Adaptive aromaticity in S0 and T1 states of pentalene incorporating 16 valence electron osmium

Aromaticity is a fundamental chemical concept of ever-increasing diversity. According to Hückel’s and Baird’s rules, cyclic conjugated species with 4n+2 π-electrons are aromatic in the singlet electronic ground state (S0) and antiaromatic in the lowest triplet state (T1), and vice-versa. Thus, species with aromaticity in both states have not yet been reported.

Congratulations to Jingjing, Yulei, and Ke for their paper accepted in Chem. Commun.


Unexpected Higher Stabilisation of Two Classical Antiaromatic Frameworks with a Ruthenium Fragment over Osmium Counterpart: Origin Probed by DFT Calculations

Jingjing Wu,   Yulei Hao,   Ke An and   Jun Zhu  

Planar Möbius aromatic pentalenes incorporating 16 and 18 valence electron osmiums

Aromaticity, a highly stabilizing feature of molecules with delocalized electrons in closed circuits, is generally restricted to ‘Hückel’ systems with 4n+2 mobile electrons. Although the Möbius concept extends the principle of aromaticity to 4n mobile electron species, the rare known examples have complex, twisted topologies whose extension is unlikely. Here we report the realization of osmapentalenes, the first planar Möbius aromatic complexes with 16 and 18 valence electron transition metals.