In silico study of strong beryllium–boron bonds in (BeF–E3B)− (E = P, as) adducts

The potential for the development of a strong interaction between the Be and B atoms in (P 3 B–BeF) − and (As 3 B–BeF) − adducts was evaluated using gas phase quantum chemical calculations at the M06–2×/def2-TZVP level. The Be B bond dissociation energies of the investigated compounds are higher than that of the [BH 3 –BeF] − adduct. This is because the Lewis acidic character of the neutral P 3 B/As 3 B unit is greatly enhanced by the pyramidal shape of the B centre. NBO analyses, QTAIM, and ELF study confirm that the Be B bond in both the adducts is of polar covalent nature. The strong covalent bond formation in the adducts is further supported by ETS-NOCV analysis.