Carbohydrate-based switch-On molecular sensor for Cu(II) in buffer: absorption and fluorescence study of the selective recognition of Cu(II) ions by galactosyl derivatives in HEPES buffer

Abstract

1-(β-D-Galactopyranosyl-1'-deoxy-1'-iminomethyl)-2-hydroxynaphthalene (L₁), possessing an ONO binding core, was found to be selective for Cu²⁺ ions in N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] buffer, at concentrations ≤ 580 ppb, at physiological pH by eliciting switch-on behavior, whereas the other ions, viz., Mg²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺, caused no significant change in the fluorescence. Whereas the binding characteristics were ascertained by absorption spectroscopy, the species formed were shown by Q-TOF ES MS.