Novel aminoalkyl tris-cyclometalated iridium complexes as cellular stains.

Herein we report the synthesis and investigation of the properties of two tris-cyclometalated luminescent iridium complexes. These complexes are the simple derivatives of fac-[Ir(ppy)3] bearing amino alkyl groups on one of the phenylpyridine rings. The complexes are highly emissive and exhibit structured emission peaks in aqueous solution while having only broad unstructured emission in organic solvents. The complexes have been shown to be taken up by NIH-3T3 and PC3 cells, where they localize in the lysosomes and remain emissive with lifetimes in the microsecond domain.