Luminescent rhenium(I) polypyridine fluorous complexes as new biological probes

We present the synthesis and characterization of luminescent biological probes derived from rhenium(I) polypyridine fluorous complexes [Re(Me₂ bpy)(CO)₃(py-Rf-R)](PF₆) (R = NH₂ (1), NCS (2), TU-C₂H₅ (3)). The photophysical properties of these complexes have been studied. The fluorous complex 2 has been used to label glutathione (GSH) and bovine serum albumin (BSA). The photophysical properties of the resultant bioconjugates have been studied. The isolation of the luminescent fluorous rhenium-GSH conjugate from a mixture of twenty amino acids has been demonstrated using fluorous solid-phase extraction (FSPE). Additionally, the cytotoxicity of complexes 1 and 3 toward HeLa cells has been examined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cellular uptake properties of complex 3 have been investigated by laser-scanning confocal microscopy.