β-Lactam Bioconjugates Bearing Luminescent Platinum(II) Tags: Synthesis and Photophysical Characterization

Two novel neutral complexes based on platinum metal ions, a tridentate ligand, and a pyridine bearing a β-lactam unit have been synthesized and their photophysical properties investigated. The complexes show interesting emission properties that, in the solid state, are dominated by the formation of aggregates due to the square-planar geometry of the PtII species. Importantly, the formation of closed-shell metal···metal interactions in such aggregates leads to new excited states that conveniently allow excitation in the visible region. The combination of the biologically active azetidinone agent and the intense and long-lived emission are of particular interest for developing efficient multifunctional biomedical systems.