Copper and iron complexes as visible‐light‐sensitive photoinitiators of polymerization

Abstract

International audienceThe utilization of visible lights for the fabrication of polymeric materials is recognized as a promising and environmentally friendly approach. This process relies on the photochemical generation of reactive species (e.g., radicals, radical cations, or cations) from well-designed photoinitiators (PIs) or photoinitiating systems (PISs) to initiate the polymerization reactions of different monomers (acrylates, methacrylates, epoxides, and vinyl ethers). In spite of the fact that metal complexes such as ruthenium- or iridium-based complexes have found applications in organic and polymer synthesis, the search of other low-cost metal-based complexes as PISs is emerging and attracting increasing attentions. Particularly, the concept of the photoredox catalysis has appeared recently as a unique tool for polymer synthesis upon soft conditions (use of light emitting diodes and household lamp). This highlight focuses on recently designed copper and iron complexes as PI catalysts in the application of photoinduced polymerizations (radical, cationic, interpenetrated polymer networks, and thiol-ene) or controlled radical polymerization under visible light irradiatio

Photocatalysts in Polymerization Reactions

“…In addition to the high photocatalytic activities of Ru, Ir, and Pt complexes, low‐cost metal complexes including iron, copper, zinc, and titanium have received increasing interest . Indeed, Cu and Fe complexes are well‐known catalysts in atom transfer radical polymerizations (ATRP, see below), but recently their photocatalytic properties have been highlighted in free radical and cationic photopolymerizations .…”

“…In addition to the high photocatalytic activities of Ru, Ir, and Pt complexes, low‐cost metal complexes including iron, copper, zinc, and titanium have received increasing interest . Indeed, Cu and Fe complexes are well‐known catalysts in atom transfer radical polymerizations (ATRP, see below), but recently their photocatalytic properties have been highlighted in free radical and cationic photopolymerizations . Copper complexes bearing a bis(2‐(diphenylphosphino)phenyl)ether chelate (Figure ) to enhance their excited‐state lifetimes presented unprecedented photocatalytic activities in the photopolymerization of acrylate and epoxide monomers by using visible‐light LEDs .…”

Recent Advances on Visible Light Metal-Based Photocatalysts for Polymerization under Low Light Intensity

“…Following the different works done on ruthenium, iridium, zinc, and copper complexes, iron complexes have been identified as potential candidates for polymerization and tested for the first time in 2015 in the context of photoredox catalysis [107][108][109][110][111][112][113]. Indeed, prior to this work, photopolymerization of acrylates or styrene with iron complexes have already been reported in the literature [114][115][116].…”

ChemInform Abstract: Photocatalysts in Polymerization Reactions

“…[46] Scheme5.Reactionmechanism for the PC/Ph 2 I + /R 3 SiH system. In addition to the high photocatalytic activities of Ru, Ir,a nd Pt complexes,l ow-cost metal complexesi ncluding iron, [47] copper, [47b] zinc, [48] and titanium [49] have received increasing interest. [20b] Indeed, Cu and Fe complexes are well-known catalysts in atom transfer radical polymerizations (ATRP,s ee below), [50] but recently their photocatalytic properties have been highlighted in free radical and cationic photopolymerizations.…”