B₃H₃Be ← F^-: A Case of Extremely Strong Dative Bond

Chemical bonding has attracted chemists since its inception. Dative bonding between a donor and acceptor moiety is also an important phenomenon, which results in stabilization of many chemical compounds. Herein, we show that an extremely strong dative bond is possible between a fluoride ion and a beryllium center which is a part of a half-sandwich complex, B₃H₃Be. Quantum chemical calculations have shown the possibility of formation of a half-sandwich complex of Be with a B₃H₃^2- ring. Calculations reveal that the complex is stable toward dissociation. The half-sandwich complex features a very low-lying lowest unoccupied molecular orbital (LUMO) concentrated on the Be atom, thereby indicating a Lewis acidic character of the complex. This lower-lying LUMO at the beryllium center is responsible for forming an extremely strong dative bond with the fluoride donor.