Structural conversion and intramolecular electron transfer in ferrocenylanthraquinones triggered by Keggin type of heteropoly acid serving as proton source

Intramolecular electron transfer triggered by proton and the mechanism of structural conversion in a ethynylene-bridged ferrocene-anthraquinone organic elec-tron donor(D)-acceptor(A) p-conjugated system (1-FcAq) in the presence of a Keggin type heteropoly acid as proton source are discussed. Heteropoly acids can stabilize the pro-tonated ethynylene-bridged ferrocene-anthraquinone conju-gated complex, and the stable protonated complex has been isolated in air and characterized by elemental analyses, IR, 1H NMR, and CV. Upon the inducement of proton, electron transfer from ferrocene moiety (Fc) to anthraquinone moiety (Aq) causes the rearrangement of the conjugated system to create a fulvenecumulene structuere.