Linear End‐On Coordination Modes of CO 2

The second case of linear end‐on and evidence for an unprecedented bridging end‐on coordination mode of CO 2 have been discovered for vanadium aryloxide complexes of the tetradentate ligand system (ONNO) 2− (ONNO=2,4‐Me 2 ‐2‐(OH) C 6 H 2 CH 2 ] 2 N(CH 2 ) 2 NMe 2 ). The reaction of divalent (ONNO)V II (TMEDA) with CO 2 and under the appropriate reaction conditions affords the trivalent (ONNO)V III (OH)(η 1 ‐CO 2 ) resulting from an intermediate CO 2 deoxygenation pathway followed by H‐atom abstraction from the aromatic solvent, and CO 2 fixation. In contrast, the reduction of trivalent (ONNO)V III Cl(THF) with K, followed by exposure to CO 2 in ethereal solvent, afforded the dinuclear [(ONNO)V II ] 2 (μ , η 1 ‐CO 2 ).