Red-light operable photosensitizer with symmetry-breaking charge transfer induced intersystem crossing for polymerization of methyl methacrylate.

We present a red light-activated zinc II bis(dipyrrin) symmetry breaking charge transfer (SBCT) architecture, showing a large molar absorption coefficient ( ε = 15.4 × 10 4 M -1 cm -1 ), high reactive singlet oxygen generation efficiency ( Φ Δ ≈ 0.8) and long-lived triplet state ( τ T = 150 μs) compared to the donor-acceptor analogue dipyrrin-BF 2 complex, highlighting the superiority of the SBCT approach. For the first time, we demonstrated the potential of a SBCT scaffold in red-light-induced methyl methacrylate (MMA) polymerization, using a dual photocatalyst excitation approach.