摘要:
Electrochemical and spectroelectrochemical data for (Cp)Ti(L) and (Cp*)Ti(L), where Cp is the anion of cyclopentadienyl and Cp* is the anion of pentamethylcyclopentadienyl and L is either cyclooctatetraene (C8H8) or the tropylium ion (C7H7+) are presented in this paper. The electrochemical properties of complexes 1-4 [(Cp)Ti(L) L = C8H8 (1), C7H7 (2); (Cp*)Ti(L), L = C8H8 (3), C7H7 (4)] are shown to be dependent upon the electron-donating ability of L and the solvent-supporting electrolyte system. Complexes 2 and 4 can be reduced and oxidized by one electron, while complexes 1 and 3 only exhibit a one-electron oxidation. The presence of perchlorate anion, from the supporting electrolyte, strongly affects the electrochemical response for complexes 1 and 3 but not complexes 2 and 4. The synthesis of (Cp*)Ti(C8H8)(ClO4) is described, and this species is characterized by H-1 NMR, infrared, and electronic spectra and by electrochemical methods. An electron-transfer mechanism for complexes 1-4 is presented, and the use of spectroelectrochemical methods to examine the site of electron transfer for this set of organometallic species is discussed.