Evaluation of NICSzz Isosurfaces
A three-dimensional analysis to assess the anisotropic effects of NICSzz was carried out, providing more insights regarding the (anti)aromaticity of the BxNx clusters. NICSzzisosurfaces are depicted in Fig. 4. The presence of long-range diatropic regions inside the rings are indicative of their aromatic character. This can be observed in B3N3 where diatropic zones are located at the center and, additionally, located in nitrogen atoms due to the contributions of core electrons. The opposite effect can be seen B2N2, B4N4 and B6N6, where strong paratropic long-range zones are located at the center of these rings, denoting their antiaromatic character. Along with this, the diatropic zones located in the nitrogen atoms are also observed.
In B5N5, diatropic zones in nitrogen atoms and above the molecular ring are observed, however it is possible to see paratropic values at the centre of the ring, this characteristic pattern has been observed in non-aromatic organic systems including cyclopropane and cyclohexane58. The rest of the systems present diatropic regions located in the nitrogen atoms and short range paratropic zones in the center of the ring, characteristic of its non-aromatic nature.