The adsorption of corypalline and related compounds on a pyrolytic graphite electrode

Anodic current-time curves have been used to study the adsorption, from TEAP-acetonitrile solution, of corypalline (7-hydroxy-6-methoxy-N-methyl-1,2,3,4-tetrahydroisoquinoline), isocorypalline (6-hydroxy-7-methoxy-N-methyl-1,2,3,4-tetrahydroisoquinoline), and 1-methyl-corypalline. A comparison with analogous cathodic current-time curves obtained with methylene blue leads to the conclusion that, on a pyrolytic graphite electrode, these isoquinoline compounds are adsorbed in a “flat-on” configuration. This conclusion is in harmony with the postulation that the known steroselective, stereospecific oxidative coupling of 1-methylcorypal-line occurs through the adsorption of the reacting molecules on the electrode surface.