The application of aromaticity and antiaromaticity to reaction mechanisms

Probing Near-infrared Absorbance of E and Z Diazene Isomers via Antiaromaticity

“…We have demonstrated that the antiaromaticity contributes to significant red shifts at the main transition bands through TD-DFT calculations, in line with the experimental study by Zhang’s group very recently . This work highlights a potential application of antiaromaticity in photochemistry, similar to our previous finding on the application of such a concept in stabilizing radicals and radical anions. ,, …”

Adaptive Aromaticity in 18e Metallapentalenes

“…It is found that complexes 1 , 2 , and 5 exhibit adaptive aromaticity, supported by HOMA, ΔBL, NICS(1) zz , AICD, ICSS zz , π-EDDB_F, and ΔFBO analyses. Trying aromaticity indices as much as possible is always recommended, as using a single index is dangerous and might cause a wrong judgment . The localized spin electrons in the T 1 state could be attributed to one of the key factors for T 1 state aromaticity, whereas the M–C bond order could be regarded as the key factor for the S 0 state aromaticity by the FBO analysis.…”

“…Trying aromaticity indices as much as possible is always recommended, as using a single index is dangerous and might cause a wrong judgment. 3 The localized spin electrons in the T 1 state could be attributed to one of the key factors for T 1 state aromaticity, whereas the M−C bond order could be regarded as the key factor for the S 0 state aromaticity by the FBO analysis. This study makes a step forward in the development of the concept of adaptive aromaticity as well as organometallic chemistry.…”

“…As is well known, aromaticity is a fundamental concept in chemistry. − In 1931, Erich Hückel investigated the molecular orbital theory of π-conjugated hydrocarbons and provided the basis for the [4 n + 2] rule of aromaticity . Later in the 1960s, Dewar proposed an explanation of Hückel’s theory .…”

Adaptive σ aromaticity in the rhenacyclopropene rings

“…Aromaticity is one of the most fundamental concepts in chemistry, 1,2 which has attracted considerable attention and discussion from experimental and theoretical chemists 3,4 since Kekulé proposed the benzene structure. 5 In addition, this concept has wide applications in materials, [6][7][8][9][10] reaction mechanism 11 and pharmaceutical science. 12 According to Hückel's rule, [13][14][15] the planar conjugated species with [4n + 2] π electrons in the lowest singlet state (S 0 ) show aromaticity whereas the ones with [4n] π electrons in the lowest triplet state (T 1 ) display aromaticity according to Baird's rule.…”