title: Oxidative cyclization of N-acylhydrazones. Development of highly selective turn-on fluorescent chemodosimeters for Cu2+.
abstract: A series of N-acylhydrazones were synthesised and found to be "turn-on" fluorescent chemodosimeters for Cu(2+). Among the tested transition metal ions such as Cu(2+), Pb(2+), Zn(2+), Cd(2+), Hg(2+), and Ni(2+), a prominent fluorescence enhancement of up to 1000-fold was only observed for Cu(2+) in acetonitrile (CH(3)CN). This was indicated by an onset of unprecedented structured emission. Detailed experiments established that the highly Cu(2+) selective fluorescence enhancement resulted from an oxidative cyclization by Cu(2+)of the originally nonfluorescent N-acylhydrazones into highly fluorescent rigid 1,3,4-oxadiazoles, n-dope type blocks in optoelectronic materials. The chemodosimeters can be applied to sense Cu(2+) at nM levels in CH(3)CN and sub-microM levels in neutral aqueous environments, despite a slower response in the latter case. It is expected that these redox-based chemodosimeters might be of general applicability.
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
authors.forename: Ai-Fang
authors.initials: AF
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: He
authors.forename: Yi-Bin
authors.initials: YB
authors.lastname: Ruan
authors.forename: Zhen-Chang
authors.initials: ZC
authors.lastname: Wen
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Zhao
authors.forename: Qiu-Ju
authors.initials: QJ
authors.lastname: Jiang
authors.forename: Yun-Bao
authors.initials: YB
authors.lastname: Jiang