Novel panchromatic photopolymerizable matrices: N,N'-dibutylquinacridone as an efficient and versatile photoinitiator

N,N'-dibutylquinacridone (DBQA) is utilized here for the first time as a high-performance panchromatic photoinitiator for the cationic polymerization (CP) of epoxides, the free radical polymerization (FRP) of acrylates, the thiol-ene polymerization and the synthesis of interpenetrated polymer networks (epoxide/acrylate) under violet, blue, green and yellow lights (emitted from LED at 405 nm, 470 nm, 520 nm, or 594 nm, or laser diode at 532 nm). It confers a panchromatic character to the photopolymerizable matrices. Remarkably, the proposed DBQA based photoinitiating systems exhibit quite excellent efficiency (the final monomer conversion for multifunctional monomers at room temperature can reach 62% and 50% in CP and FRP, respectively) and appear as much more powerful than the camphorquinone or Eosin-Y containing reference systems for visible light. For green light, DBQA is much more reactive than the literature reference (Eosin-Y) and for blue light, a good reactivity is found compared with camphorquinone. The photochemical mechanisms are studied by molecular orbital calculations, steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques.