D Copolymerizable with

The photo-induced charge-transfer copolymerization entity consists of a donor monomer and an acceptor monomer, without initiator. Reported combinations usually consist of an aryl vinyl monomer as the donor component and a 1,2-disubstituted vinyl monomer as the acceptor component. 

Another acceptor is fumaronitrile (FN). In spite of its lack of absorption above 300 nm, the partners or the CT complexes may absorb light and thus bring about polymerization. In studying 2-VN/FN system, Shirota obtained not only 1 1 alternating copolymer but also several cycloaddition products [26]  

The photocopolymerization of the N- vin y lin d ole/FN system yielded an alternating copolymer with partial addition of FN at the electron-rich 3-position of the indole ring [27]  

Acrylonitrile (AN), a weak electron-accepting but very polar monomer, was also reported to photocopolymerize with donor monomers, such as St [28], isobutyl vinyl ether [29], or butadiene [30]. 

Generally, the photo-induced charge-transfer copolymerization follows a radical mechanism and produces alternating copolymers. Accompanying cyclobutane formation is usually observed, which provides information for understanding the mechanism. 

---