Bis mesityl copper anions

Finally, some organocopper compounds undergo charge disproportionation under the influence of ligands that bind strongly to copper. Treatment of mesityl-copper with l,2-bis-(diphenylphosphino)ethane (DPPE), for example, results in the formation of bis(mesityl)copper anions and a copper cation to which four phosphorus atoms of two DPPE molecules are coordinated [75]. 

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