Luminescent Cyclometalated Platinum(II) Complex Forms Emissive Intercalating Adducts with Double-Stranded DNA and RNA: Differential Emissions and Anticancer Activities

Luminescent metallo‐intercalators are potent biosensors of nucleic acid structure and anticancer agents targeting DNAs. There are few examples of luminescent metallo‐intercalators which can simultaneously act as emission probes of nucleic acid structure and display promising anticancer activities. Herein, we describe a luminescent platinum(II) complex, [Pt(C^N^N)(C≡NtBu)]ClO4 (1 a, HC^N^N= 6‐phenyl‐2,2′‐bipyridyl), that intercalates between the nucleobases of nucleic acids, accompanied by an increase in emission intensity and/or a significant change in the maximum emission wavelength. The changes in emission properties measured with double‐stranded RNA (dsRNA) are different from those with dsDNA used in the binding reactions. Complex 1 a exhibited potent anticancer activity towards cancer cells in vitro and inhibited tumor growth in a mouse model. The stabilization of the topoisomerase I–DNA complex with resulting DNA damage by 1 a is suggested to contribute to its anticancer activity. Komplexe Therapie: Der lumineszierende PtII‐Pinzettenkomplex [Pt(C N N)(CNtBu)]ClO4 interkaliert in DNA und bildet einen ungewöhnlichen emissiven Exciplex. Das Emissionsprofil und die Lebensdauer des angeregten Zustands hängen von der Nucleinsäurestruktur ab, was zur Differenzierung zwischen dsRNA und dsDNA genutzt wird. Der Komplex zeigt starke Cytotoxizität in vitro und unterdrückt das Tumorwachstum in einem Tiermodell.