Synthesis and Molecular Structure of Bis(ethylenediamine)acetatonickel(II)hexafluoridophosphate Complex [Ni(en)2(CH3CO2)]PF6. An Unexpected Acetylacetonato Cleavage Reaction

Martin, Maria da Graça M.B.; Hörner, Manfredo; Behm, Mariana Boneberger; Nunes, Fábio Souza

doi:10.1002/zaac.201100094

Cited by 7 publications

(5 citation statements)

References 21 publications

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“…For 8, there are two molecules of CH 2 Cl 2 per formula unit. CCDC-827741 (5·C 4 H 10 O), CCDC-827742 (6), and CCDC-827743 (8·2 CH 2 Cl 2 ) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.…”

Section: Methodsmentioning

confidence: 99%

“…The products of each aerobic photochemical reaction were determined after irradiating a 0.002 m solution of each complex (4)(5)(6) in acetonitrile at 350 nm for 20 h, under an aerobic atmosphere. The Ni II -containing products were identified by using 1 H NMR spectroscopy ( Figures 5-7) and ESI-MS.…”

Section: Complex Synthesis and Characterizationmentioning

confidence: 99%

“…[17] The reaction of 6 ( Figure 7) differs from that of 4 and 5 in that 1 H NMR resonances from the starting material are clearly evident in the 1 H NMR and ESI-MS spectra after 20 h of irradiation. Note that as a control, 0.002 m solutions of 4-6 in CD 3 CN were stored in the dark under ambient aerobic conditions for sev- 108.5037 (6) 77.5113 (7) 97.2779 (7) b [8] 104.6479 (9) 76.7675(10) 92.9850 (7) g [8] 102.9892 (9) 68.7334 (9) 112.8856(7)…”

Section: Complex Synthesis and Characterizationmentioning

confidence: 99%

“…The approach toward investigathave reported the formation of [Ni(en) 2 The oxidative cleavage of acac À to give acetate is suggested to involve superoxide generated in the reaction mixture, however no further details were provided. [6] As can be seen in the chemistry of Ni-ARD, Dke1, and related model systems, specific combinations of b-diketonate ligand and metal ion impart oxidative carbon-carbon bondcleavage reactivity. In Ni-ARD, a typically redox-inactive metal center stabilizes the dianionic form of a b-diketonatetype substrate having inherent reductive reactivity toward O 2 .…”

Section: Introductionmentioning

confidence: 99%

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Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate Ni^II Complexes

Allpress

Arif

Houghton

et al. 2011

Chemistry A European J

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Three mononuclear Ni(II) complexes containing a 2-chloro-1,3-diketonate ligand and supported by the 6-Ph(2)TPA chelate, as well as analogues that lack the 2-chloro substituent on the β-diketonate ligand, have been prepared and characterized. Upon irradiation at 350 nm under aerobic conditions, complexes containing the 2-chloro-substituted ligands undergo reactions to generate products resulting from oxidative cleavage, α-cleavage, and radical-derived reactions involving the 2-chloro-1,3-diketonate ligand. Mechanistic studies suggest that the oxidative cleavage reactivity, which leads to the production of carboxylic acids, is a result of the formation of superoxide, which occurs through reaction of reduced nickel complexes with O(2). The presence of the 2-chloro substituent was found to be a prerequisite for oxidative carbon-carbon bond-cleavage reactivity, as complexes lacking this functional group did not undergo these reactions following prolonged irradiation. The approach toward investigating the oxidative reactivity of metal β-diketonate species outlined herein has yielded results of relevance to the proposed mechanistic pathways of metalloenzyme-catalyzed β-diketonate oxidative cleavage reactions.

