Simple and Effective Identification of Local 6 <i>π</i> ‐ and Global [4 <i>n</i>  + 2] Aromaticity of Macrocyclic Conjugated Hydrocarbons by ¹ H/ ¹³ C Chemical Shifts and the Corresponding Ring Current Effect

Structures, ¹H/¹³C chemical shifts, and the ring current effects (spatial magnetic properties: through-space NMR shieldings [TSNMRSs]) of various π-conjugated macrocyclic hydrocarbons and the corresponding charged analogues have been calculated at the B3LYP/6-311G(d,p) theory level using the GIAO perturbation method and employing the nucleus-independent chemical shift (NICS) characterization. The spatial magnetic properties (TSNMRS) are visualized as iso-chemical shielding surfaces (ICSSs) of various size and direction and together with especially the δ(¹H)/ppm chemical shifts employed to unequivocally qualify and quantify local 6π-aromaticity of individual benzenoid building blocks and the global ([4n + 2], n > 1) aromaticity of the macrocyclic ring.