Figure 1.

(a) Schematic representation of copper-free clicked triazoles in which the biomolecule (e.g., antibody) and the labeling moiety (e.g., the PET radionuclide ¹⁸F) could readily be attached to either the triazole or eight-membered ring side chain. (b) Structures of envisioned bifunctional cyclooctyne reagents 1–4 that would combine with alkyl azides to form triazoles (R is the ¹⁸F-bearing labeling motif or biomolecule).