Can external electric field influence the B–Hb⋯π interaction? a computational insight

A computational study was performed for scrutinizing the effect of positively and negatively directed external electric field (EEF, within the range of −0.0200 to +0.0200 a.u.) on the B–H_b⋯π interaction of diborane (Db) with benzene, borazine, pyridine, pyrrole, furan, thiophene, cyclopentadienyl anion, pentazolate anion, ethene, ethyne, cyclobutadiene and oxygen for the first time. The MP2/cc-pVTZ level of theory was used for all calculations. Apart from B–H_b⋯π interaction, variations in molecular electrostatic potential (MEP), HOMO energy, charge transfer (Δq), global hardness (η), electrophilicity (ω), chemical potential (μ) and dipole moment were analysed in the presence of EEF. The strength of B–H_b⋯π interactions in Db-Ben, Db-Py, Db-Pyr, Db-Fur, Db-Eth, Db-Ethy, Db-CBD and Db-Oxy complexes increased in the presence of EEF along the positive x-direction and was more than doubled (from 1.26 to 5.34 kcal mol⁻¹, up to 166%) at +0.0200 a.u. EEF. However, the stability of Db-Bora, Db-Thio, Db-Cp⁻ and Db-Pnz⁻ complexes increased in the presence of EEF along the negative x-direction and was more than doubled (from 2.73 to 18.10 kcal mol⁻¹, up to 134%) at −0.0200 a.u. HOMO energy, charge transfer, global hardness, electrophilicity, chemical potential and dipole moment also varied in the presence of an EEF and were found to be magnitude and direction sensitive, especially along the x-direction.