Struct. Chem. 28, 345-355 (2017)

DOI: 10.1007/s11224-016-0882-y

An insight on the aromatic changes in closed shell icosagen, tetrel, and pnictogen phenalenyl derivatives

A computational study of the aromatic and antiaromatic characteristics of closed shell charged phenalenyl (PLY+1 and PLY−1) upon replacement of the central carbon atom by icosagen (B, Al and Ga), tetrel (Si and Ge) and pnictogen (N, P and As) atoms comprising systems in which the icosagen and pnictogen derivatives considered are neutral while the tetrel ones are anions or cations, has been carried out at the B3LYP/6–311++G(d,p) computational level. By substitution, two different kinds of structures have been obtained, one planar (N and B) and another one bowl-shaped depending on the size of the central atom. In terms of aromaticity, the substitution of the central C atom causes a loss of the aromatic character in all cases as indicated by nucleus-independent chemical shifts (NICS) profiles and NICS values on the 0.001 au isosurface. Regarding the charge, PLY+1 presents larger electron delocalisation than PLY−1, phenomenon associated with aromaticity. Furthermore, the current density maps for those planar systems corroborate NICS findings, showing anticlockwise currents in PLY+1 (like in benzene) but clockwise in PLY-N0 and PLY-B0, indicating aromatic and antiaromatic behaviour, respectively.