Structure, bonding and adaptive aromaticity in rhenium-oxo complexes: a DFT study

Abstract

In general, species could be aromatic in the ground or excited state only according to Hückel’s and Baird’s rules. Thus, adaptive aromatics are particularly rare as they can be aromatic...

Planar inorganic five-membered heterocycles with σ + π dual aromaticity in both S0and T1states

“…More precisely, it is adaptive π-aromaticity in this case because both the aromaticities in the two states stem from the π-electron delocalization. Afterwards, they continually discovered adaptive π-aromaticity in more organometallics such as metallapentalene/metallapyridinium, 11–15 metallazapentalene 16 and metallasilapentalyne complexes. 17 These contributions greatly enrich the metallaaromatic chemistry.…”

Probing the mechanism of adaptive aromaticity in metallapyridiniums

“…In addition, our previous studies on organometallic species suggest that the trend of NICS values is consistent with other aromatic indices. 31,34,65,66 So the NICS(1) zz values are used to evaluate aromaticity in this work. As shown in Fig.…”

“…The loss of triplet state aromaticity of the Ir.X species encouraged us to explore the distribution of unpaired electrons in their lowest triplet state. Moreover, recent studies have demonstrated that spin density 28,31,34,66 plays an important role in adaptive aromaticity. The Mulliken spin populations on the metal center atoms and the remaining fragment (C 4 N) of the six-membered ring in the M.X species are provided in Fig.…”

“…In short, the localized spin density of the metal center in a metallapyridinium is beneficial for achieving aromaticity in its lowest triplet state, in line with previous reports. 28,31,34,66 Bond order analysis To further probe the mechanism of the loss of triplet state aromaticity in the Ir.X species, the Fuzzy atom bond orders (FBO) 67,68 of M.X were calculated and provided in Fig. 8.…”

“…In short, the localized spin density of the metal center in a metallapyridinium is beneficial for achieving aromaticity in its lowest triplet state, in line with previous reports. 28,31,34,66…”