A Fluorescent Chemosensor for Al3+ Based on CO Isomerization Derivated from Curcumin

A simple and nontoxic fluorescent chemosensor of di‐O‐methyl curcumin has been prepared from curcumin. The sensor exhibited selective and sensitive fluorescent responses toward Al³⁺ over a wide range of metal ions, such as Mn²⁺, Ce³⁺, Pt²⁺, Sn⁴⁺, Hg⁺, Sb³⁺, K⁺, Ca²⁺, Mg²⁺, Ba²⁺, Cu²⁺, Ni²⁺, Na⁺, NH₄⁺, Ag⁺, Pb²⁺, Zn²⁺, Fe²⁺, Fe³⁺, Hg²⁺ and Cr³⁺ in ethanol/water. The free ligand showed quite weak fluorescence emission due to the isomerization of C?O double bond in the excited state, however, after addition of Al³⁺, fluorescence emission results in a prominent fluorescence enhancement.