The photo- and electrophysical properties of curcumin in aqueous solution

An investigation of the photo- and electrophysical properties of curcumin (1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) revealed well-defined color changes upon the addition of Hg(2+) or OH(-). Curcumin exhibited high selectivity for Hg(2+) ions, as compared with Cu(2+), Fe(2+), Fe(3+), Zn(2+), Na(+) and Ni(2+) ions in DMSO/H(2)O (5:1, v/v) which was attributed to the formation of a 4:1 Hg(2+)-curcumin coordination complex. Spectral responses at lambda(max)=434nm revealed that curcumin can function as a NOR logic gate with OH(-) and Hg(2+) as input variables. The electrochromic properties of curcumin were studied using an ITO/curcumin-Bu(4)NClO(4)/ITO cell. The electrochromic cell colored red at 3V, but changed to yellow in open-circuit condition.