Reactivity of hydrogenated diamond surface with radical initiators generating organic oxygen radical species

Reactivity of hydrogenated diamond surface was investigated with peroxide radical initiators. The radical initiators used in this study were diacyl peroxide (R-COO-OOC-R) and dialkyl peroxide (R₃CO-OCR₃). Hydrogen abstraction reaction of hydrogenated diamond surface was attempted in liquid phase using these radical initiators. The radical species generated from diacyl peroxide such as benzoyl peroxide and lauroyl peroxide could extract the hydrogen atoms from the diamond surface, regardless of the kind of solvent. From the results of the spectra, we presume that the functional group is related to the radical species introduced on the diamond surface. On the other hand, the radical species generated from dialkyl peroxide such as di-t-butyl peroxide and dicumyl peroxide did not fully extract the hydrogen atoms from the diamond surface, regardless of the kind of solvent. Although oxygen radicals are generated from both diacyl peroxide and dialkyl peroxide, the molecular structure of the generated radical species is different for each radical species. The radical species generated from diacyl peroxide is R-COO·, and the radical species generated from dialkyl peroxide is R₃CO·. It was revealed that the reactivity of hydrogenated diamond surface with radical species depended not on the functional group in the radical initiator but on the molecular structure of the generated radical species.