PERGAMON-ELSEVIER SCIENCE Acta Medica Okayama 00404039 60 43 2019 Fluorescence properties of amido-substituted 2,3-naphthalimides: Excited-state intramolecular proton transfer (ESIPT) fluorescence and responses to Ca2+ ions 151189 EN Lei Wang Division of Earth, Life, and Molecular Sciences, Graduate School of Natural Science and Technology, Okayama University Mayu Fujii Division of Earth, Life, and Molecular Sciences, Graduate School of Natural Science and Technology, Okayama University Misa Namba Division of Earth, Life, and Molecular Sciences, Graduate School of Natural Science and Technology, Okayama University Minoru Yamaji Division of Molecular Science, Graduate School of Science and Engineering, Gunma University Hideki Okamoto Division of Earth, Life, and Molecular Sciences, Graduate School of Natural Science and Technology, Okayama University 2,3-Naphthalimide derivatives incorporating trifluoroacetamido (3a) and methansulfonamido (3b) functionalities at the 1-position were prepared and their intramolecular excited state proton transfer (ESIPT) fluorescence and responses to metal ions were investigated. Compound 3a displayed normal fluorescence in the amide form in toluene and MeCN and no response to metal cations in the corresponding amidate ion form. In contrast, compound 3b gave off dual emission assignable to normal and ESIPT fluorescence. Additionally, the amidate form of compound 3b displayed off-on fluorescence response to Ca2+. No potential conflict of interest relevant to this article was reported.