A novel ferrocenyl–naphthalimide as a multichannel probe for the detection of Cu(ii) and Hg(ii) in aqueous media and living cells

Abstract

A novel ferrocenyl–naphthalimide multichannel probe 1 was designed and synthesized using a facile method. The color of the solution containing probe 1 changed from yellow to colorless upon the addition of Cu²⁺ or Hg²⁺. Interestingly, probe 1 exhibited highly selective fluorescent turn-on for Cu²⁺ and turn-off for Hg²⁺ in aqueous solution. Probe 1 was an electrochemical Cu²⁺ and Hg²⁺ ion sensor, in which the Fc/Fc⁺ redox couple was significantly shifted (ΔE_1/2 = 178 mV and ΔE_1/2 = 53 mV, respectively) upon complexation. Therefore, probe 1 can act as a naked-eye chemosensor, as well as an electrochemical and a fluorescent probe for Cu²⁺ and Hg²⁺. Furthermore, this is the first reported probe that can be used for the bifunctional fluorescent detection of intracellular Cu²⁺ and Hg²⁺ by fluorescent imaging studies. These characteristics give this probe considerable potential in the study and analysis of Cu²⁺ and Hg²⁺ in complex biosystems.