Development of a highly selective and sensitive fluorescent chemosensory for zinc ion detection in aqueous ethanol solution: synthesis of a new aza-oxo macrocycle using high-dilution condition method

Utilizing a high-dilution condition method, a new aza-oxo macrocycle, referred to as L, was synthesized as a chemosensor. The chemosensing capabilities of L were thoroughly investigated using fluorescence studies. The obtained results demonstrate that L effectively responds to the presence of zinc ions, leading to a significant increase in fluorescence intensity. Comparative studies were conducted to investigate the impact of various metal cations, including Cr(III), Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(I), Cu(II), Zn(II), Cd(II), Gd(III), Na(I), K(I), Ba(II), Mg(II), Al(III), Pb(II), Sn(II), Hg(II), and Ag(I), on the fluorescence of L in an aqueous ethanol environment. During our investigations, a binding constant value of 7.81 × 105 M⁻¹, with a 1:1 stoichiometry for Zn²⁺–L interactions, was established. Additionally, a low detection limit of 2.51 × 10⁻⁸ M and a rapid response time were observed. Furthermore, the chemical inputs of Zn²⁺ and Cu²⁺ ions meet the conditions of an INHIBIT molecular logic gate.