Multifunctional metal complex systems emerging from analytical chemistry for theranostic applications.

Metal complexes have long played a pivotal role in analytical chemistry due to their ability to detect and separate ions through the synergistic interaction between metal centers and ligands. This functionality can be further enhanced by integrating metal complexes non-covalently with various media, such as materials or separation platforms. Over the past four decades, the author has explored metal complex systems, including thiacalixarene-lanthanide(III) complexes, diradical platinum(II) complexes, and MOF-74, which exhibit a broad spectrum of functionalities spanning analytical applications to theranostics. Examples discussed in this review include luminescent supramolecular sensors for soft-metal ions, upconverting complexes, near-infrared light-absorbing probes for pH and hydrophobic cavities, magnetic resonance imaging (MRI), photoacoustic imaging, photothermal therapy, and neutron capture therapy. The multifunctionality of these systems arises from their cooperative, synergistic, and supramolecular nature, underpinned by non-covalent interactions among their components. Analytical chemistry has been, and will continue to be, a cornerstone for the discovery and development of such multifunctional metal complex systems.