On single-electron magnesium bonding formation and the effect of methyl substitution

The complexes formed between MgX(2) (X = F, H) molecules and alkyl radicals Y [Y = CH(3), CH(2)CH(3), CH(CH(3))(2), and C(CH(3))(3)] have been characterized by using quantum chemical methods. The binding distance in all cases is less than the sum of vdW radii of Mg and C, indicating the formation of a non-covalent interaction, namely single-electron magnesium bond. Energy decomposition analysis reveals that electrostatic and polarization contributions are the major components responsible for the stability of the studied complexes. According to interaction energy, atoms in molecules, and independent gradient model analyses, methyl substitution on electron donor Y imposes a positive effect on its complexation with MgX(2). When compared with other nonbonded interactions, the single-electron magnesium bond is found to have strength comparable to those of the single-electron beryllium bond and π-magnesium bond.