Activation of dihydrogen by group‐14 substituted germylenes

Abstract

We have investigated the structural and thermodynamic parameters of group‐14 substituted germylenes and their reactivity toward the H2 molecule using density functional theory (DFT). We conducted the detailed Kohn–Sham molecular orbital (KS‐MO) analysis to quantify the effective factors behind the increased reactivity of germylenes in going from C to Sn as substituents. The quantum theory of atoms in molecules (QTAIM), non‐covalent interaction (NCI), and natural bond orbital (NBO) analyses revealed the nature of bonds and interactions and demonstrated the reactivity trend of germylenes in the presence of H2. The results showed that in going from C to Sn, the reactivity increased due to an improvement in ‐donation interaction between the filled lone‐pair orbital of the germylene (LPGe) and the *‐orbital of H2, which decreased the reaction barrier (E‡). As the germylene substitution was varied from C to Sn, a significant reactivity was observed for the germylene toward the H2. This observation was caused by a reduction in steric repulsion between the germylene and the H2 and less activation energy due to the higher ‐donation and lower back‐donation. We have presented the reactivity of new and rationally designed germylenes toward H2 using various analyses that will serve as a guide for the activation of small molecules such as H2, which is employed in many subsequent reactions.