Characterization of Coordination Compounds by Electrochemical Parameters

Abstract

Attention is drawn to the interest in the use of the redox potential for the characterization and identification of coordination compounds on the basis of redox potential-structure relationships that define electrochemical parameters, which are shown for a wide variety of ligands and metal sites.

C-Homoscorpionate Oxidation Catalysts—Electrochemical and Catalytic Activity

“…The hardest to reduce (−0.11 V vs. SCE, Table 1) yields only 7.5% of the oxygenated mixture under the same conditions [64]. The lower reduction potential of [AuCl 2 {κ 2 -HC(3,5-Me 2 pz) 3 }]Cl in comparison with the one of [AuCl 2 {κ 2 -HC(pz) 3 }]Cl is consistent with the stronger electron-donor ability of the methyl-substituted κ 2 -HC(3,5-Me 2 pz) 3 ligand than that of κ 2 -HC(pz) 3 [24]. However, an accurate comparison cannot be established due to the irreversibility of the reduction waves (the reduction potential is not the thermodynamic one).…”

“…In the case of Mo(0 or II) complexes a second single-electron oxidation process is detected (not shown in Table 1 3 ] signals the instability of the resulting cationic Mo(III) complexes, which then rapidly decompose with probable CO loss [95] and, for the hydride compound, by deprotonation [96][97][98]. The first oxidation potentials of all these tricarbonyl complexes are much lower than that of the parent hexacarbonyl compound, on account of the replacement of three carbonyls in the latter by the more electron-donating C-scorpionate ligands [24,27,28]. Moreover, the first oxidation potential of [MoH{κ 3 -SO 3 C(pz) 3 }(CO) 3 ] in comparison with [MoI{κ 3 -SO 3 C(pz) 3 }(CO) 3 ] reflects the stronger electron-donor character of the hydride relatively to the iodide ligand [28].…”

Molybdenum Complexes Bearing the Tris(1‐pyrazolyl)methanesulfonate Ligand: Synthesis, Characterization and Electrochemical Behaviour

“…[62][63][64][65] The first oxidation potentials of all these tricarbonyl complexes are much lower than that of the parent hexacarbonyl compound (0.98 V vs Fc/Fc + ) on account of the replacement of three carbonyl groups in the latter by other more electron-donating ligands. [66][67][68][69] The lower first oxidation potential of 5 in comparison with 3 reflects the stronger electron-donor character of the hydride relatively to the iodide ligand. [68] The first oxidation potential of the Mo 0 complex 1 (-0.…”

“…[68] The first oxidation potential of the Mo 0 complex 1 (-0. 35 3 ] n , in which L is a tridentate N-donor ligand [Tp (n = -1), [70] Tpm Me (n = 0), [71] 1,4,7-trimethyl-1,4,7-triazacyclononane (n = 0), [72] or 1,4,7-tribenzyl-1,4,7-triazacyclononane (n = 0)], [70] thus reflecting [66][67][68][73][74][75] the relative donor/acceptor abilities of these different L ligands. The more negative value (-0.53 V vs Fc/Fc + ) is reported [70] 3 ], [71] whereas that of 1 is intermediate, in accord with the order of the net electron-donor ability of the corresponding tripodal ligands.…”

Negatively Charged Metallacarborane Redox Couples with Both Members Stable to Air

“…Recently, [17] based on seminal works of Pombeiro, [18] Pickett, [19] Lever, [20] and Bursten [21] groups, reviewed on the importance of establishing ar elationship between the redox potential structure of complexes that define electrochemical parameters, which are shown for aw idev arietyo fl igandsa nd metal sites. Lever and co-workersr eported [20] an electrochemical parametrization in sandwich complexes of the first-row transition metals can be established by assigning electrochemical parameters to the ligands.…”