Flash Communication: Synthesis of Osmabenzimidazoisoquinolines from Osmabenzenes Via Classical Nucleophilic Aromatic Substitution Reactions

As one of the most important N-containing polycyclic
aromatic hydrocarbons,
benzimidazo[2,1-a]isoquinoline derivatives are of
great interest due to their unusual biological activities and photophysical
properties. Herein, we present the SNAr reaction of osmabenzene
with 1-aminoisoquinoline to access unique metal-containing benzimidazo[2,1-a]isoquinoline derivatives. Comprehensive DFT calculations,
including NICS, AICD, EDDB, and NOBD analysis, reveal the aromaticity
switching of the osmabenzene ring of the resulting osmabenzimidazoisoquinolines.
Additionally, these conjugated condensed metallacycles exhibit effective
narrowing of the HOMO–LUMO gap, resulting in red-shifted absorption
bands.