Synthesis, crystal structures and two-photon absorption properties of a series of terpyridine-based chromophores

A series of 2, 2′: 6′, 2′′-terpyridine-based chromophores (L1, L2, L3 and L4) with intramolecular ‘push–pull’ structure have been designed and synthesized. The single crystals of L1, L2 and L4 were obtained and solved by X-ray diffraction analysis. The photophysical behavior and the connections between structure and properties of the chromophores were investigated both experimentally and theoretically. It is revealed that the chromophores exhibit sensitive single-photon-excited fluorescence emission with high quantum yields, strong two-photon-excited fluorescence and large two-photon absorption cross sections, especially in DMF solution. It was also found that methylformate units as a peripheral groups attached to the triphenylamine moiety influence the structures, photophysical properties of the chromophores obviously.

► Four terpyridine-based chromophores were confirmed by X-ray diffraction analysis.
► The molecular geometry optimization is based on the crystal data.
► The connections between structure and properties of them were investigated.
► The chromophores exhibit large two-photon absorption, especially in DMF solution.
► The methylformate attached to the triphenylamine unit influence their properties.