Synthesis and self-organization of fluorene-conjugated bisimidazolylporphyrin and its optical properties.

A conjugated-bisimidazolylporphyrin bridged by bis(ethynylfluorene) was synthesized and organized into linear polymer through self-coordination having mean molecular weights, M(w) and M(n), of ~2.1 × 105 Da and ~1.6 × 105 Da, respectively. A large two-photon absorption cross section value of 3.4 × 105 GM (per dimer unit) was observed. This value was comparable to that of the previously reported self-assembled linear polymer consisting of butadiyne-bridged imidazolylporphyrins. The two-photon absorption properties could be controlled by tuning the wavelength and absorption intensity of the one-photon absorption.