Tris(polypyridine)nickel(II) complexes: Synthesis, DFT and electrochemistry

Stereochemical Control of Redox CoII/CoIII-Cages with Switchable Cotton Effects Based on Labile-Static States

“…After careful screening of oxidants and reductants appropriate for reversible redox processes, we selected the simple hydrogen peroxide (H 2 O 2 ) as an oxidant, which can smoothly achieve the oxidation of divalent metalloligands and the Co II 8 Pd 6 cage under mild conditions (Figures 3a and S42 To further confirm the cage integrity during this reduction process, H 2 O 2 was successively added to the above solution, leading to the oxidation of the Co II -centers back to the trivalent form without structural dissociation. For comparison, the Fe II 8 Pd 6 and Ni II 8 Pd 6 isomorphic cages could not undergo similar redox transformation under such mild redox conditions due to the higher redox potentials of the polypyridyl Fe II -and Ni IIcenters, 70,77 highlighting the advantage of Co-centers in achieving valence transitions under mild conditions (Figures S51 and S52). Long-term stability tests showed that oxygen can also act as an oxidant to slowly oxidize Co II 8 Pd 6 partially into Co III 8 Pd 6 after its solution was placed in the air for 2 months.…”