Spectroelectrochemical Studies of Metallophthalocyanines Adsorbed on Electrode Surfaces

Co(II)‐ and Fe(II)‐phthalocyanines adsorbed on platinum and various carbon electrode surfaces have been studied by spectroelectrochemical techniques. The metallophthalocyanine (MPc) films were prepared on substrate electrodes by a drop‐dry method after dissolving them in pyridine. While not much change in the spectroscopic properties is observed for MPcs adsorbed at the platinum electrode, both the Soret and Q bands were significantly broadened when adsorbed on the carbon electrodes. Also, the metal‐ligand charge‐transfer (MLCT) bands are observed from films adsorbed on carbon substrates even if they are not reduced. These observations lead to the conclusion that the MPc molecules not only undergo oligomerization but also interact strongly with carbon surfaces by perhaps sharing the π‐electrons of carbon.