Generation of surface-confined catechol terminated SAMs via electrochemically triggered Michael addition: characterization, electrochemistry and complex with Ni(ii) and Cu(ii) cations

Abstract

In this paper, catechol, 1,4-dihydroxybenzene and dopamine are investigated as precursors of electrophiles for Michael addition reaction with the self-assembled monolayer (SAM) of 4-thiouracil (4-TU) via electrochemical triggering. All compounds can undergo Michael addition reaction with 4-TU; however, only catechol can react with 4-TU with high efficiency. The catechol-terminated SAMs, via electrochemically triggered Michael addition reaction, exhibit reversible redox response. In addition, we find that catechol-terminated SAMs can complex with Ni²⁺ and Cu²⁺ with different electrochemical behaviors. Moreover, the mechanism of complexation of Ni²⁺and Cu²⁺ with catechol-terminated SAMs is also demonstrated with electrochemical and spectrometric methods. Based on the different electrochemical behaviors of Cu²⁺ and Ni²⁺ complex, the catechol-terminated SAMs provide a potential platform for metal ions recognition.