Supramolecular carriers of singlet oxygen:: Photosensitized formation and thermal decomposition of endoperoxides in the presence of cyclodextrins

Water-soluble 2,7-disulfonato-9,10-diphenylanthracene (2,7-dsDPA) and 2,6-disulfonato-9,10-diphenylanthracene (2,6-dsDPA) react with singlet oxygen O-2((1)Delta(g)) produced by photosensitized reaction and form thermostable endoperoxides. The thermal decomposition of endoperoxides at higher temperatures (60-150 degrees C) leads to the production of O-2((1)Delta(g)). 2,7-dsDPA, 2,6-dsDPA and corresponding endoperoxides 2,7-dsDPAO(2), 2,6-dsDPAO(2) form 1:1 host-guest complexes with native cyclodextrins (CDs) and 2-hydroxypropylated cyclodextrins (hpCDs). The binding constants (10(2)-10(4) M-1) depend on the cavity size and the functionalization of the primary face of CDs. The thermal stabilities of both endoperoxides in host-guest complexes with CDs and hpCDs are highly increased. (C) 2007 Elsevier B.V. All rights reserved.