The Synthesis and Physical Properties of Novel Polyaromatic Profluorescent Isoindoline Nitroxide Probes

New profluorescent mono- and di-isoindoline nitroxides (5, 11, 16 and 19) containing 9,10-diphenylanthracene and 9,10-bis(phenylethynyl)anthracene structural cores were synthesised by palladium-catalysed Suzuki and Sonogashira couplings. These nitroxide-fluorophore probes possess strongly suppressed fluorescence, even in the presence of only one nitroxide radical. Upon reduction, or reaction with other radicals, normal fluorescence emission is returned. The significant difference in fluorescence output between the nitroxides and their corresponding diamagnetic analogues makes these probes ideal tools for imaging polymer degradation using fluorescence microscopy. ( (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)