[Ni^III(OMe)]-mediated reductive activation of CO₂ affording a Ni(κ¹-OCO) complex

Abstract

We report a novel pathway for the reductive activation of CO2 by the [NiIII(OMe)(P(C6H3-3-SiMe3-2-S)3)]– complex, yielding the [NiIII(κ1-OCO˙–)(P(C6H3-3-SiMe3-2-S)3)]– complex.

Metal–Ligand Cooperation as Key in Formation of Dearomatized NiII–H Pincer Complexes and in Their Reactivity toward CO and CO2

“… Since then, several similar Ni­(η 2 -CO 2 ) complexes have been reported, , including a unique five-coordinated Ni­(η 2 -CO 2 ) complex . A unique coordination mode of μ-η 2 ,η 2 -CO 2 in a dinuclear Ni complex was reported by Sadighi and co-workers, and a rare case of Ni III (η 1 -(CO 2 ) • -κ O ) was reported by Chiou, Liaw, and co-workers . Recently a rare case of Ni II (η 1 -CO 2 -κ C ) was reported by Lee (Scheme ).…”

“…60 A unique coordination mode of μ-η 2 ,η 2 -CO 2 in a dinuclear Ni complex was reported by Sadighi and co-workers, 61 and a rare case of Ni III (η 1 -(CO 2 ) • -κ O ) was reported by Chiou, Liaw, and co-workers. 62 Recently a rare case of Ni II (η 1 -CO 2 -κ C ) was reported by Lee 63 (Scheme 2).…”

Generation of a Mn(IV)–Peroxo or Mn(III)–Oxo–Mn(III) Species upon Oxygenation of Mono- and Binuclear Thiolate-Ligated Mn(II) Complexes

“…Treatment of transition-metal–thiolate complexes with O 2 frequently causes ligand-centered oxidation, resulting in the formation of metal–sulfenate, −sulfinate, or −sulfonate species. − On the other hand, coordination of chelating ligands containing strongly donating thiolato sulfur(s) is found to help metal-based O 2 activation by lowering the metal redox potential. ,,, Thiolates with noninnocent character also serve as good chelators to help stabilize high-valent complexes. One example of this class is the tetradentate-deprotonated TMS PS3H 3 ligand which contains three thiolates and phosphine. − In previous studies, we have demonstrated that treatment of a thiolate-ligated Mn­(I) complex containing a pendant thiol group with O 2 can generate a monomeric O 2 -side-on-bound [PPN]­[Mn IV ( TMS PS3)­(O 2 )] which is metastable in organic solvent and stable in the solid state at ambient temperature (Scheme ). The activation of O 2 is proposed to go through a four-coordinated [Mn II ( TMS PS3)] − intermediate.…”

Iron-Mediated C–C Bond Formation via Reductive Coupling with Carbon Dioxide

“…Having found the {(depe) 2 Fe 0 } fragment capable of reductive C–C bond coupling with CO 2 and C 2 H 4 , its competency in oxalate formation was investigated. Complex 1 was initially targeted because in addition to the design criteria given above, this complex is among only a limited number of isolable transition metal CO 2 complexes, and this stable precoordination may improve the selectivity of reduction. ,− Furthermore, the bending of the CO 2 bond angle upon coordination could lower the potential required for 1-electron reduction ( E 0 = −1.90 V vs NHE) by alleviating the degree of reorganization required in the transition structure . To date, iron-mediated oxalate formation reactions have been exclusively seen at iron­(I) complexes.…”