This work presents the first example of acid/base-responsive
and
near-infrared (NIR)-absorbing photocatalysts based on imidazole-anion-fused
perylene diimide chromophores. The photocatalysts were in situ generated
by deprotonation of imidazole-fused perylene diimide under an alkaline
environment. NIR (λ = 730 nm, 128 mW/cm2) photoinduced
atom transfer radical polymerization (ATRP) was implemented, exhibiting
high efficiency and excellent livingness under ppm level of photocatalysts
(15 ppm relative to monomer) and Cu(II) complex (10 ppm relative to
monomer) concentrations. The method showed capabilities to polymerize
behind opaque barriers (i.e., paper and pig skin) and under aerobic
condition. Notably, this work demonstrated a dual temporal control
of polymerization by adding weak base/acid and switching NIR light
on/off. The polymerization can even be halted by bubbling CO2 and was then fully recovered by adding triethylamine. The NIR photoATRP
of acrylamide monomers in aqueous solution was also performed, which
can be regulated by the change of pH.