The aromaticity of boron-nitrogen clusters has been revisited through a
systematic analysis using magnetic criteria. The results obtained
through Ring Current Strength (RCS) measurements indicate that
B2N2 has a strongly antiaromatic
character, even the bond pattern analysis reveals that this system is
doubly antiaromatic presenting two σ- and two π-orbitals of 4c-2e,
according to the Adaptive Natural Density Partitioning bond pattern
analysis (AdNDP) and z-component of the dissected Nucleus Independent
Chemical Shift (NICSzz) isolines.
B6N6 are marginally antiaromatic
according to RCS and the bond pattern suggest four and six 8c-2e and
12c-2e delocalized π-orbitals respectively.
B5N5 are slightly aromatic, with a bond
pattern of three and five 6c-2e and 10c-2e π-orbitals respectively. All
rest of the systems (x = 7 – 11) are non-aromatic. The results show
some discrepancies with results based on the classical nucleus
independent chemical shift, which can be attributed to tensor in-plane
and core electron contributions. Finally, presented results reveal the
need to be careful with the interpretations given by this index, so it
will be necessary the use of 1D, 2D or 3D derived methodologies for a
complete and correct analysis of (anti)aromaticity.