Modification of nanostructured gold surfaces with organic functional groups using electrochemical and solid-phase synthesis methodologies

Anthraquinone and nitrobenzene redox probes were covalently attached to nanostructured sphere segment void (SSV) gold substrates prepared using templated electrodeposition. Anthraquinone was attached to the SSV gold surface through an (aminomethyl)phenyl (NH2CH2C6H4) linker using a combination of electrochemical coupling and solid-phase modification. The nitrobenzene probe was directly immobilized by electrochemical reduction of the corresponding diazonium salt or by self-assembly of 4-nitrobenzene thiol. The surface coverages and stabilities of the modified gold surfaces were characterised by electrochemical and surface enhanced Raman scattering (SERS) techniques. The results demonstrate that electrochemical coupling followed by solid phase coupling is a flexible method for the functionalisation of nanostructured SSV, or other, gold surfaces. The use of the SSV gold substrate allows us to follow the different steps in the modification process using SERS. We find that that diazonium attachment to gold gives greater stability than the more commonly used thiol self-assembly approach.

► Diazonium coupling of a Boc protected amine followed by solid phase coupling chemistry can be used to modify gold electrodes. ► The coupling and modification reactions can be followed by SERS using sphere segment void (SSV) gold electrodes. ► The diazo coupling to gold yields surfaces which are more stable than the corresponding thiol modified surfaces.