%0 Journal Article %1 Kaim.2003b %A Kaim, Wolfgang %A Reinhardt, Ralf %A Greulich, Stefan %A Fiedler, Jan. %D 2003 %J Organometallics %K ESR;rhodium UV azobispyridine complex electrochem intermediate iridium prepn radical redox rhodium spectroelectrochem %N 11 %P 2240--2244 %R 10.1021/om020860j %T Resolving the Two-Electron Process for the Couple (C5Me5)M(NN̂)Cl+/(C5Me5)M(NN̂) (M = Rh, Ir) into Two One-Electron Steps Using the 2,2'-Azobis(pyridine) NN̂ Ligand, Fast Scan Cyclovoltammetry, and Spectroelectrochemistry: Detection of Radicals instead of MII Intermediates %V 22 %X (C5Me5)M(abpy)Cl+ M = Rh, Ir; abpy = 2,2'-azobis(pyridine) are reduced to the coordinatively unsatd. compds. (C5Me5)M(abpy) via the EPR and UV/visible spectroelectrochem. detectable radical intermediates (C5Me5)MIII(abpy-I)Cl.bul.. Fast-scan cyclic voltammetry allowed the authors to establish the electrochem. potentials. This stepwise mechanism differs from the two-electron processes obsd. for the analogous systems (C5Me5)M(NN̂)Cl+/(C5Me5)M(NN̂) with NN̂ = 2,2'-bipyridines, bidiazines, 1,4-diaza-1,3-butadienes. In contrast to Co systems such as (C5Me5)Co(bpy)Cl+ the 1-electron redn. does not involve the metal. The role of the abpy ligand as an intermediate 1-electron storage component for a metal-centered two-electron process is discussed. Further redn. of (C5Me5)M(abpy) to (C5Me5)MII(abpy-II)- at very neg. potentials illustrates the extremely strong p back-donation from the 14-valence-electron fragments (C5Me5)M (M = Rh, Ir). on SciFinder(R)

@article{Kaim.2003b, abstract = {[(C5Me5)M(abpy)Cl]+ [M = Rh, Ir; abpy = 2,2'-azobis(pyridine)] are reduced to the coordinatively unsatd. compds. [(C5Me5)M(abpy)] via the EPR and UV/visible spectroelectrochem. detectable radical intermediates [(C5Me5)MIII(abpy-I)Cl].bul.. Fast-scan cyclic voltammetry allowed the authors to establish the electrochem. potentials. This stepwise mechanism differs from the two-electron processes obsd. for the analogous systems [(C5Me5)M(NN̂)Cl]+/[(C5Me5)M(NN̂)] with NN̂ = 2,2'-bipyridines, bidiazines, 1,4-diaza-1,3-butadienes. In contrast to Co systems such as [(C5Me5)Co(bpy)Cl]+ the 1-electron redn. does not involve the metal. The role of the abpy ligand as an intermediate 1-electron storage component for a metal-centered two-electron process is discussed. Further redn. of [(C5Me5)M(abpy)] to [(C5Me5)MII(abpy-II)]- at very neg. potentials illustrates the extremely strong \textgreek{p} back-donation from the 14-valence-electron fragments (C5Me5)M (M = Rh, Ir). [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Kaim, Wolfgang and Reinhardt, Ralf and Greulich, Stefan and Fiedler, Jan.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/245fada6ab064c52ad120e777e101d15d/huebleriac}, doi = {10.1021/om020860j}, interhash = {daba6141d9898aaba4ea1beaa2a08061}, intrahash = {45fada6ab064c52ad120e777e101d15d}, issn = {0276-7333}, journal = {Organometallics}, keywords = {ESR;rhodium UV azobispyridine complex electrochem intermediate iridium prepn radical redox rhodium spectroelectrochem}, number = 11, pages = {2240--2244}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Resolving the Two-Electron Process for the Couple [(C5Me5)M(NN̂)Cl]+/[(C5Me5)M(NN̂)] (M = Rh, Ir) into Two One-Electron Steps Using the 2,2'-Azobis(pyridine) NN̂ Ligand, Fast Scan Cyclovoltammetry, and Spectroelectrochemistry: Detection of Radicals instead of MII Intermediates}, volume = 22, year = 2003 }