Singlet oxygen generation from lophine hydroperoxides.

Singlet oxygen was detected from the reaction of lophine hydroperoxides 2 in the presence of 1,3-diphenyl-isobenzofuran as a singlet oxygen detector. In order to examine the substituent effect on the formation of (1)O(2), 2-(p-substituted phenyl) lophine peroxides 2a-c were tested. It was found that an electron-attracting group contributed to the efficient formation of (1)O(2) (80% for a NO(2) group), while an electron-donating group enhanced the efficiency of chemiluminescence.