A Fluorescent Chemosensor for Al3+ Based on CO 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 CO double bond in the excited state, however, after addition of Al3+, fluorescence emission results in a prominent fluorescence enhancement.