Reactivity of a cobalt(III)-peroxo complex in oxidative nucleophilic reactions

Jo, Young-Rae; Annaraj, Jamespandi; Seo, Mi Sook; Lee, Yong Min; Kim, Sung Yeon; Cho, Jaeheung; Nam, Wonwoo

doi:10.1016/j.jinorgbio.2008.08.008

Cited by 61 publications

(46 citation statements)

References 35 publications

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“…2). This is consistent with studies of similar [Co II (TMC)X] n+ complexes [X = NCS À (Burgess et al, 1999), N 3 À (Evangelio et al, 2012;Reimer et al, 1989), and CH 3 CN (Jo et al, 2008) The cation of [Co II Cl(TMC)]ClÁ2H 2 O, (1), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.…”

Section: Resultssupporting

confidence: 89%

“…X-ray diffraction studies of the purple crystals showed that complex (1) crystallized in the monoclinic P2 1 /c space group. Selected geometric parameters are reported in (Burgess et al, 1999), N 3 À (Evangelio et al, 2012;Reimer et al, 1989), and CH 3 CN (Jo et al, 2008) (Alcock et al, 1978;Bucher et al, 2001;Nishigaki et al, 2010). The analogous iron complex contains an unusually short Fe II -Cl bond length of 2.2051 Å (Bedford et al, 2016).…”

Section: Resultsmentioning

confidence: 99%

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Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

et al. 2017

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The tetraazamacrocyclic ligand 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMC) has been used to bind a variety of first-row transition metals but to date the crystal structure of the cobalt(II) complex has been missing from this series. The missing cobalt complex chlorido(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane-κ4 N)cobalt(II) chloride dihydrate, [CoCl(C14H32N4)]Cl·2H2O or [CoIICl(TMC)]Cl·2H2O, crystallizes as a purple crystal. This species adopts a distorted square-pyramidal geometry in which the TMC ligand assumes the trans-I configuration and the chloride ion binds in the syn-methyl pocket of the ligand. The CoII ion adopts an S = 3 \over 2 spin state, as measured by the Evans NMR method, and UV–visible spectroscopic studies indicate that the title hydrated salt is stable in solution. Density functional theory (DFT) studies reveal that the geometric parameters of [CoIICl(TMC)]Cl·2H2O are sensitive to the cobalt spin state and correctly predict a change in spin state upon a minor perturbation to the ligand environment.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

et al. 2017

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“…[Co(12-TMC)O 2 ](ClO 4 ) ( 1 ),17 [Co(14-TMC)O 2 ](ClO 4 ) ( 2 ),18 [Co(12-TMC)(CH 3 CN)](ClO 4 ) 2 ( 1 pre , precursor of 1 )17 and [Co(14-TMC)(CH 3 CN)](ClO 4 ) 2 ( 2 pre , precursor of 2 )18 were synthesized as previously described. Caution: Perchlorate salts are potentially explosive and should be handled with care!…”

Section: Methodsmentioning

confidence: 99%

XAS and DFT Investigation of Mononuclear Cobalt(III) Peroxo Complexes: Electronic Control of the Geometric Structure in CoO₂ versus NiO₂ Systems

et al. 2010

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The geometric and electronic structures of two mononuclear [(L)CoO2]+ complexes, [(12-TMC)CoO2](ClO4) (1) and [(14-TMC)CoO2](ClO4) (2), have been evaluated using Co K-edge x-ray absorption spectroscopy (XAS) and extended x-ray absorption fine structure (EXAFS) and correlated with density functional theory (DFT) calculations to evaluate the differences in geometric and electronic structure due to changes in the TMC chelate ring size. Co K-edge XAS shows that both 1 and 2 are Co(III) species. Co K-edge EXAFS data show that both 1 and 2 are side-on O2 bound Co(III)-peroxide complexes. A combination of EXAFS and DFT calculations reveal that while the constrained 12-TMC ring in 1 allows for side-on O2 binding to the Co center with ease, the 14-TMC chelate in 2 has to undergo significant distortion of the ring to overcome steric hindrance posed by the four cis-methyl groups of the chelate to allow side-on O2 binding to the Co center. The Ni analogue of 2, [(14-TMC)NiO2]+, has been shown to form an end-on bound Ni(II)-superoxide species. The electronic and geometric factors that determine the different electronic structures of 2 and [(14-TMC)NiO2]+ are evaluated using DFT calculations. The results show that while the sterics of the cis-14-TMC chelate contribute to the geometry of O2 binding and results in an end-on bound Ni(II)-O2- complex in [(14-TMC)NiO2]+, the higher thermodynamic driving force for the oxidation of the Co(II) overcomes this steric constraint, resulting in the stabilization of a side-on bound Co(III)-O22- electronic structure in 2.

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“…The η 2peroxocobalt(III) complexes are sluggish oxidants with limited ability to perform hydroxylation, HAT, or OAT reactions; however, they are competent to perform oxidative nucleophilic reactions with aldehydes. 67,68,69 Nam et al have shown that treatment of [Co(η 2 -O2)] + complexes with acids provides a spectroscopically observable cobalt(III)-hydroperoxide species capable of both electrophilic and nucleophilic oxidation reactions. 68,70 When the 15-TMC ligand is employed, decay of the cobalt(III)-hydroperoxide species is accompanied by hydroxylation of the methyl group of the TMC ligand.…”

Section: Cobaltmentioning

confidence: 99%

Oxygen activation by mononuclear Mn, Co, and Ni centers in biology and synthetic complexes

Fiedler

Fischer

2016

J Biol Inorg Chem

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The active sites of metalloenzymes that catalyze O-dependent reactions generally contain iron or copper ions. However, several enzymes are capable of activating O at manganese or nickel centers instead, and a handful of dioxygenases exhibit activity when substituted with cobalt. This minireview summarizes the catalytic properties of oxygenases and oxidases with mononuclear Mn, Co, or Ni active sites, including oxalate-degrading oxidases, catechol dioxygenases, and quercetin dioxygenase. In addition, recent developments in the O reactivity of synthetic Mn, Co, or Ni complexes are described, with an emphasis on the nature of reactive intermediates featuring superoxo-, peroxo-, or oxo-ligands. Collectively, the biochemical and synthetic studies discussed herein reveal the possibilities and limitations of O activation at these three "overlooked" metals.

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Reactivity of a cobalt(III)-peroxo complex in oxidative nucleophilic reactions

Cited by 61 publications

References 35 publications

Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

XAS and DFT Investigation of Mononuclear Cobalt(III) Peroxo Complexes: Electronic Control of the Geometric Structure in CoO₂ versus NiO₂ Systems

Oxygen activation by mononuclear Mn, Co, and Ni centers in biology and synthetic complexes

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Reactivity of a cobalt(III)-peroxo complex in oxidative nucleophilic reactions

Cited by 61 publications

References 35 publications

Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

XAS and DFT Investigation of Mononuclear Cobalt(III) Peroxo Complexes: Electronic Control of the Geometric Structure in CoO2 versus NiO2 Systems

Oxygen activation by mononuclear Mn, Co, and Ni centers in biology and synthetic complexes

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XAS and DFT Investigation of Mononuclear Cobalt(III) Peroxo Complexes: Electronic Control of the Geometric Structure in CoO₂ versus NiO₂ Systems