A novel naphthalimide-appended salamo-type fluorescent sensor for continuous “on-off-on” detection of Cu2+ and CN− ions, sensing mechanisms and applications

Abstract

A novel naphthalimide-appended salamo-type fluorescence sensor (E)-2-hydroxy-3-methoxybenzaldehyde O-(2-((((E)-1-(3-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-2-hydroxyphenyl)ethylidene)amino)oxy)ethyl) oxime (H2L) for continuous identification of copper(II) and cyanide ions was constructed. The sensor H2L exhibited relatively high selectivity for Cu2+ in a 1:1 stoichiometric manner, and the increase of Cu2+ led to quenching of blue fluorescence, with a minimum detection limit of 9.37 × 10−9 M. In addition, the complex generated by the sensor H2L with Cu2+ could in situ recognize CN−, the L-Cu2+ complex coordinates with CN− in a 1:1 stoichiometric manner and exhibits high selectivity, and the addition of CN− results in enhanced blue fluorescence. The time response and pH effect tests demonstrated the advantages of H2L such as fast response for the continuum recognition of Cu2+ with CN− and wide pH test range. Based on the above results, an attempt was made to determine Cu2+ with CN− in spiked environmental water samples with good recoveries.