posted on 2021-08-31, 20:05authored byHimadri
S. Karmakar, Chandan Kumar, Neha Rani Kumar, Sarasija Das, Abhijeet R. Agrawal, Nani Gopal Ghosh, Sanjio S. Zade
Arene-fused
selenophenes were synthesized by a redox neutral process
from arylethynyl substituted polycyclic arenes using selenium powder
in refluxing N-methyl-2-pyrrolidone (NMP) with the
assistance of the residual water in NMP as a catalytic proton source.
The site-selective nature of this selenocyclization produces trans-alkenes as a competitive product, which is dependent
on the π-electron donation ability of polycyclic arenes and
the kind of arylethynyl group attached to it. DFT calculations were
performed to understand the site selectivity in the selenophene formation
reaction. The HOMO coefficient on the carbon adjacent to carbon having
arylalkyne substituent of the polycyclic arene correlates with the
selenocyclization tendency of the substrate. The wavelength of absorption
and emission and quantum yield of emission increase with increasing
the number of fused benzene rings in the polycyclic unit (from naphthalene
to pyrene).