We consider all systems that presumably contain concentric ring currents, the dicationic substituted benzenes with formula C 6R 6 2+ (R=I, At, SeH, SeCH 3, TeH, TeCH 3). These findings motivated us to examine the putative concentric σ‐ and π‐delocalization in substituted benzene dications through the analysis of the induced magnetic field ( B ind) 20, 21 and its orbital contributions, 22 in order to provide a more detailed description of the electron delocalization and the role played by σ‐ and π‐electrons. 19 These authors also determined, via X‐ray diffraction, that the C−C bond lengths of the internal C 6‐ring are practically identical to benzene. More recently, Furukawa and coworkers studied the hexakis(phenylselenyl)benzene dication aromaticity. 11 Their GIMIC 16, 17, 18 calculations confirmed the existence of two concentric clockwise (diatropic) ring currents in C 6I 6 2+ and C 6At 6 2+, although the external current density is approximately 50 % weaker than that of the C 6‐ring. analyzed the ring currents of most of these structures. 13, 14, 15 They found that both rings in C 6I 6 2+ follow the Hückel's rule and proposed C 6(SeH) 6 2+, C 6(TeH) 6 2+, C 6(SeH 2) 6 2+ as viable candidates. Some derivatives of this dication were also explored as putative concentric and double aromatic species by Hatanaka and coworkers 12 via Nucleus Independent Chemical Shift (NICS) computations. 9, 10, 11 The carbon ring is, in principle, π‐delocalized, and the external iodine ring is concomitantly σ‐delocalized, so it is an organic double aromatic system. 9 The authors suggested that C 6I 6 2+ is a molecule with two concentric rings, one formed by the internal C 6‐ring, and the other one by the outer iodine atoms. 7, 8 In 1988, Sagl and Martin synthesized a fascinating system with formula C 6I 6 2+, which is obtained through hexaiodobenzene oxidation. 2, 3, 4, 5, 6 In aromatic systems composed exclusively by metals, both σ‐ and π‐electrons are delocalized (multiple aromaticity). For almost 150 years, aromaticity has been used to explain exclusively the properties of benzene derivatives (or similar ring systems) as a consequence of the π‐electrons delocalization in the ring, 1 but quite recently it has been extended to inorganic compounds.
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