Synthesis and spectroscopic properties of Co(salen) derivatives containing pendant thioether groups and their dioxygen adducts

Nakamoto, Kazuo; Oshio, Hiroki; Ökawa, Hisashi; Kanda, Wakako; Horiuchi, Kiyoko; Kida, Sigeo

doi:10.1016/s0020-1693(00)81286-4

Cited by 11 publications

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References 19 publications

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“…Oxygenation of 1 − 6 in DMF was studied by means of electronic spectral and NMR techniques. The introduction of dioxygen into a DMF solution of 1 (CoMn) at 0 °C caused an immediate color change from red to dark red and showed a fairly intense band near 600 nm (ε 2310 M -1 cm -1 ) characteristic of the Co(salen)/O 2 adduct , (Figure , trace b). When the solution was purged with argon, the spectrum of 1 was recovered (trace a).…”

Section: Resultsmentioning

confidence: 99%

(μ-Phenoxo)₂Co^IIM^II (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring M^II Effects upon Oxygenation at the Co(salen) Center

1999

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The phenol-based macrocyclic ligands (L2,3)2- and (L2,4)2-, derived from the [2:1:1] condensation of 2,6-diformyl-4-methylphenol, ethylenediamine, and 1,3-trimethylenediamine or 1,4-tetramethylenediamine, have a salen-like metal-binding site (salen = N,N‘-ethylenedisalicylideneaminate) and a saltn- or salbn-like metal-binding site (saltn = N,N‘-trimethylenedisalicylideneaminate, salbn = N,N‘-tetramethylenedisalicylideneaminate) sharing the phenolic moieties. They form the (μ-phenoxo)2CoIIMII complexes [CoMn(L2,3)(AcO)]ClO4·DMF (1), [CoMn(L2,4)(AcO)]ClO4 (2), [CoCo(L2,3)(AcO)]ClO4 (3), [CoCo(L2,4)(AcO)]ClO4 (4), [CoZn(L2,3)(AcO)]ClO4 (5), and [CoZn(L2,4)(AcO)]ClO4 (6). Complex 1 crystallizes in the monoclinic space group P21/c, with a = 10.027(3) Å, b = 11.713(3) Å, c = 26.821(9) Å, β = 93.85(2)°, V = 3142(1) Å3, and Z = 4. The Co and Mn ions are bridged by the two phenolic oxygens of the macrocycle and an acetate group in the syn-syn mode. The CoII in the salen site is of low-spin and assumes a square-pyramidal geometry with an acetate oxygen at the axial site. The MnII has a cis six-coordinate geometry with respect to the acetate oxygen and the DMF oxygen. The Mn is displaced 0.955 Å from the basal N2O2 least-squares plane. [CoMn(L2,4)(AcO)]ClO4·DMF (2 ‘) crystallizes in the monoclinic space group P21/c, with a = 10.166(5) Å, b = 11.934(4) Å, c = 27.380(8) Å, β = 93.97(3)°, V = 3313(1) Å3, and Z = 4. It has a dinuclear core similar to that of 1, with square-pyramidal CoII in the salen site and cis six-coordinate MnII in the salbn site. Complex 3 crystallizes in the triclinic space group P1̄, a = 12.118(3) Å, b = 12.156(2) Å, c = 9.977(1) Å, α = 112.49(1)°, β = 99.22(2)°, γ = 77.63(2)°, V = 1321.1(5) Å3, and Z = 2. Both CoII ions in the salen and saltn sites assume a square-pyramidal geometry with a bridging acetate group in the syn-syn mode. The displacement of the Co in the saltn site, from the basal N2O2 least-squares plane toward the apical acetate oxygen, is 0.53 Å. Complex 5 is found to be isostructural with 3. The complexes 1, 2, 4, 5, and 6 are reversibly oxygenated in DMF at 0 °C to afford a μ-peroxo dimer complex [{CoIIIMII(L)(AcO)}2(O2 2-)]2+. Complex 3 also forms such a μ-peroxo dimer complex but is irreversibly oxidized through an intramolecular-type μ-peroxo complex [CoIIICoIII(L2,3)(AcO)(O2 2-)]+.

