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

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 degrees 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 transitionmetal ions (Ni2+, Zn2+, Cd2+, Co2+, Cu2+, Fe3+, Cr3+/6+, Hg2+) and Pb2+, Ag+ did not interfere. The lowest detection limit for Al3+ was calculated to be 6.03 x 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.