Sulfur-doped anthanthrenes as effective organic photocatalysts for metal-free ATRP and PET-RAFT polymerization under blue and green light†

Abstract

Organocatalytic atom transfer radical polymerization (O-ATRP) as a metal-free controlled polymerization method represents an appealing approach for polymer synthesis in which the organic photocatalyst is critical to the polymerization efficiency and control. Herein, we introduce sulfur-doped anthanthrene (SDA) as a new and effective organic photoredox catalyst (OPC) for O-ATRP by following the photocatalyst design logic of heteroatom-doping of polycyclic arenes (HDPA). SDA could promote the O-ATRP of methacrylate monomers with good control on both molecular weight and low dispersity at 10–100 ppm catalyst loadings under visible light, even under green light in the absence of external electron donors. Further extension of the SDA catalyst to photoinduced electron/energy transfer addition–fragmentation chain-transfer (PET-RAFT) polymerization under green light is also demonstrated.