Polymers Based on p-Phenylenephosphine Units

Cyclic voltammetry revealed that the N-atoms of 86a, 88a and 91a are oxidized at lower potentials than the trivalent P atoms. Comparison of these data with those observed with model compounds shows a very weak electronic delocalization via the P centers for copolymers 86a and 91a. In contrast, the low first oxidation potential observed for 88a (Table 4.5) is assumed to result from an electronic communication between the N moieties through the connecting P centers [59b]. The equivalence of the oxidation potentials for the oxidized polymers (Table 4.5) suggests the presence of electronically isolated triarylamine fragments in these derivatives. Note that the involvement of the P lone pair in jt-delocalization 

In summary, linear phosphorus-containing poly(N-arylanilines) can be readily obtained by palladium-catalyzed C-P bond formation. Their physical properties strongly support electronic delocalization through o3-P centers along the polymer backbone, something that is switched off upon oxidation of the P atoms. 

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