Fluorescent antitumor titanium(iv) salen complexes for cell imaging.

Two differently substituted fluorescent salen Ti(iv) complexes were developed. One was inactive on human cancer cells, whereas the other showed high cytotoxicity. Based on live cell imaging, both complexes penetrated the cell, but were not detected in the nuclei. Moreover, the inactive complex was trapped in endocytic vesicles, whereas the active complex accumulated in the perinuclear region and inflected phototoxicity upon continuous irradiation.