A High-Performing Metal-Free Photoactivatable NO Donor with a Green Fluorescent Reporter

We report herein a novel nitric oxide (NO) donor activatable by visible blue light with an in-built green fluorescence reporter. This NO photodonor, based on the amino-nitro-benzofurazan chromogenic skeleton, releases NO in solution with a quantum yield ΦNO=0.15 which increases up to 0.80 in Pluronic® micelles, the largest values ever reported for nonmetal-containing NO donors activatable by visible light. Besides, the large contrast between the fluorescence emission of the chromogenic moiety after and before the NO release (> 10) permits the easy and in real-time quantification of the amount of NO released, without the addition of external fluorescent probes. This NO photodonor can also be effectively entrapped in a Pluronic-based thermoresponsive hydrogel with excellent preservation of its photochemical and photophysical behaviour. These properties, together with the facile synthetic procedure, make the present compound an intriguing candidate for fundamental and potential applicative research studies where spatiotemporally regulated NO delivery is required.