DOTA-(t-Butyl)3-PEG5-azide contains DOTA-(t-butyl) and azide moieties. The DOTA-(t-Butyl) is soluble in DMF and DCM. The t-Butyl groups can be removed under acidic conditions to produce free carboxylic acid. The azide group is commonly used in copper-catalyzed Click Chemistry reactions with alkynes, DBCO and BCN. The PEG chain increases the water solubility of compounds in aqueous media.