A water soluble Al3+ selective colorimetric and fluorescent turn-on chemosensor and its application in living cell imaging

Abstract

An efficient water soluble fluorescent Al³⁺ receptor, 1-[[(2-furanylmethyl)imino]methyl]-2-naphthol (1-H) was synthesized and characterized by physico-chemical and spectroscopic tools along with single crystal X-ray crystallography. High selectivity and affinity of 1-H towards Al³⁺ in HEPES buffer (DMSO/water: 1/100) of pH 7.4 at 25 °C showed it to be suitable for detection of intracellular Al³⁺ by fluorescence microscopy. Metal ions, viz. alkali (Na⁺, K⁺), alkaline earth (Mg²⁺, Ca²⁺), and transition-metal ions (Ni²⁺, Zn²⁺, Cd²⁺, Co²⁺, Cu²⁺, Fe³⁺, Cr^3+/6+, Hg²⁺) and Pb²⁺, Ag⁺ did not interfere. The lowest detection limit for Al³⁺ was calculated to be 6.03 × 10⁻⁷ M in 100 mM HEPES buffer (DMSO/water: 1/100). Theoretical calculations have also been included in support of the configuration of the probe–aluminium complex.