Singlet oxygen quenchers

Meta.1 Complexes. The importance of Ni complexes is based on their effectiveness as quenchers for singlet oxygen. Of disadvantage is their low colorfastness and their lower ir-reflectance compared to cyanine dyes (qv) therefore they are used in combination with suitable dyes. Numerous complexes are described in the Hterature, primarily tetrathiolate complexes of Pt or Ni, eg, dithiolatonickel complexes (3). Well known is the practical use of a combination of ben2othia2ole dyes with nickel thiol complexes in WORM disks (Ricoh, TDK) (17). 

Di Mascio, R, Kaiser, S., and Sies, H., Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch. Biochem. Biophys., 274, 532, 1989. Cantrell, A. et ah. Singlet oxygen quenching by dietary carotenoids in a model membrane environment. Arch. Biochem. Biophys., 412, 47, 2003. 

Although spironaphthooxazines have excellent lightfastness, they decompose slowly on exposure to sunlight. However, lightfastness can be improved by addition of nickel stabilizers (singlet oxygen quenchers) or hindered amines (antioxidants).86 88... 

The three unsymmetrical carotenoids have also been studied in methanol (Burke 2001) and all are very efficient singlet oxygen quenchers. This may be attributable to the polarity of the molecules. These asymmetrical XANs will possess a permanent dipole and their solvent interaction will... 

Di Mascio, P., S. Kaiser, and H. Sies. 1989. Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch Biochem Biophys 274(2) 532-538. 

Di Mascio P., Sandquist A., Devasagayam T., and Sies H. (1992). Assay of lycopene and other carotenoids as singlet oxygen quenchers. Methods Enzymol 213 429 438. 

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