Studies on curcumin and curcuminoids. XLVI. Photophysical properties of dimethoxycurcumin and bis-dehydroxycurcumin

The steady-state absorption and fluorescence, as well as the time-resolved fluorescence properties of dimethoxycurcumin and bis-dehydroxycurcumin dissolved in several solvents differing in polarity and H-bonding capability are presented. The singlet oxygen generation efficiency of the two compounds relative to curcumin is estimated. The photodegradation quantum yield of the former compound in acetonitrile and methanol is determined. The dimethoxycurcumin and bis-dehydroxycurcumin decay mechanisms from the S1 state are discussed and compared with those of curcumin, dicinnamoylmethane and bis-demethoxycurcumin. © Springer Science+Business Media, LLC 2011.