Jump to main content
Jump to site search

Issue 12, 2012
Previous Article Next Article

Surface-enhanced Raman scattering of 4,4′-dimercaptoazobenzene trapped in Au nanogaps

Author affiliations

Abstract

The surface-enhanced Raman scattering (SERS) of 4,4′-dimercaptoazobenzene (4,4′-DMAB), an alpha, omega-dithiol possessing also an azo moiety, has seen a surge of interest recently, since 4,4′-DMAB might be able to form from 4-aminobenzenethiol (4-ABT) via a surface-induced photoreaction. An understanding of the intrinsic SERS characteristics of 4,4′-DMAB is thus very important to evaluate the possibility of such a photoreaction. We found in this work that 4,4′-DMAB should adsorb on a flame-annealed Au substrate via one of its two thiol groups such that Au nanoparticles could adsorb further on the pendent thiol group, forming a SERS hot site. The most distinctive feature in the SERS of 4,4′-DMAB was the appearance of ag bands, which were quite similar to the b2-type bands occurring in the SERS of 4-ABT. In an electrochemical environment, the ag bands of 4,4′-DMAB at 1431, 1387, and 1138 cm−1 became weakened at lower potentials, completely disappearing at −1.0 V, but the bands were restored upon increasing the electrode potential, implying that neither electro- nor photo-chemical reaction to break the azo group took place, in agreement with data from a cyclic voltammogram. The appearance and disappearance of these ag bands are thus concluded to be associated with the charge transfer phenomenon: 4,4′-DMAB must then be one of a unique group of compounds exhibiting chemical enhancement when subjected to a SERS environment.

Graphical abstract: Surface-enhanced Raman scattering of 4,4′-dimercaptoazobenzene trapped in Au nanogaps

Back to tab navigation

Supplementary files

Article information


Submitted
29 Dec 2011
Accepted
31 Jan 2012
First published
14 Feb 2012

Phys. Chem. Chem. Phys., 2012,14, 4095-4100
Article type
Paper

Surface-enhanced Raman scattering of 4,4′-dimercaptoazobenzene trapped in Au nanogaps

K. Kim, D. Shin, K. L. Kim and K. S. Shin, Phys. Chem. Chem. Phys., 2012, 14, 4095
DOI: 10.1039/C2CP24135H

Social activity

Search articles by author

Spotlight

Advertisements