THE ELECTROCHEMICAL PROPERTIES OF THE (MU-ETA-6,ETA-6-NAPHTHALENE)DICHROMIUM COMPOUNDS AND BIS(ETA-6-NAPHTHALENE)CHROMIUM

The electrochemistry of the novel macromolecular organometallic polymer poly[(μ-η6,η6-naphthalene)chromium] is delineated through the study of its precursor (bis(η6-naphthalene)chromium) and an oligomeric model ((μ-η6,η6-naphthalene)bis(η6-benzene)dichromium) in order to observe the degree of intervalence charge transfer between chromium sites in the multinuclear species. Theoretical studies have indicated that the multidecker sandwich compound poly[(μ-η6,η6-naphthalene)chromium] should be an electrical conductor in its oxidized state; no electrical conductivity is observed in the zero valent state. The inferred mechanism of the ligand exchange process of bis(η6-naphthalene)chromium in tetrahydrofuran through an η2-THF, η4,η6 intermediate is supported by the CE mechanism of the Cr 0 + couples observed by the Nicholson and Shain method of kinetic analysis in (μ-η6,η6-naphthalene)bis(η6-benzene)dichromium). The cyclic voltammetry of bis(η6-naphthalene)chromium and (μ-η6,η6-naphthalene)bis(η6-benzene)dichromium) in tetrahydrofuran, and bis(η6-naphthalene)-chromium and poly[(μ-η6,η6-naphthalene)chromium] in ethylenediamine are described to delineate the electrochemical behavior of chromium compounds incorporating η6-naphthalene and μ-η6,η6-naphthalene moieties. In addition to the various kinetic processes, characteristic Cr 0 + and relatively unusual Cr + 2+ couples were observed; ligand (naphthalene)(0/-) and ( - 2-) redox couples were also observed. While the second reduction of the μ-η6,η6-naphthalene moiety was inhibited by the first reduction, mixed valence interaction between the metal sites was not observed electrochemically. © 1990.