Conception and Evaluation of Fluorescent Phosphine‐Gold Complexes: From Synthesis to in vivo Investigations

A phosphine gold(I) and phosphine‐phosphonium gold(I) complexes bearing a fluorescent coumarin moiety were synthesized and characterized. Both complexes displayed interesting photophysical properties: good molar absorption coefficient, good quantum yield of fluorescence, and ability to be tracked in vitro thanks to two‐photon imaging. Their in vitro and in vivo biological properties were evaluated onto cancer cell lines both human and murine and into CT26 tumor‐bearing BALB/c mice. They displayed moderate to strong antiproliferative properties and the phosphine‐phosphonium gold(I) complex induced significant in vivo anti‐cancer effect. A promising gold‐based optical theranostic agent was conceived. This phosphine‐phosphonium gold(I) complex can be tracked by two‐photon imaging thanks to a coumarin moiety. It displayed strong anti‐proliferative properties against cancer cell lines and induced an anti‐cancer effect in vivo.