A novel europium(III) complex with versatility in excitation ranging from infrared to ultraviolet.

One- and two-photon absorption properties of a novel europium(III) complex containing a hemicyanine cation are investigated in this paper; in which the sensitization wavelength of europium(III), induced by beta-diketonate ligands, is in the ultraviolet range, and the hemicyanine(aminostyrylpyridinium) cation extends the sensitization wavelength of Eu(III) to visible region. Furthermore, under 1.06 mu m ultrashort pulse laser excitation, the complex exhibits effective europium(III) luminescence induced by the two-photon absorption of the hemicyanine cation. Therefore, this new europium(III) complex with excitation bands in the near infrared, visible and ultraviolet ranges. Since the 1.06-mu m ultrafast laser is one of the most frequently used laser sources and 1.06 mu m is an 'optical window' for cells and tissues, the results suggest that this kind of complex has promising applications in deep-penetrating and high quality bioimaging in vivo.