Electrochemical and in situ spectroelectrochemical behavior of 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H(2)OHTTAP) and (Zn(II)OHTTAP)

The characterization of free base porphyrin 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H(2)OHTTAP) and its zinc(II) complexes [Zn(II)OHTTAP] containing eight thioether groups at the beta -pyrrole positions of the macrocycle was reported. Results obtained by cyclic voltammetry and differential pulse voltammetry indicated a five-electron reduction in five steps for each complex. They were oxidized in two single-electron-transfer steps to yield pi -cation radicals and dications and reduced in three single-electron-transfer steps to yield pi -anion radicals, dianions and trianions, respectively. The redox property of H(2)OHTTAP was unusual as compared to porphyrins (PPs) and phthalocyanines (Pcs). Each process was monitored by in situ thin-layer spectroelectrochemistry, which indicated that only the Ligand was electroactive. The existence of the eight hexylthio groups was responsible for the intrastack interactions and enhanced intracolumnar and intercolumnar electron motions, resulting in improved conductivity. Copyright (C) 2001 John Wiley & Sons, Ltd.