HOMA parameters for the boron–boron bond: How the introduction of a BB bond influences the aromaticity of selected hydrocarbons

An extension of the harmonic oscillator model of aromaticity (HOMA) model for systems with boron–boron bonds is presented. For the first time, the parameters of the HOMA model are estimated using only theoretically calculated bond lengths. The HOMA parameters obtained make geometric aromaticity studies possible for a large number of compounds containing the boron–boron bond. The derived HOMA parameters have been used to investigate how the introduction of the boron–boron moiety in the structure of selected hydrocarbons modifies their aromaticity. The conclusion is that the insertion of a boron–boron bond usually strongly decreases the aromaticity of the boron-containing compounds in comparison to their parent hydrocarbons.