| Quantum chemical calculations have been performed to study the interaction nature of complexes formed by MgX2?X = H,F?molecule with acetylene,ethylene,and benzene,respectively.Results indicate that the nonbonded interactions,namely ?-magnesium bonds,contribute to the stability of the resulting dimers.Intriguing structural evolution has been found for these complexes with different ? electron donors getting involved.Upon complexation,both Mg-X and C–C bonds lengthened,accompanied by redshifted X-Mg-X and C–C stretching vibrations.NBO analysis reveals that the main charge-transfer from the conjugated molecules to MgX2 is from the ?CC bonding orbital to the empty lone pair orbital of Mg.Energy decomposition analysis indicates that the stability of the topic complexes mainly comes from the attractive electrostatic interaction and polarization,similar to the case of ?-beryllium bonds.When compared with other nonbonded interactions,it is found that ?-magnesium bonds are stronger than ?-lithium and ?-sodium bonds.Especially,they are comparable in strength to ?-beryllium bonds with Mg F2 playing the role of Lewis acid. |
PDF Full Text Request