Luminescent amphiphilic Pt(II) complexes and their assemblies

Photoactive transition metal complexes (TMCs) have received a great deal of attention because of their rich and peculiar physico-chemical and redox properties. The growing interest in TMCs is currently driven by their potential use as markers for in vivo bioimaging applications.1,2 Amphiphilic molecules proved to be ideal for achieving this kind of goal, possessing soluble and stable properties in aqueous media and a good degree of hydrophobicity as well. The high tendency of square planar Pt(II) complexes, containing conjugated ligands, to self-assemble in supramolecular structures can be exploited in principle to significantly enhance the emissive properties because of the formation of new excited states (metal-metal ligand charge transfer bands, MMLCT) and an increasing rigidity due to the packing of the units. In this contribution we describe the synthesis and characterization of a series of luminescent amphiphilic platinum compounds, soluble in water, based on a N^N^N pyridil-triazolate and functionalized with different ancillary ligands.3 The photophysical properties of the here proposed complexes were deeply investigated proving their potential as novel luminescent probes for in vivo cellular imaging.