Computational Study of sp x ( x =1–3)‐Hybridized Be−Be Bonds Stabilized by Amidinate Ligands

Complexes containing odd‐electron Be−Be bonds are still rare until now. Hereby, a series of neutral di‐beryllium amidinate complexes containing a Be−Be bond were explored theoretically. The complexes with direct chelation with the Be 2 dimer by the bidentate amidinate (AMD) ligands are always corresponding to their global minimum structures. The detailed bonding analyses reveal that the localized electrons of the Be−Be fragment can be adjusted by the amount of AMD ligands because each AMD ligand only takes one electron from the Be 2 fragment. Meanwhile, the hybridization of the central Be atom also changes as the number of AMD ligands increases. In particular, the sp 3 ‐hybridized single‐electron Be−Be bond is firstly identified in the tri‐AMD‐ligands‐chelated neutral D 3 h ‐ Be 2 (AMD) 3 complex, which also possesses the higher stability compared to its monoanionic D 3 h ‐ Be 2 (AMD) 3 − and monocationic C 3 ‐ Be 2 (AMD) 3 + analogues. Importantly, our study provides a new approach to obtain a neutral odd‐electron Be−Be bond, namely by the use of radical ligands through side‐on chelation.