Ring Expansion of Spiro-thiolactam in Rhodamine Scaffold: Switching the Recognition Preference by Adding One Atom
摘要:
A new rhodamine spiro scaffold with a six-membered reactive ring was developed by inserting a nitrogen atom in the known probe rhodamine B Spiro thiohydrazide, which switched the recognition preference of the probe from Hg2+ to Cu2+. This probe is shown to be an efficient "turn-on" fluorescent chemodosimeter for Cu2+ in a neutral aqueous medium. Mechanism studies suggested that the probe opened its spiro-ring by a Cu2+-induced transformation of the cyclic thiosemicarbazide moiety to an isothiocyanate group.