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Section: Resultsmentioning

confidence: 99%

(μ-Phenoxo)₂Co^IIM^II (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring M^II Effects upon Oxygenation at the Co(salen) Center

1999

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“…Conversions between peroxides and superoxides have been achieved, too, but typically these required the addition of external redox equivalents in the form of a reducing metal ion or a different reductant, or via the O 2 pressure (which induces redox chemistry involving the O 2 ). − Intramolecular redox conversions, leading selectively to one species or another triggered by an external stimulus (like solvent or ligand as in the above-mentioned [(TACN)Cu] 2 O 2 case) have not been reported yet. Examples, where peroxide and superoxide forms were observed for defined redox couples include spectroscopic evidence for the transformation of an initially formed heme−μ-peroxo–Cu II intermediate into the heme–superoxo-Cu I species in the course of the reaction between a heme-Cu I precursor and O 2 .…”

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Switching from a Chromium(IV) Peroxide to a Chromium(III) Superoxide upon Coordination of a Donor in the trans Position

et al. 2019

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O2 activation at a chromium(II) siloxide complex in propionitrile leads to a chromium(III) complex with an end-on bound superoxide ligand, while the reaction in tetrahydrofuran leads to a side-on peroxo chromium(IV) compound. The superoxide reacts faster with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl hydroxylamine while the peroxide, unlike the superoxide, proved capable of deformylating aldehydes. The system was found to represent a unique case, where even a switching between the two structures can be achieved via the solvent; its ability to coordinate at the position trans to the O2 ligand is decisive, as supported by density functional theory studies. Altogether, the results show that subtle changes can determine for an initially formed metal-dioxygen adduct, whether it exists as a superoxide or a peroxide, which thus merits consideration in discussions on mechanisms and possible reaction routes.

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ChemInform Abstract: Synthesis and Spectroscopic Properties of Co(salen) Derivatives Containing Pendant Thioether Groups and Their Dioxygen Adducts.

Nakamoto¹,

Oshio²,

Ökawa³

et al. 1986

Chemischer Informationsdienst

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Synthesis and spectroscopic properties of Co(salen) derivatives containing pendant thioether groups and their dioxygen adducts

Cited by 11 publications

References 19 publications

(μ-Phenoxo)₂Co^IIM^II (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring M^II Effects upon Oxygenation at the Co(salen) Center

(μ-Phenoxo)₂Co^IIM^II (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring M^II Effects upon Oxygenation at the Co(salen) Center

Switching from a Chromium(IV) Peroxide to a Chromium(III) Superoxide upon Coordination of a Donor in the trans Position

ChemInform Abstract: Synthesis and Spectroscopic Properties of Co(salen) Derivatives Containing Pendant Thioether Groups and Their Dioxygen Adducts.

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Synthesis and spectroscopic properties of Co(salen) derivatives containing pendant thioether groups and their dioxygen adducts

Cited by 11 publications

References 19 publications

(μ-Phenoxo)2CoIIMII (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring MII Effects upon Oxygenation at the Co(salen) Center

(μ-Phenoxo)2CoIIMII (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring MII Effects upon Oxygenation at the Co(salen) Center

Switching from a Chromium(IV) Peroxide to a Chromium(III) Superoxide upon Coordination of a Donor in the trans Position

ChemInform Abstract: Synthesis and Spectroscopic Properties of Co(salen) Derivatives Containing Pendant Thioether Groups and Their Dioxygen Adducts.

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(μ-Phenoxo)₂Co^IIM^II (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring M^II Effects upon Oxygenation at the Co(salen) Center

(μ-Phenoxo)₂Co^IIM^II (M = Mn, Co, Zn) Complexes with a Co(salen) Entity in a Macrocyclic Framework: Core Structures and Neighboring M^II Effects upon Oxygenation at the Co(salen) Center