Theoretical investigation of triple bond in molybdenum complexes trans-[X(PMe3)4MoE(Mes)] (XÂ =Â F, Cl, Br, I; EÂ =Â Si, Ge, Sn, Pb): A DFT study

► Calculated MoE bond distances are significantly short. ► Significant electronic charge transferred in the direction [X(PMe3)4Mo]− → [E(Mes)]+. ► The MoE bond strength vary as E = Si > Ge > Sn > Pb and X = F > Cl > Br > I. ► The Mo ← E σ-donation is much smaller than the Mo → E π-back donation. ► The out-of-plane π-bonding is greater than the in-plane π-bonding.