C–H Activation-Based Multicomponent Polyannulations toward Fluorescent Heteroaromatic Polyelectrolytes for Sunlight-Driven Antibacterial Coatings

The
development of facile and efficient synthetic methods for functional
polyelectrolytes bearing charges on main chains is an important, yet
challenging task. Herein, we develop a straightforward C–H
activation-based multicomponent polyannulation method that can efficiently
transform readily available internal diynes, aldehydes, and amines
into diverse functional main-chain charged polyelectrolytes with high
molecular weights (Mw up to 55000 g/mol)
in high yields of up to 99.2%. Multisubstituted polycyclic heteroaromatic
cations are generated in situ in polymer backbones as π spacers
via successive C–H activation/annulation processes in a one-pot
manner, which are hard to achieve by conventional methods. Benefiting
from the unique structures, the obtained polyelectrolytes all exhibit
excellent solubility and film-forming ability, high thermal and morphological
stability, and readily tunable aggregate-state luminescence properties.
Remarkable light-enhanced bactericidal activity against Gram-positive
bacteria was achieved due to the efficient reactive oxygen species
generation capability of the polycations. Furthermore, the polyelectrolyte
thin films can function as good sunlight-triggered antibacterial coating
materials on various substrates, demonstrating application potential
for the gentle sunlight sterilization of medical facilities.