Confocal fluorescence microscopy studies of a fluorophore-labeled dirhodium compound: visualizing metal-metal bonded...

The new dirhodium compound [Rh2(μ-O2CCH3)2(η(1)-O2CCH3)(phenbodipy)(H2O)3][O2CCH3] (1), which incorporates a bodipy fluorescent tag, was prepared and studied by confocal fluorescence microscopy in human lung adenocarcinoma (A549) cells. It was determined that 1 localizes mainly in lysosomes and mitochondria with no apparent nuclear localization in the 1-100 μM range. These results support the conclusion that cellular organelles rather than the nucleus can be targeted by modification of the ligands bound to the Rh2(4+) core. This is the first study of a fluorophore-labeled metal-metal bonded compound, work that opens up new venues for the study of intracellular distribution of dinuclear transition metal anticancer complexes.