In-situ Spectroscopic Studies of Redox Active Self-Assembled Monolayers on GoldElectrode Surfaces

摘要

Monolayers of N-ethyl-N-octadecyl-4,4-bipyridinium (EOB) have been prepared onsmooth gold surfaces prepared by spontaneous self-assembly of the electrochemically reduced form of the amphiphile and have been examined with in situ Fourier Transform Infrared Reflection Absorption Spectroscopy (FTIRRAS). Prominent positive-going peaks with hardly any detectable negative-going counterparts were observed in the normalized potential difference spectra of the layer in the reduced state (using as a reference the spectra for the layer in the fully oxidized state) in the region between 1100 and 1700 cm-1. In analogy with a model put forward by other workers it is proposed that the spectral bands originate from vibronically activated totally symmetric modes of EOB+ in monomeric and/or dimeric form.