extraordinary narrow voltammetry signals

Author: lasha laliashvili
Keywords: charge, peak
Annotation:

Our scientific group’s aim is to study the mechanism of processes that take place in the biological and model (biomimetic) systems at the atomistic level. This presentation describes experimental disclosure of an unusual electron exchange phenomenon occurring between the Cu2+ ions immobilized within the gold deposited L-cysteine self assembled monolayers (SAMs), on the one hand, and the supporting gold electrode itself, on another. The current nanometer-thick composite systems may be considered as the models of the redox-active globular proteins containing single or several copper ions such as laccase, azurin, ceruloplasmin etc. According to the experimental data published by various authors, which were obtained, in particular, by the cyclic voltammetric method, electron exchange involving the Cu2+ ions and gold electrode occurs through the single electron transfer (n = 1) mechanism, in which there is no electronic correlation among the Cu2+ ions, hence they participate in a statistically independent manner throughout the whole process. Our studies revealed, that among the L-cysteine immobilized copper ions some interaction may emerge at the high surface concentration of the Cu2+ ions, presumably leading to the formation of two-dimensional nanometer-thick clusters of Cu2+ centers acting as a single entity. Hence, numerous electrons (e.g., n = 2, 4, 6, 10, etc.) may be transferred synchronously. The overall phenomenon shows up as a transformation of the single electron voltammetric signal (broad peaks) into multi electron voltammetric signal (narrow peaks). Furthermore, as the overall number of the immobilized redox-active Cu2+ ions does not change, the concentration of the active multi electron clusters are inversely proportional to the number of the synchronously transferred electrons.