We previously reported the synthesis of the metal-based fluorescent probes MBFh1 and MBFh2 for hydrogen peroxide (H2O2) imaging, which release the red-emitting fluorophore resorufin, whose response rate is significantly faster than that of other nonmetal-based H2O2 probes, upon reacting with H2O2. In this study, we have synthesized the new fluorescent probe MBFh3 1 and its ester derivatives 2 and 3, in which a mononuclear nonheme iron(III)–monoamido complex and a 3′-O-methyldihydrofluorescein derivative are connected via a propane linker. Probes 2 and 3 are methyl and 1-(ethoxycarbonyloxy)ethyl ester derivatives of 1, respectively. These probes rapidly react with H2O2 to release green-emitting 3′-O-methylfluoresceins. Fluorescent microscopy studies using HeLa and A431 cells showed that intracellular H2O2 can be visualized using probes 1 and 2, but not 3.
2014 The Chemical Society of Japan