Potential-controlled coordination of columarin to an Au(210) electrode surface

Adsorption of coumarin on an Au(210) single-crystal electrode was investigated using chronocoulometry and phase-sensitive a.c. voltammetry. The adsorption parameters, such as the relative Gibbs surface excess, the Gibbs energies of adsorption and the electrosorption valencies, were calculated. The results suggest that coumarin molecules assume a flat, pi-bonded orientation on the Au(210) surface. The zero coverage Gibbs energy of adsorption at the potential of maximum adsorption is -42 kJ mol(-1), which is a value typical of chemisorption. The adsorption of coumarin on the Au(210) surface was compared with adsorption at the (111) and (100) planes of gold. Copyright (C) 2003 John Wiley Sons, Ltd.