Description General description Acid functionalized cyclooctyne derivative. Cyclooctynes are useful in strain-promoted copper-free azide-alkyne click chemistry reactions. This azadibenzocyclooctyne will react with azide functionalized compounds or biomolecules without the need for a Cu(I) catalyst to result in a stable triazole linkage. Application Dibenzocyclooctyne-acid may be used for the surface modification of eight-arm poly(ethylene glycol), to make it susceptible to strain promoted alkyne-azide cycloaddition (SPAAC) with PEG-bis-azide leading to the formation of hydrogels. These hydrogels are useful for protein immobilization. Packaging 10 mg in clear glass bottle