Crystal and molecular structure of a new type of tetranuclear mixed valence copper complex: Cu4Ac6(Ph3P)4(Ac = O2CMe)

Koman, Marián; Valigura, Dušan; Ďurčanská, E.; Ondrejovič, G.

doi:10.1039/c39840000381

Cited by 7 publications

(3 citation statements)

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“…As mentioned before, initially a pink solution developed of compound 1, yielding a pink species with λ max ) 540 nm (Figure 4). We suggest that this might indicate substitution of the coordinated nitrile ligands by PPh 3 within the hydroperoxide complex (Scheme 5); although PPh 3 favors copper(I) ligation, it does bind Cu-(II) ions [52][53][54] and the excess (10-fold) PPh 3 would drive the reaction. This species may then slowly (over days at -80 °C, Figure 4) undergo O-O bond cleavage to yield a dicopper(II) coordinated phenoxyl radical red species with λ max ) 440 nm (Scheme 5); we suggest this possibility since Michel and co-workers 55 recently described a dicopper(II) phenoxyl radical complex with dinucleating ligand very similar to PD′O -(with quartet ground state), in fact possessing a 440 nm absorption.…”

Section: Resultsmentioning

confidence: 99%

Reactivity Study of a Hydroperoxodicopper(II) Complex: Hydroxylation, Dehydrogenation, and Ligand Cross-Link Reactions

Sarjeant

Karlin

2006

Inorg. Chem.

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Employing a binucleating phenol-containing ligand PD'OH, a mu-phenoxo-mu-hydroperoxo dicopper(II) complex [Cu(II)2(PD'O-)(-OOH)(RCN)2](ClO4)2 (1, R = CH3, CH3CH2 or C6H5CH2; lambda(max) = 407 nm; nu(O-O) = 870 cm(-1); J. Am. Chem. Soc. 2005, 127, 15360) is generated by reacting a precursor dicopper(I) complex [Cu(I)2(PD'OH)(CH3CN)2](ClO4)2 (2) with O2 in nitrile solvents at -80 degrees C. Species 1 is unable to oxidize externally added substrates, for instance, PPh3, 2,4-tert-butylphenol, or 9,10-dihydroanthracene. However, upon thermal decay, it hydroxylates copper-bound organocyanides (e.g., benzylcyanide), leading to the corresponding aldehyde while releasing cyanide. This chemistry mimics that known for the copper enzyme dopamine-beta-monooxygenase. The thermal decay of 1 also leads to a product [Cu(II)3(L")2(Cl-)2](PF6)2 (6); its X-ray structure reveals that L" is a Schiff base-containing ligand which apparently derives from both oxidative N-dealkylation and then oxidative dehydrogenation of PD'OH; the chloride presumably derives from the CH2Cl2 solvent. With an excess of PPh3 added to 1, a binuclear Cu(I) complex [Cu(I)2(L')(PPh3)2](ClO4)2 (5) with a cross-linked PD'OH ligand L' has also been identified and crystallographically and chemically characterized. The newly formed C-O bond and an apparent k(H)/k(D) = 2.9 +/- 0.2 isotope effect in the benzylcyanide oxidation reaction suggest a common ligand-based radical forms during compound 1 thermal decay reactions. A di-mu-hydroxide-bridged tetranuclear copper(II) cluster compound [{Cu(II)2(PD'O-)(OH-)}2](ClO4)4 (8) has also been isolated following warming of 1. Its formation is consistent with the generation of [Cu(II)2(PD'O-)(OH-)]2+, with dimerization a reflection of the large Cu...Cu distance and thus the preference for not having a second bridging ligand atom (in addition to the phenolate O) for dicopper(II) ligation within the PD'O- ligand framework.

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Section: Resultsmentioning

confidence: 99%

Reactivity Study of a Hydroperoxodicopper(II) Complex: Hydroxylation, Dehydrogenation, and Ligand Cross-Link Reactions

Sarjeant

Karlin

2006

Inorg. Chem.

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“…Examples of mixed valence copper complexes are plentiful. However, most of the previously reported mixed valence copper complexes involve bidentate or multidentate ligands as the bridging ligand for the Cu(II) and Cu(I) centers. − Only a few examples of mixed valence copper complexes where the Cu(II) and Cu(I) centers are linked together via monodentate halide ligands have been reported. 2d,, According to the crystal structure, compound 2 would belong to the class I mixed valence copper complexes, where there are distinct geometries for Cu(II) and Cu(I) ions and the unpaired electron is localized on the Cu(II) center. If compound 2 indeed behaves like a class I compound, based on previous studies, one would expect that the copper(II) ion has similar electronic structures in 1 and 2 , since the coordination environment of the Cu(II) ion in both compounds is essentially identical.…”

Section: Resultsmentioning

confidence: 99%

“…Efforts were made to further distinguish these three classes of mixed valence copper complexes by their electronic properties, in addition to the copper geometry. While it has been well documented that class II and class III compounds usually display significant d−d interactions and characteristic d → d charge transfer bands between the Cu(I) and Cu(II) centers, 1e, causing the intense color of these compounds, there have been few reports supporting the presence of perturbation by a Cu(I) ion to the electronic structure of a Cu(II) ion in a class I environment. , Recently, we have discovered a new mixed valence copper complex Cu II (Me 5 dien)Cl 2 (Cu I Cl) ( 2 ) (Me 5 dien = N , N , N‘ , N‘ , N‘‘ -pentamethyldiethylenetriamine) with a distinct class I structure. This compound can be obtained readily via the reaction of Cu II (Me 5 dien)Cl 2 ( 1 ) with Cu I Cl in a 1:1 ratio.…”

Section: Introductionmentioning

confidence: 99%

Perturbation of the Electronic Structure of a Copper(II) ion by a Cu^ICl Moiety in a Class I Mixed Valence Copper Complex, Cu^II(Me₅dien)Cl₂(Cu^ICl)

Breeze

Wang

1996

Inorg. Chem.

