Highly Fluorescent Red-Light Emitting Bis(boranils) Based on Naphthalene Backbone

Ten
bis­(boranils) differently substituted at the boron atom and
iminophenyl groups were synthesized from 1,5-dihydroxynaphthalene-2,6-dicarboxaldehyde
using a simple one-pot protocol. Their photophysical properties can
be easily tuned in a wide range by the variation of substituents.
Their absorption and emission spectral bands are significantly red-shifted
(λmax = 495–590 nm, λem =
533–683 nm) when compared with simple boranils, whereas fluorescence
quantum yields are strongly improved to reach 83%. The attachment
of pendant NO2 and NEt2 groups at the opposite
positions of the π-conjugated bis­(boranil) scaffold resulted
in the formation of an unprecedented system featuring push–pull
architecture.