title: Electrochemical reactions at a porphyrin-copper interface.
abstract: The structure and reactivity of a Cu(100) single crystal electrode surface covered with free base meso-tetra (N-methyl-4-pyridinium) porphyrin (abbreviated as H(2)TMPyP) as a function of electrode potential have been investigated with cyclic voltammetry (CV), electrochemical scanning tunneling microscopy (ECSTM), and UV-Vis and Raman spectroscopy. The well-ordered self-assembled layer of the porphyrin is consistent with the adsorption of the reduced porphyrin species after the first two-electron reduction step. The copper dissolution reaction in the presence of the stable self-assembled porphyrin layer starts at step edges on both upper and lower terraces and coincides with the preferential oxidation of reduced porphyrin species at step sites. The dissolved copper cations are incorporated into the free base porphyrin molecules leading to the formation of CuTMPyP. As a consequence this new species accumulates in the solution with time and a copper redeposition in the cathodic potential scan is lacking.
authors: Institute for Physical and Theoretical Chemistry, University of Bonn, Wegeler Str. 12, D-53115 Bonn, Germany.
authors: Nguyen T M
authors: NT
authors: Hai
authors: Shuhei
authors: S
authors: Furukawa
authors: Tom
authors: T
authors: Vosch
authors: Steven
authors: S
authors: De Feyter
authors: Peter
authors: P
authors: Broekmann
authors: Klaus
authors: K
authors: Wandelt
mesh_terms: D003300:Copper / Q000737:chemistry*; D004563:Electrochemistry; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D011166:Porphyrins; D003300:Copper