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

We present a red light-activated zincII bis(dipyrrin) symmetry breaking charge transfer (SBCT) architecture, showing a large molar absorption coefficient (epsilon = 15.4 x 104 M-1 cm-1), high reactive singlet oxygen generation efficiency (phi Delta approximate to 0.8) and long-lived triplet state (tau T = 150 mu s) compared to the donor-acceptor analogue dipyrrin-BF2 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. The first example of a red-light operable photosensitizer with efficient symmetry breaking charge transfer induced intersystem crossing (SBCT-ISC) is presented and potential in the polymerization of methyl methacrylate is demonstrated.