10.1021/ol0507470.s001 Eun Jin Cho Eun Jin Cho Byung Ju Ryu Byung Ju Ryu Young Ju Lee Young Ju Lee Kye Chun Nam Kye Chun Nam Visible Colorimetric Fluoride Ion Sensors American Chemical Society 2005 urea Visible Colorimetric Fluoride Ion Sensors diaminonaphthalene fluoride ions naphthalene compounds isocyanate color change 2005-06-23 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Visible_Colorimetric_Fluoride_Ion_Sensors/3280942 Five new urea derivative naphthalene compounds were synthesized by a reaction of 1,8-diaminonaphthalene and the corresponding isocyanates and showed a distinct color change only when treated with fluoride ions.