Enthalpy of formation of trifluoroacetonitrile

Walker, Lynn C.; Sinke, G. C.; Perettie, D. J.; Janz, George J.

doi:10.1021/ja00718a006

Cited by 17 publications

(16 citation statements)

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“…In alcoholic media as the proton source the oxidation of [Co(II)(Por)(L)] to [Co(III)(Por)(L 2 )] + is reported 48. In the reversible case reported by Walker, the carefully purified toluene solution excluded water and the EPR signal can be restored by pumping off the dioxygen 3. In our system, the combination of the protecting “picket fence” and the bulky 2-methylimidazole would appear to preclude the formation of the peroxo-bridged binuclear complex but could allow hydrogen bonding to the O 2 by excess 2-methylimidazole.…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, five-coordinate cobalt(II) porphyrinates show reversible binding of dioxygen 3. Cobalt myoglobin and cobalt hemoglobin, “coboglobin”, in which the heme prosthetic group (iron protoporphyrin IX) is replaced by cobalt protoporphyrin IX display reversible oxygen binding similar to those of their native iron counterparts 4.…”

Section: Introductionmentioning

confidence: 99%

“…These species have been the subject of interest for many years in regard to the nature of the bond between cobalt and oxygen in the monomeric oxygen adducts 2. The reactions required for understanding the O 2 interactions with cobalt porphyrinates, [Co(Por)(L)],5 are shown below 3…”

Section: Introductionmentioning

confidence: 99%

“…It is perhaps not surprising that no bis(imidazole)-ligated Co(II) porphyrinate has ever been isolated. Second, a number of Co(II) porphyrins can form 1:1 mononuclear oxygen adducts that are generally reversible (reaction 3) 3, 8. Third, both reversible and irreversible reactions have been reported for forming the 1:2 peroxo-bridged binuclear complexes [(L)(Por)Co(O 2 )Co(Por)(L)] (reaction 4).…”

Section: Introductionmentioning

confidence: 99%

“…Third, both reversible and irreversible reactions have been reported for forming the 1:2 peroxo-bridged binuclear complexes [(L)(Por)Co(O 2 )Co(Por)(L)] (reaction 4). For example, in a carefully purified toluene solution the decreased EPR signal due to formation of [(L)(Por)Co(O 2 )Co(Por)(L)] could be restored by heating or pumping off dioxygen to decompose the diamagnetic binuclear products 3. However, under some conditions an irreversible reaction takes place.…”

Section: Introductionmentioning

confidence: 99%

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Oxygenation of Cobalt Porphyrinates: Coordination or Oxidation?

Noll

Oliver

et al. 2010

Inorg. Chem.

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The X-ray characterization of the five-coordinate picket-fence porphyrin complex, [Co(TpivPP)(2-MeHim)], is reported. The complex has the displacement of cobalt from the porphyrin plane = 0.15 Å, and Co-N Im = 2.145 (3) and (Co-N p ) av = 1.979(3) Å. This five-coordinate complex, in the presence of dioxygen and excess 2-methylimidazole, undergoes an unanticipated, photoinitiated atropisomerization of the porphyrin ligand, oxidation of cobalt(II) and the formation of the neutral cobalt(III) complex [Co(α,α,β,β-TpivPP)(2-MeHim)(2-MeIm − ]. Two distinct examples of this complex have been structurally characterized, both have structural parameters consistent with cobalt (III). The two new Co(III) porphyrin complexes have axial Co-N Im distances ranging from 1.952 to 1.972 Å, but which allow for the distinction between imidazole and imidazolate. An interesting intermolecular hydrogen bonding network is observed that leads to infinite helical chains. UV-vis spectroscopic study suggests that [Co(TpivPP)(2-MeHIm)(O 2 )] is an intermediate state for the oxidation reaction and the atropisomerization process is photocatalyzed. A reaction route is proposed based on the spectroscopic studies.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%