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.