5-Azido-2-nitrobenzoic acid N-hydroxysuccinimide ester is a nitrate-containing, aryl azide-based, amine- and photoreactive crosslinker. Typically, the amide bond formation occurs in the pH range 6.5-8.5. Secondary bonding has been seen to occurs during UV irradiation (250-350 nm) via reactive nitrene. The latter bonding is rapid and non-specific. Note that the nitro substituent provides an absorption band at a longer wavelength compared to simple aryl azide.
