Synthesis and physical properties of azo-ferrocene oligomers and polymers

Reaction of 1.1′-dilithioferrocene with N2O gave azo-bridged ferrocene oligomers andpolymers. Two trimers, Fc-Fc′-N2-Fc (1) and Fc-N2-Fc′-N2-Fc (2) were isolated, where Fc and Fc′ refer to (η5-C5H5)Fe(η5-C5H4−) and Fe(η5-C5H4−)2, respectively. Oxidation processes of the trimers via mixed-valence states are entirely different from the process of terferrocene due to the strong electron-withdrawing effect of the azo group. Polymers with high content of azo-ferrocenyl units were prepared under high pressure conditions of N2O. The CT complex of the polymer with TCNQ was prepared and its conductivity was slightly enhanced upon irradiation of NIR and visible lights.