Two-color emissive probes for click reactions†
CuI-catalyzed azide–alkyne cyclization (CuAAC) is the paradigmatic click reaction of continuous interest. Especially fluorogenic and FRET probes have become indispensable tools for life sciences. Here, we present a fluorescent alkyne for monitoring CuAAC, which undergoes a bathochromic shift upon reaction. Application in single-molecule and catalysis research is foreseen.