Mechanism of the chromium(2+), vanadium(2+), and hexaammineruthenium(2+) reduction of N-bonded glycinato- and .beta.-alaninatopentaamminecobalt(III) complexes. Evidence for paths involving precursor complex formation with outer-sphere electron transfer

Thermal intramolecular cobalt(III)-iron(II) and cobalt(III)-titanium(III) electron-transfer reactions involving outer-sphere and inner-sphere precursor complexes

“…No direct interaction of the first coordination spheres of the reacting metal ions can occur. 24,25 The most important point of this study is the fact that the reducing power of the reductants (Fe(II) or Ti(III)) can be varied (this is achieved by the formation of 1:1 and 2:1 complexes, respectively), and, independently, the oxidizing ability of the Co(III) centers can be varied (by changing the nonbridging ligands at the cobalt(III) ions), but the structural details between the reactants remain unchanged.…”

“…Intramolecular ET reactions between two metal ions can proceed without an "orbital-coupling mechanism" through the bridging ligand which in this case serves only to bring the reacting centers in close proximity. 24,25 In other words, the bridging ligand may not supply the energetically most favorable route for the ET process. It exhibits all the characteristics of an outer-sphere ET reaction.…”