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Expanding the Palette of Phenanthridinium Cations
Author(s) -
Cairns Andrew G.,
Senn Hans Martin,
Murphy Michael P.,
Hartley Richard C.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201304241
Subject(s) - chemistry , intercalation (chemistry) , imine , halide , density functional theory , aryl , combinatorial chemistry , superoxide , computational chemistry , photochemistry , stereochemistry , catalysis , organic chemistry , enzyme , alkyl
Abstract 5,6‐Disubstituted phenanthridinium cations have a range of redox, fluorescence and biological properties. Some properties rely on phenanthridiniums intercalating into DNA, but the use of these cations as exomarkers for the reactive oxygen species (ROS), superoxide, and as inhibitors of acetylcholine esterase (AChE) do not require intercalation. A versatile modular synthesis of 5,6‐disubstituted phenanthridiniums that introduces diversity by Suzuki–Miyaura coupling, imine formation and microwave‐assisted cyclisation is presented. Computational modelling at the density functional theory (DFT) level reveals that the novel displacement of the aryl halide by an acyclic N ‐alkylimine proceeds by an S N Ar mechanism rather than electrocyclisation. It is found that the displacement of halide is concerted and there is no stable Meisenheimer intermediate, provided the calculations consistently use a polarisable solvent model and a diffuse basis set.