Figure 6.

Catalytic cycle of copper complex for CO₂ activation as proposed by Bouwman and co‐workers. The initial copper(II) complex [4]⁴⁺ is first reduced at −0.03 V vs. NHE to the copper(I) complex [1]²⁺. This is subsequently reduced by two CO₂ to copper (ii) again. Two of the complexes merge and the bound CO₂ ^.− radical anions couple to form bridging oxalate molecules [2]⁴⁺. Lithium ions and acetonitrile liberate the oxalate as lithium oxalate and the initial complex is formed again. Reproduced with permission from Ref. [153]. Copyright 2010, American Association for the Advancement of Science.