In order to explore the effects of the structures of organic molecules on their performance and develop high-efficiency self-assembly monolayers (
SAMs), two heterocycle-based
indole compounds, namely FYBI and TYBI, have been synthesized by a simple route. Herein, we show that FYBI and TYBI can effectively self-assemble on a
copper surface and form strong anti-
corrosive monolayers to protect
copper in
acid medium. The compositions, morphologies, and thicknesses of the
SAMs have been investigated by XPS, FTIR, SEM and ellipsometry analyses. The optimal self-assembly conditions and inhibition performance of the
SAMs with O- or S-heterocycles have been studied by electrochemical tests. According to the results, TYBI displays more powerful inhibition performance than FYBI. Furthermore, the high-resolution XPS and quantum calculation results reveal that the S-heterocycle
indole (TYBI) can readily donate electrons to the empty d orbital of Cu and form more robust, hydrophobic, and anti-
corrosive SAMs than the O-heterocycle
indole (FYBI). The inhibited corrosion is achieved by inhibiting the generation of Cu2+. This systematic study on the performance of various heterocycle-based organic compounds gives a fresh perspective for forming
SAMs with certain characteristics, such as anti-corrosion ability or super-hydrophobicity.