An alkyne-appended, click-ready Pt(II) complex with an unusual arrangement in the solid state

Abstract

To better understand the range of cellular interactions of Pt(II) -based chemotherapeutics, robust and efficient methods to track and analyze Pt targets are needed. A powerful approach is to functionalize Pt(II) compounds with alkyne or azide moieties for post-treatment conjugation through the azide-alkyne cycloaddition (click) reaction. Herein, we report an alkyne-appended cis-diamine Pt(II) compound, cis-[Pt(2-(5-hexynyl)amido-1,3-propanediamine)Cl2] (1), the X-ray crystal structure of which exhibits a combination of unusual radially distributed CH/π(C≡C) interactions, Pt-Pt bonding, and NH:O/NH:Cl hydrogen bonds. In solution, 1 exhibits no Pt-alkyne interactions and binds readily to DNA. Subsequent click reactivity with nonfluorescent dansyl azide results in a 70-fold fluorescence increase. This result demonstrates the potential for this new class of alkyne-modified Pt compound for the comprehensive detection and isolation of Pt-bound biomolecules.

Keywords: bioorthogonal chemistry; click chemistry; fluorescent probes; metallodrugs; platinum.