Mitochondria-Targeted Luminescent Organotin(IV) Complexes: Synthesis, Photophysical Characterization, and Live Cell Imaging

Five fluorescent ONO donor-based organotin­(IV) complexes, <b>[Sn</b>^<b>IV</b><b>(L</b>^<b>1–5</b><b>)­Ph</b>_<b>2</b><b>]</b> (<b>1–5</b>), were synthesized by the one-pot reaction method and fully characterized spectroscopically including the single-crystal X-ray diffraction studies of <b>2–4</b>. Detailed photophysical characterization of all compounds was performed. All the compounds exhibited high luminescent properties with a quantum yield of 17–53%. Additionally, the results of cellular permeability analysis suggest that they are lipophilic and easily absorbed by cells. Confocal microscopy was used to examine the live cell imaging capability of <b>1–5</b>, and the results show that the compounds are mostly internalized in mitochondria and exhibit negligible cytotoxicity at imaging concentration. Also, <b>1–5</b> exhibited high photostability as compared to the commercial dye and can be used in long-term real-time tracking of cell organelles. Also, it is found that the probes (<b>1–5</b>) are highly tolerable during the changes in mitochondrial morphology. Thus, this kind of low-toxic organotin-based fluorescent probe can assist in imaging of mitochondria within living cells and tracking changes in their morphology.