Luminescent platinum complexes having sensing functionalities

Square-planar platinum(II) complexes often exhibit intense color and luminescence when they are stacked via self-assembly or bridging by ligands. The origin of the color and luminescence are the metal-metal electronic interactions, and thus, remarkable changes in color (i.e., chromism) are expected by controlling the Pt center dot center dot center dot Pt interactions. The molecular arrangement of the assembled complex systems is sensitive to environmental factors such as temperature, pressure, solvent, and vapor. This account focuses on the sensing functionalities of luminescent platinum(II) complexes with 2,2'-bipyridine or its derivatives toward their environment. Especially, luminescence changes that are induced by the vapor molecules will be examined from the viewpoint of chemical sensing. The vapochromic behavior and structural aspects of the mononuclear and dinuclear platinum(II) complexes are discussed.