A highly specific 'turn-on' fluorescent detection of Mg2+ through a xanthene based fluorescent molecular probe

摘要

Two acid hydrazones incorporating xanthene as a metal chelating centre (B-XAN and N-XAN) have been synthesized, characterized and evaluated for the optical sensing of Mg2+ and Al3+. The replacement of the naphthyl moiety in N-XAN by the phenyl moiety in B-XAN leads to total specificity of the latter one towards Mg2+. The B-XAN exhibited a highly sensitive and selective 'turn-on' fluorescent response towards Mg2+ through intense blue fluorescence enhancement. This measurement was free from any interference by other cationic analytes including the Ca2+ and Al3+ also. The binding constant, stoichiometry as well as the mechanistic aspect of the above sensing phenomenon were also studied through various spectroscopic methods.