Difluorocarboxyfluorescein Azide, 6-isomer

2′, 7′-Difluorocarboxyfluorescein Azide, 6-isomer (also under Oregon Green 488 Azide (Oregon Green™ 6-Carboxamido-(6-Azidohexanyl), Triethylammonium Salt), 6-isomer name) is a bright, green-fluorescent azide-activated probe that reacts with terminal alkynes via a copper-catalyzed click reaction (CuAAC). It also reacts with strained cyclooctyne via a copper-free click chemistry reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures.

2′,7′-Difluorocarboxyfluorescein fluorinated analog of fluorescein that overcomes some of the key limitations of fluorescein, including greater photostability and a lower pKa (pKa ~ 4.7 versus 6.4 for fluorescein), making its fluorescence essentially pH insensitive in the physiological pH range.