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The second case of linear end‐on and evidence for an unprecedented bridging end‐on coordination mode of CO2 have been discovered for vanadium aryloxide complexes of the tetradentate ligand system (ONNO)2− (ONNO=2,4‐Me2‐2‐(OH) C6H2CH2]2N(CH2)2NMe2). The reaction of divalent (ONNO)VII (TMEDA) with CO2 and under the appropriate reaction conditions affords the trivalent (ONNO)VIII(OH)(η1‐CO2) resulting from an intermediate CO2 deoxygenation pathway followed by H‐atom abstraction from the aromatic solvent, and CO2 fixation. In contrast, the reduction of trivalent (ONNO)VIIICl(THF) with K, followed by exposure to CO2 in ethereal solvent, afforded the dinuclear [(ONNO)VII]2 (μ,η1‐CO2). [ABSTRACT FROM AUTHOR]

The second case of linear end‐on and evidence for an unprecedented bridging end‐on coordination mode of CO2 have been discovered for vanadium aryloxide complexes of the tetradentate ligand system (ONNO)2− (ONNO=2,4‐Me2‐2‐(OH) C6H2CH2]2N(CH2)2NMe2). The reaction of divalent (ONNO)VII (TMEDA) with CO2 and under the appropriate reaction conditions affords the trivalent (ONNO)VIII(OH)(η1‐CO2) resulting from an intermediate CO2 deoxygenation pathway followed by H‐atom abstraction from the aromatic solvent, and CO2 fixation. In contrast, the reduction of trivalent (ONNO)VIIICl(THF) with K, followed by exposure to CO2 in ethereal solvent, afforded the dinuclear [(ONNO)VII]2 (μ,η1‐CO2). [ABSTRACT FROM AUTHOR]

Abstract: Treatment of divalent (ONNO)V(TMEDA) (1; ONNO=[2,4‐Me2‐2‐(OH)C6H2CH2]2N(CH2)2NMe2) with CO2 afforded [(ONNO)V]2(μ‐OH)(μ‐formate) (2). Whereas the bridging hydroxo and formate groups both originated from CO2, the H atoms present on the two residues were obtained through H‐atom radical abstraction from the solvent. DFT calculations revealed an initially linear CO2 bonding mode, followed by deoxygenation, and highlighted a synergistic effect between the so‐formed oxo group and an additional bridging CO2 residue in promoting radical behavior. [ABSTRACT FROM AUTHOR]

The reactivity of carbon dioxide with vanadium(III) aryloxo complexes has been investigated. The formation of either carbon monoxide or incorporation into the ligand system with the ultimate formation of organic ester was observed depending on the overall electron donor ability of the ligand field. DFT calculations were carried out to investigate the proposed mechanism for carbon dioxide coordination and reduction. [ABSTRACT FROM AUTHOR]

Innentitelbild: Linear End-On Coordination Modes of CO2 (Angew. Chem. 42/2019) Wie stark wird die Reaktivität. [Extracted from the article]

The second case of linear end‐on and evidence for an unprecedented bridging end‐on coordination mode of CO2 have been discovered for vanadium aryloxide complexes of the tetradentate ligand system (ONNO)2− (ONNO=2,4‐Me2‐2‐(OH) C6H2CH2]2N(CH2)2NMe2). The reaction of divalent (ONNO)VII (TMEDA) with CO2 and under the appropriate reaction conditions affords the trivalent (ONNO)VIII(OH)(η1‐CO2) resulting from an intermediate CO2 deoxygenation pathway followed by H‐atom abstraction from the aromatic solvent, and CO2 fixation. In contrast, the reduction of trivalent (ONNO)VIIICl(THF) with K, followed by exposure to CO2 in ethereal solvent, afforded the dinuclear [(ONNO)VII]2 (μ,η1‐CO2). [ABSTRACT FROM AUTHOR]

The second case of linear end‐on and evidence for an unprecedented bridging end‐on coordination mode of CO2 have been discovered for vanadium aryloxide complexes of the tetradentate ligand system (ONNO)2− (ONNO=2,4‐Me2‐2‐(OH) C6H2CH2]2N(CH2)2NMe2). The reaction of divalent (ONNO)VII (TMEDA) with CO2 and under the appropriate reaction conditions affords the trivalent (ONNO)VIII(OH)(η1‐CO2) resulting from an intermediate CO2 deoxygenation pathway followed by H‐atom abstraction from the aromatic solvent, and CO2 fixation. In contrast, the reduction of trivalent (ONNO)VIIICl(THF) with K, followed by exposure to CO2 in ethereal solvent, afforded the dinuclear [(ONNO)VII]2 (μ,η1‐CO2). [ABSTRACT FROM AUTHOR]