Three-center two-electron bonds in the boranes B2H6 and B3H8− from the quantum interference perspective

Abstract

In this work the nature of the three-center two-electron (3c2e) chemical bonds in the diborane (6) molecule and the octahydrotriborate anion (B3H8−) is investigated by the Generalized Product Function Energy Partitioning (GPF-EP) method using modern valence bond wave functions. The Interference Energy Analysis shows that 3c2e bonds have the same features of a 2c2e bond: interference dominates the energetic balance for the formation of the bond and the kinetic energy drop is responsible for its stabilization. Also, 3c2e are generally way more energetic than a 2c2e analogous one, because interference can occur in three different ways (multiple interference effect), rather than just in one as for the two-center bonds. Furthermore, with the GPF-EP method one could establish a more rigorous way for discussing the idea of a “supported” bond in the diborane (6) molecule.