Light-induced O₂-dependent aliphatic carbon–carbon (C–C) bond cleavage in bipyridine-ligated Co(ii) chlorodiketonate complexes

Abstract

Illumination of aerobic acetonitrile solutions of bipyridine-ligated Co(ii) chlorodiketonate complexes results in O2-dependent aliphatic C–C bond cleavage with high 18O incorporation.

Chelated O2BOH2– or Chelated O2CO2–: An Isoelectronic Conundrum

“…A Co(III) oxidation state was further supported by examination of the reported X-ray structure; the Co−N bond lengths, which range from 1.913 to 1.944 Å, are consistent with those found in Co(III) complexes containing two bipy ligands 17,18 and are significantly shorter than those in analogous Co(II) complexes (d Co−N ∼ 2.1 Å). 19,20 Similarly, the reported B−O bond lengths are almost exactly the same as the C−O distances found in Co(III) amine complexes containing chelated carbonate. 4,7,10 Finally, we were concerned about the presence of an H 3 O + ion in the structure.…”

“…First, the reaction was carried out under aerobic conditions; air oxidation of solutions of Co­(II) in the presence of amine ligands is often facile, and while Co­(II) complexes containing two bipy ligands have been isolated under aerobic conditions, , oxidation to Co­(III) cannot be excluded. A Co­(III) oxidation state was further supported by examination of the reported X-ray structure; the Co–N bond lengths, which range from 1.913 to 1.944 Å, are consistent with those found in Co­(III) complexes containing two bipy ligands , and are significantly shorter than those in analogous Co­(II) complexes ( d Co–N ∼ 2.1 Å). , Similarly, the reported B–O bond lengths are almost exactly the same as the C–O distances found in Co­(III) amine complexes containing chelated carbonate. ,, Finally, we were concerned about the presence of an H 3 O + ion in the structure. The complex was prepared under basic conditions (pH ∼ 9), and we believed it extremely unlikely that a hydronium ion of crystallization would be obtained from such an environment .…”