Triangulenes and theirs ions: reaching the limits of Clar's rule

Abstract

The triangulenes and their closed-shell ions are a family of polycyclic aromatic hydrocarbons (PAH) that have possible applications in fields as different as spintronics or catalysis. However, the electron delocalization...

Synthesis and Isolation of a Kinetically Stabilized Crystalline Triangulene

“…The harmonic oscillator model of aromaticity (HOMA) values , of rings A and B obtained by the X-ray structure are 0.76 and 0.71, respectively (Figure c). The absence of strong local aromaticity indicates that unpaired electrons of 1d delocalize over the triangulene core structure . The NICS(1) zz values calculated for 1a are −10.8 ppm for ring A and −8.6 ppm for ring B (Figure c), which is consistent with the HOMA values.…”

“…The absence of strong local aromaticity indicates that unpaired electrons of 1d delocalize over the triangulene core structure. 31 The NICS(1) zz values calculated for 1a are −10.8 ppm for ring A and −8.6 ppm for ring B (Figure 2c), which is consistent with the HOMA values. The anisotropy of the induced current density (ACID) 32,33 plot of 1a also suggests the aromatic character of rings A and B (Figure S2).…”

BenzAI: A Program to Design Benzenoids with Defined Properties Using Constraint Programming

“…Thus, we search monomeric units with stable unpaired electrons and an even number of carbons, i.e., concealed non-Kekuléan benzenoids . We know that the C 13 H 9 triangulene carries a radical localized on the second neighbor of the central carbon atom; see Figure . , There must be two such units by a monomer for the total molecule to have an even number of electrons, and these two units must not share a ring. The combination of these constraints can be handled by BenzAI.…”

Unraveling the flexible aromaticity of C13H9+/0/−: a 2D superatomic-molecule theory

“…19 These findings suggested that phenalenyl and its charged counterparts are all aromatic. However, to the best of our knowledge, their aromaticity cannot be rationalized by any known aromatic rule regarding system electrons, including the conventional Hu ¨ckel's 4n + 2 rule 20,21 for monocyclic planar conjugate systems, 22 and Clar's rule for polycyclic aromatic hydrocarbons, 23,24 To accommodate the challenges and meanwhile to understand the related electronic structures, an effective approach is to introduce the theory of superatom, 25 which refers to specific clusters that mimic the chemical property of an atom or a group of the periodic table of elements. Superatoms have been widely studied, and are capable of forming superatomic bonds in various systems.…”