Dibenzazepine Bridged Network Polymeric Phthalocyanines as Degradable Heterogeneous Photocatalysts

Abstract

Abstract Recyclability and energy efficiency are inevitable requirements in today´s synthetic materials, as well as functional efficiency. Network polymeric phthalocyanines (NP‐Pcs) are versatile molecular frameworks which widely utilized in energy and electron transfer demanding applications, but light hasn´t played a role before in their “design and degradation”. Herein, we introduce photodynamic dibenzazepine moiety into NP‐Pcs to obtain degradable heterogeneous photocatalysts (NP‐ZnPc and NP‐CoPc). Singlet oxygen generation efficiency of NP‐ZnPc is found to be high, almost completely quenching the absorbance of diphenylisobenzofuran (DPBF) within 30 s upon red light (λ = 630 nm) irradiation. Supplementary reactions show that NP‐ZnPc has the capability to oxidize methylphenyl sulfide with 100% yield in 4 h reaction time. Subsequently, PET‐RAFT polymerization of 2‐hydroxyethyl methacrylate is successfully initiated by NP‐ZnPc in the presence of a chain transfer agent upon red light ( λ  = 647 nm) irradiation. The linearity in the increase in molecular weight (14,400–21,200 g/mol) and the decrease in monomer concentration (ln([ M ] 0 /[ M ] t  = 0.6–3.4) demonstrate the living characteristic of PET‐RAFT polymerization. Thanks to its heterogeneous nature, NP‐ZnPc is readily recovered and reused after polymerization up to three consecutive cycles without significant loss of performance. Notably, complete degradation of NP‐Pcs was achieved under 254 nm light irradiation.