Phenolate and phenoxyl radical complexes of Co(II) and Co(III)

Laurent Benisvy, Eckhard Bill, Alexander J. Blake, David Collison, E. Stephen Davies, C. David Garner, Christina I. Guindy, Eric J.L. McInnes, Graeme McArdle, Jonathan McMaster, Claire Wilson, Joanna Wolowska

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


The new phenol-imidazole pro-ligands RLH react with Co(BF 4)2·6H2O in the presence of Et 3N to form the corresponding [CoII(RL) 2] compound (R = Ph (1), PhOMe (2), or Bz (3)). Also, BzLH, reacts with Co(II) in the presence of Et3N and H2O2 to form [CoIII(BzL) 3] (4). The structures of l·2.5MeCN, 2·2DMF, 3·4MeOH, and 4·4DMF have been determined by X-ray crystallography. 1, 2, and 3 each involve Co(II) bound to two N,O-bidentate ligands with a distorted tetrahedral coordination sphere; 4 involves Co(III) bound to three N,O-bidentate ligands in a mer-N3O3 distorted octahedral geometry. [CoII(RL)2] (R = Ph or PhOMe) undergo two, one-electron, oxidations. The products of the first oxidation, [1] + and [2]+, have been synthesised by the chemical oxidation of 1 and 2, respectively; these cations, formulated as [Co II(RL)(RL)2]+, comprise one phenoxyl radical and one phenolate ligand bound to Co(II) and are the first phenoxyl radical ligand complexes of tetra-coordinated Co(II). 4 undergoes two, one-electron, ligand-based oxidations, the first of which produces [4] +, [CoIII(BzL)(BzL)2]+. Unlike [l]+and [2]+, product of the one-electron oxidation of [CoII(BzL)2], [3]+, is unstable and decomposes to produce [4]+. These studies have demonstrated that the chemical properties of [MII(RL)(RL) 2]+ (M = Co, Cu, Zn) are highly dependent on the nature of both the ligand and the metal centre.

Original languageEnglish
Pages (from-to)3647-3653
Number of pages7
JournalDalton Transactions
Issue number21
StatePublished - 7 Nov 2004
Externally publishedYes


Dive into the research topics of 'Phenolate and phenoxyl radical complexes of Co(II) and Co(III)'. Together they form a unique fingerprint.

Cite this