper precursor-like [Mg2(DippHL)I2]– with potassium metals in toluene solvent and the reaction is exothermic in nature. The computed Mg–Mg bond lengths are in close agreement with that of the Mg–Mg single bond. The results obtained from natural bond orbital (NBO) and atoms in molecule (AIM) analyses confirm the presence of two Mg–Mg bonds in the complex. The complex under study has fulfilled all of the desired criteria and proved itself to be termed as an electride.