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Section: Methodsmentioning

confidence: 99%

Section: Complex Synthesis and Characterizationmentioning

confidence: 99%

Section: Complex Synthesis and Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate Ni^II Complexes

Allpress

Arif

Houghton

et al. 2011

Chemistry A European J

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“…As it was mentioned earlier the oxidative reactivity of unsubstituted diketonate substrates by Nickel(II) complexes has been reported. 21,22,35 The conclusions from this work showed that unsubstituted diketonates e.g. acetylacetonate, are generally unreactive towards oxidative cleavage.…”

Section: Proposed Mechanism For Reactivitymentioning

confidence: 80%

A family of structural and functional models for the active site of a unique dioxygenase: Acireductone dioxygenase (ARD)

Blade

Parveen

Jaimes

et al. 2020

Journal of Inorganic Biochemistry

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Oxidative aliphatic carbon–carbon bond cleavage reactions

Allpress

Berreau

2013

Coordination Chemistry Reviews

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The work presented in this dissertation has focused on synthesizing complexes of relevance to dioxygenase enzymes that oxidatively cleave aliphatic carbon-carbon bonds. The goal of this research was to elucidate mechanistic aspects of the activation of aliphatic carbon-carbon bonds towards cleavage by reaction with oxygen, and also investigate the regioselectivity of these reactions. The oxidative cleavage of a variety of enolizable substrates has been explored by utilizing several transition metal complexes supported by an aryl-appended tris(pyridylmethyl)amine ligand. In order to probe the widely-accepted "chelate hypothesis" for how changes in regiospecificity are achieved as a function of metal ion, we synthesized the compound [(6-Ph 2 TPA)Fe(PhC(O)COHC(O)Ph)]OTf. Based on UV-vis and IR spectroscopy, the acireductone enolate was found to bind via a six-membered chelate ring. By comparison with the reactivity of [(6-Ph 2 TPA)Ni(PhC(O)COHC(O)Ph)]ClO 4 , we determined that the chelate hypothesis was an insufficient explanation of the observed regioselectivity. iv Rather, ferrous ion-mediated hydration of a vicinal triketone intermediate was the key factor in determining the regioselectivity of the CC cleavage reaction. We have developed a high-yielding synthetic route to protected precursors of C(1)H acireductones. Preparation of the complexes [(6-Ph 2 TPA)M(PhC(O)COCHOC(O)CH 3)]ClO 4 (M = Fe, Ni) followed by judicious choice of deprotecting conditions allowed us to investigate the oxygen reactivity of a mononuclear complex with a dianionic acireductone substrate for the first time. This provides a promising strategy to continue investigations of complexes of relevance to the enzymesubstrate adduct of the acireductone dioxygenases. Divalent late first-row transition metal complexes have been used to investigate some new strategies for the activation of dioxygen and subsequent cleavage of CC bonds. We have utilized photoreduction of a Ni(II) center to generate a highly O 2-reactive Ni(I) fragment that leads to cleavage of a chloro-diketonate substrate. Additionally, we have found a Cu(II)-mediated thermal cleavage of chloro-diketonate substrates at room temperature. This reaction is interestingly accelerated by the addition of a catalytic amount of chloride ion.

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Synthesis and Molecular Structure of Bis(ethylenediamine)acetatonickel(II)hexafluoridophosphate Complex [Ni(en)₂(CH₃CO₂)]PF₆. An Unexpected Acetylacetonato Cleavage Reaction

Cited by 7 publications

References 21 publications

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate Ni^II Complexes

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate Ni^II Complexes

A family of structural and functional models for the active site of a unique dioxygenase: Acireductone dioxygenase (ARD)

Oxidative aliphatic carbon–carbon bond cleavage reactions

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Synthesis and Molecular Structure of Bis(ethylenediamine)acetatonickel(II)hexafluoridophosphate Complex [Ni(en)2(CH3CO2)]PF6. An Unexpected Acetylacetonato Cleavage Reaction

Cited by 7 publications

References 21 publications

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate NiII Complexes

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate NiII Complexes

A family of structural and functional models for the active site of a unique dioxygenase: Acireductone dioxygenase (ARD)

Oxidative aliphatic carbon–carbon bond cleavage reactions

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Product

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About

Synthesis and Molecular Structure of Bis(ethylenediamine)acetatonickel(II)hexafluoridophosphate Complex [Ni(en)₂(CH₃CO₂)]PF₆. An Unexpected Acetylacetonato Cleavage Reaction

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate Ni^II Complexes

Photochemically Initiated Oxidative Carbon–Carbon Bond‐Cleavage Reactivity in Chlorodiketonate Ni^II Complexes