J. R. Kirchhoff, W. Heineman, E. Deutsch
Sep 1, 1987
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0
Influential Citations
33
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Journal
Inorganic Chemistry
Abstract
The redox properties of a series of rhenium(III) complexes with the general formula trans-(ReD/sub 2/X/sub 2/)/sup +/ (where D is one of the chelating phosphine or arsine ligands 1,2-bis(dimethylphosphino)ethane, 1,2-bis(diethylphosphino)ethane, 1,2-bis(diphenylphosphino)ethane, or 1,2-bis(dimethylarsino)benzene and X is Cl or Br) were investigated in 0.5 M TEAP/DMF by cyclic voltammetry, thin-layer electrochemistry, and thin-layer spectroelectrochemistry. The cationic trans-(ReD/sub 2/X/sub 2/)/sup +/ complexes exhibit a diffusion-controlled, reversible one-electron reduction to the neutral trans-(ReD/sub 2/X/sub 2/)/sup 0/ complexes at a platinum-disk electrode. The formal reduction potential, E/sup 0/', of the Re(III/II) redox couple ranges from -0.205 to 0.450 V vs Ag/AgCl (3 M NaCl). Further reduction to the rhenium(I) anion, trans-(ReD/sub 2/X/sub 2/)/sup -/, is possible; however, the reversibility of this process depends on the nature of the coordinating ligands and the experimental conditions. The Re(II/I) redox couple occurs at an E/sup 0/' value ca. 1.11 V more negative than that of the corresponding Re(III/II) couple. Thin-layer spectroelectrochemistry has been used to study the halogen-to-metal charge-transfer (HTMCT) band(s) of the Re(III) and Re(II) complexes. 36 references, 7 figures, 3 tables.