Binding of dioxygen to metal complexes. The oxygen adduct of Co(acacen)

Dedieu, Alain; Rohmer, Marie‐Madeleine; Veillard, A.

doi:10.1021/ja00435a009

Cited by 70 publications

(32 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is clearly supported by the EPR spectra 41, 42 that indicates that the unpaired electron resides in a π * antibonding molecular orbital predominantly localized on dioxygen. 43 The possible formulation of the oxyiron complexes as

Fe (III) - (O_{2}^{-})

has been more contentious starting from the Pauling/Weiss debate 44, 45 and continuing to the present time. 43b,46, 47 …”

Section: Discussionmentioning

confidence: 99%

Structural Insights into Ligand Dynamics: Correlated Oxygen and Picket Motion in Oxycobalt Picket Fence Porphyrins

Noll

Oliver

et al. 2012

J. Am. Chem. Soc.

View full text Add to dashboard Cite

Two different oxygen-ligated cobalt porphyrins have been synthesized and the solid-state structures have been determined at several temperatures. The solid-state structures provide insight into the dynamics of Co–O2 rotation and correlation with protecting group disorder. [Co(TpivPP)(1-EtIm)(O2)] (TpivPP = picket fence porphyrin) is prepared by oxygenation of [Co(TpivPP)(1-EtIm)2] in benzene solution. The structure at room temperature has the oxygen ligand within the ligand binding pocket and disordered over four sites and the trans imidazole is disordered over two sites. The structure at 100 K, after the crystal has been carefully annealed to yield a reversible phase change, is almost completely ordered. The phase change is reversed upon warming the crystal to 200 K, whereupon the oxygen ligand is again disordered but with quite unequal populations. Further warming to 300 K leads to greater disorder of the oxygen ligands with nearly equal O2 occupancies at all four positions. The disorder of the t-butyl groups of the protecting pickets is correlated with rotation of the O2 around the Co–O(O2) bond. [Co(TpivPP)(2-MeHIm)(O2)] is synthesized by a solid-state oxygenation reaction from the five-coordinate precursor [Co(TpivPP)(2-MeHIm)]. Exposure to 1 atm of O2 leads to incomplete oxygenation, however, exposure at 5 atm yields complete oxygenation. Complete oxygenation leads to picket disorder whereas partial (40%) oxygenation does not. Crystallinity is retained on complete degassing of oxygen in the solid, and complete ordering of the pickets is restored. The results should provide basic information needed to better model M–O2 dynamics in protein environments.

show abstract

Fe (III) - (O_{2}^{-})

has been more contentious starting from the Pauling/Weiss debate 44, 45 and continuing to the present time. 43b,46, 47 …”

Section: Discussionmentioning

confidence: 99%

Structural Insights into Ligand Dynamics: Correlated Oxygen and Picket Motion in Oxycobalt Picket Fence Porphyrins

Noll

Oliver

et al. 2012

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…[26][27][28][29] Veillard studied the binding of dioxygen to Co(Acacen) and compared the stability of different binding structural models, such as linear M-O-O units, end-on angular bonds, and side-ways perpendicular structures. 30 It is indicated that the end-on model was the most stable one. Additionally, Henson et al compared the binding processes of molecular oxygen with Co(Acacen)(pyridine) and Co(Salen)(pyridine), respectively.…”

Section: Introductionmentioning

confidence: 99%

Toward understanding macrocycle specificity of iron on the dioxygen-binding ability: a theoretical study

Sun

Chen

Liu

et al. 2011

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

In an effort to examine the interaction between dioxygen and iron-macrocyclic complexes, and to understand how this interaction was affected by those different macrocyclic ligands, dioxygen binding with iron-porphyrin, iron-phthalocyanine, iron-dibenzotetraaza[14]annulene, and iron-salen complexes is investigated by means of quantum chemical calculations utilizing Density Functional Theory (DFT). Based on the analysis of factors influencing the corresponding dioxygen binding process, it showed that different macrocyclic ligands possess different O-O bond distances, and different electronic configurations for the bound O(2) and non-aromatic macrocyclic ligands favor dioxygen activation. Furthermore, the smaller the energy gap between the HOMO of iron-macrocyclic complexes and the LUMO of dioxygen, the more active the bound O(2) becomes, with a longer O-O bond distance and a shorter Fe-O bond length.

show abstract

“…Nevertheless, the macrocyclic complexes have been reported as peroxo species. 24 The Schiff base complexes of cobalt were the subject of single point ab initio Hartree-Fock studies (1978) 13 as well as recent DFT calculations (1999) 12 carried out with fully optimized structures. In agreement with the experiment, both studies show that the [Co]-O 2 complex has a doublet spin state and formally can be described as a superoxocobalt(III) compound.…”

Section: Introductionmentioning

confidence: 99%

How molecular oxygen binds to bis[trifluoroacetylacetonato(−1)]cobalt(ii) –ab initio and density functional theory studies

2011

View full text Add to dashboard Cite

Cobalt(II) diketonate complexes, such as bis[trifluoroacetylacetonato(-1)]cobalt(II) [Co(tfa)(2)], catalyze the aerobic oxidation of alkenols into functionalized tetrahydrofurans. To gain insight into activation of triplet dioxygen by Co(tfa)(2) in a protic solvent, as used in oxidation catalysis, the electronic structure of aquabis[trifluoroacetylacetonato(-1)]cobalt(II)--Co(tfa)(2)(H(2)O)--and the derived dioxygen adduct were characterized using ab initio (CASSCF, NEVPT2) and density functional theory (BP86, TPSSh, B3LYP) methods. The ground state of Co(tfa)(2)(H(2)O) is a high-spin, quartet state. As dioxygen approaches the cobalt atom, the quartet state couples with a triplet dioxygen molecule and forms a sextet, a quartet, and a doublet spin state with the high-spin state being the lowest in energy. At the equilibrium Co-O(2) distance of 1.9 Å, Co(tfa)(2)(H(2)O)(O(2)) has a doublet superoxo Co(III) ground state with the unpaired electron residing on the oxygen moiety, in a nearly unchanged O(2)π* orbital.

show abstract

Binding of dioxygen to metal complexes. The oxygen adduct of Co(acacen)

Cited by 70 publications

References 18 publications

Structural Insights into Ligand Dynamics: Correlated Oxygen and Picket Motion in Oxycobalt Picket Fence Porphyrins

Structural Insights into Ligand Dynamics: Correlated Oxygen and Picket Motion in Oxycobalt Picket Fence Porphyrins

Toward understanding macrocycle specificity of iron on the dioxygen-binding ability: a theoretical study

How molecular oxygen binds to bis[trifluoroacetylacetonato(−1)]cobalt(ii) –ab initio and density functional theory studies

Contact Info

Product

Resources

About