Introduction of molecules containing a NO 2 group on diamond surface by using radical reaction in liquid phase

Abstract

Chemical reaction of hydrogenated diamond surface with nitrobenzoic acid (NO 2-C 6H 4-COOH) and the radical species was investigated. The IR peak assigned to the NO 2 group appeared after the reaction process. The peak intensity of the NO 2 group depended on the steric structure of the reacted nitrobenzoic acid. The NO 2 peak intensity of the diamond reacted with p-nitrobenzoic acid is much smaller than that of the diamond reacted with o-, or m-nitrobenzoic acid. In this study, 3,4-dinitorobenzoic acid or 3,5-dinitorobenzoic acid was also used. The IR spectra for the diamond treated with 3,4-dinitorobenzoic acid were unclear. On the other hand, the IR spectra for the diamond treated with 3,5-dinitorobenzoic acid showed the peak assigned to the NO 2 group. From the experimental results, we may assume that the NO 2 group at para-position against the COOH group hindered the reaction of the COOH group with diamond surface. The NO 2 peak intensity for the diamond treated with 3,5-dinitorobenzoic acid was comparable with that for the diamond treated with o- or m-nitrobenzoic acid. These results should means that the amount of the NO 2 group introduced on diamond surface was comparable. The introduction of NO 2 group on diamond surface was realized by the method applied in this study.