Nickel(i)-mediated transformations of carbon dioxide in closed synthetic cycles: reductive cleavage and coupling of CO2 generating NiICO, NiIICO3 and NiIIC2O4NiII entities

Abstract

The β-diketiminato nickel(I) complex K₂[L^tBuNi^I(N₂²⁻)Ni^IL^tBu] reacts with CO₂via reductive disproportionation to form CO and CO₃²⁻ containing products, whereas after employment of the Ni^I precursor [L^tBuNi^I(N₂)Ni^IL^tBu] reductive coupling of CO₂ was observed giving an oxalate bridged dinickel(II) complex. The addition of KC₈ to the carbonate and oxalate compounds formed leads to the regeneration of the initial Ni^I complexes in an N₂ atmosphere, thus closing synthetic cycles.