Synthesis of Fluorogenic Arylureas and Amides and Their Interaction with Amines: A Competition between Turn-on Fluorescence and Organic Radicals on the Way to a Smart Label for Fish Freshness

We describe the synthesis of fluorogenic arylureas and amides their interaction with primary or secondary amines under air light in organic-aqueous mixtures to give rise a new class persistent organic radicals, described on basis electron paramagnetic resonance (EPR), as well UV–vis, fluorescence, NMR, quantum mechanics calculations, prospective use multi-signal reporters smart label for fish freshness.