Chemical carbazole copolymers

CHART 4.25 Chemical structure of electrophosphorescent fluorene copolymers where the holetransporting carbazole units have been introduced in the polymer backbone. 

Fig. 11.21 Chemical structures of carbazole homo- and copolymers studied by van Dijken et al. (reproduced from [87]).

Tokito et al. [85] studied a series of copolymers based on a nonconjugated backbone, having carbazole and emissive Ir-complexes in the side chain. Even though the chemical structures of these polymers are quite simple, rather high quantum efficiencies (3 %, 9 % and 5 % for blue, green and red emission, respectively) were reported in a single-layer device structure. 

Five-membered heterocyclic amines have been attracting attention for a long time. Their antioxidant effect was confirmed in model experiments. Derivatives of indole and carbazole are HS for PVC and copolymers of vinyl chloride [92], Some indoles are medical or biological AO protecting against chemical carcinogenesis or chemically induced hepatoxicity [93]. 6-Hydroxycarbazole suppresses oxidation of methyl linoleate, its sacrificial transformation yields a QI. 2,2-Disubstituted l,2-dihydro-3-oxo(or phenylimino)-3//-indoles (15a, b, R = Me, Et) have a potential importance as HS for PO [36]. 

Chemical structures of investigated azoaromatic polymers and copolymers, and carbazole containing azoaromatic polymers and copolymers as described by various workers (Angiolini et al., Sperotto et al. and others [52-64]) with detailed methodology and evaluation, a comparative description of their work is elaborated in Table 2. 

Finally, it is worth noting that optically active polymers containing pendant carbazole units have been prepared by attachment of the carbazole group to chemically activated, optically active macromolecules, such as coisotactic copolymers of chiral a-olefins and p-chloromethyl styrene... 

The side fuUerenation of poly(epoxypropylcarbazole) (PEPC) 57 has been achieved by grafting Ca) via a Friedel-Crafts reaction (Figure 2.5) [56]. Analogously, the same synthetic strategy applied to polyvinylcarbazole (PVK) led to chemically modified PVK copolymer, in which, after laser flash photolysis, photoinduced electron transfer between and inter- and intrachain carbazole units takes place (polymer 58 - Figure 2.5) [57]. Kang and coworkers have exploited this behavior... 

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