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A new mixed valence copper complex Cu(II)(Me(5)dien)Cl(2)(Cu(I)Cl) (2) was obtained from the reaction of CuCl with Cu(II)(Me(5)dien)Cl(2) (1) in acetonitrile. The structures of 1 and 2 have been determined by single-crystal X-ray diffraction analyses. Compound 1 crystallizes in the monoclinic space group P2(1)/n with a = 8.374(5) Å, b = 17.155(3) Å, c = 23.806(5) Å, beta = 94.40(4) degrees, Z = 8, and V = 3398(1) Å(3) while compound 2 crystallizes in orthorhombic space group Pbcn with a = 14.71(1) Å, b = 16.06(2) Å, c = 13.38(1) Å, Z = 8, and V = 3159(5) Å. The Cu(II)(Me(5)dien)Cl(2) unit in both compounds has a similar distorted square-pyramidal geometry. The Cu(I)Cl moiety in 2 is attached to the Cu(II) unit via two bridging chlorine atoms and has a distorted trigonal planar geometry. UV-vis and EPR spectroscopic studies and molecular orbital calculations established the presence of significant perturbation of the Cu(I)Cl unit to the electronic structure of the Cu(II) ion in compound 2.

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Ternary Mononuclear and Ferromagnetically Coupled Dinuclear Copper(II) Complexes of 1,10‐Phenanthroline and N‐Salicylidene‐2‐methoxyaniline that Show Supramolecular Self‐Organization

2003

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(2) have been prepared and characterized structurally by Xray crystallography (HL: N-salicylidene-2-methoxyaniline; phen: 1,10-phenanthroline). The crystal structure of 1 displays a square-pyramidal [4+1] coordination geometry in which the basal plane has three nitrogen donor atoms and the phenolate oxygen atom of the Schiff base. The methoxy oxygen atom exhibits axial coordination in the CuN 3 O 2 chromophore. Complex 2 has a dinuclear copper(II) core in which the Cu(phen) 2 2+ and Cu(phen)(L) + units are linked by an acetate ion showing equatorial/axial modes of bonding. In the bis(phen) unit, the basal plane has three nitrogen atoms and the acetate oxygen atom with one phen nitrogen atom occupying the axial site. In the mono(phen) unit, the basal plane has three nitrogen atoms and one phenolate oxygen atom. The acetate oxygen atom occupies the axial site. The equatorial/axial bridging mode of the acetate ion makes the dicopper(II) unit weakly ferromagnetic (2J = +22 cm −1 ) and the complex in CH 2 Cl 2 glass at 77 K shows an axial EPR

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Crystal and molecular structure of a new type of tetranuclear mixed valence copper complex: Cu₄Ac₆(Ph₃P)₄(Ac = O₂CMe)

Cited by 7 publications

References 1 publication

Reactivity Study of a Hydroperoxodicopper(II) Complex: Hydroxylation, Dehydrogenation, and Ligand Cross-Link Reactions

Reactivity Study of a Hydroperoxodicopper(II) Complex: Hydroxylation, Dehydrogenation, and Ligand Cross-Link Reactions

Perturbation of the Electronic Structure of a Copper(II) ion by a Cu^ICl Moiety in a Class I Mixed Valence Copper Complex, Cu^II(Me₅dien)Cl₂(Cu^ICl)

Ternary Mononuclear and Ferromagnetically Coupled Dinuclear Copper(II) Complexes of 1,10‐Phenanthroline and N‐Salicylidene‐2‐methoxyaniline that Show Supramolecular Self‐Organization

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Crystal and molecular structure of a new type of tetranuclear mixed valence copper complex: Cu4Ac6(Ph3P)4(Ac = O2CMe)

Cited by 7 publications

References 1 publication

Reactivity Study of a Hydroperoxodicopper(II) Complex: Hydroxylation, Dehydrogenation, and Ligand Cross-Link Reactions

Reactivity Study of a Hydroperoxodicopper(II) Complex: Hydroxylation, Dehydrogenation, and Ligand Cross-Link Reactions

Perturbation of the Electronic Structure of a Copper(II) ion by a CuICl Moiety in a Class I Mixed Valence Copper Complex, CuII(Me5dien)Cl2(CuICl)

Ternary Mononuclear and Ferromagnetically Coupled Dinuclear Copper(II) Complexes of 1,10‐Phenanthroline and N‐Salicylidene‐2‐methoxyaniline that Show Supramolecular Self‐Organization

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Crystal and molecular structure of a new type of tetranuclear mixed valence copper complex: Cu₄Ac₆(Ph₃P)₄(Ac = O₂CMe)

Perturbation of the Electronic Structure of a Copper(II) ion by a Cu^ICl Moiety in a Class I Mixed Valence Copper Complex, Cu^II(Me₅dien)Cl₂(Cu^ICl)