Correlations between polarographic and spectroscopic parameters of some diacidotetramminerhodium (III) complexes

Cyclic Voltammetry and Chronocoulometry with trans-Rh(en)[sub 2]Cl[sub 2]+] at Mercury Electrodes

“…The concentration of (en) 2RhHg (OH) 2 +, determined spectrophotometrically (8) The foregoing results allow the oxidation wave appearing near --300 mV in Fig. This pH dependence could result from the pH dependence of equilibrium (2) that produces the Rh(en)~ + intermediate as well as from the direct involvement of hydroxide in the second stage of the oxidative electrode reaction (Reaction [6]). The same reactions are also presumed to account for the oxidation waves observed during the second, oxidative portion of the cyclic voltammograms of trans-Rh(en)2C12 + (Fig.…”

“…These voltammograms, Fig. 7 during an initially positive potential scan with alkaline solutions of Rh(en)2H(OH2) 2+ to be ascribed to reactions [5] and [6] occurring at potentials too close together to yield separate waves. Thus the reduction wave near --500 mV in Fig.…”

“…solutions [(en)2Rh]2Hg 4+ can be oxidized (reaction [6]) as well as reduced (reaction [8]). Figure 11 shows charge-(time)1/2 plots for the reduction reaction at several potentials.…”

“…As part of a study of the possible role of adsorbed transition metal complexes in the catalysis of electrode processes, we have been investigating the electrochemistry of some complexes of rhodium (IID because of their prominence as catalysts in homogeneous reactions (1,2). Previous polarographic and controlled potential electrolytic studies of various hexacoordinate chloroaminorhodium(III) complexes (3)(4)(5)(6) have established a common pattern of a single, two-electron reduction in which halide is liberated and tetracoordihate rhodium(I) complexes are produced. In the case of the trans-Rh (py)4C12 + complexes the polarographic behavior observed was taken to indicate that the rhodium(I) product was adsorbed on the mercury electrode (4).…”

Correlation Between Polarographic Half‐Wave Potentials and Electronic Spectra of Cis‐Trans Complexes of Chromium (III) and Rhodium (III)

“…The Eq. (7) then could be written as (8) If we take (E,/t) , and (EI/')' as the half-wave potential of cis and trans-(M(en).X 2 ) -+ isomers, respectively, we have and (EI/t),= ({1/naF)e,+ K;…”