Reaction of a N-anthrylcarbonylthiourea derivative with Cu2+ or H+: unusual rearrangement to a highly fluorescent S-(9-anthryl)isothiouronium salt

For the fluorescent ligand 1-(9-anthrylcarbonyl)-3,3-tetramethylenethiourea with Cu(ClO4)(2) or strong acids an unusual rearrangement reaction occurre d yielding a highly emissive S-(9-anthryl)isothiouronium salt. This rearran gement product was characterised by NMR spectroscopy and X-ray analysis as well as absorption and fluorescence spectroscopy. Additionally, the chemica l and complexation behaviour of the N-anthrylcarbonylthiourea derivative is compared to that of its naphthyl and phenyl analogues.