Product Description: Cy5-PEG2-exo-BCN is a dye derivative of Cyanine 5 (Cy5) (HY-D0821) containing 2 PEG units. Cy5-PEG2-exo-BCN contains the lyophilic bidentate macrocyclic ligand BCN, which can further synthesize macrocyclic complexes. In click chemistry, BCN reacts with molecules containing azide groups to form stable triazoles in the absence of catalysts.