Copper, organo- compounds structure

The difficulties of direct oxidative insertion with metals other than Mg or Li mean that o-complexes are often made from organo-lithium or Grignard reagents by metal exchange. This reaction amounts to a nucleophilic substitution at the metal without a change of oxidation state so the metal is used in whatever oxidation state is finally needed. Attack of methyl lithium on a Cu(I) halide gives methyl copper 50, a o-complex of Me- and Cu(I). If an excess of MeLi is present an ate complex is formed, lithium dimethylcuprate 51. This is formally a compound of a copper anion 51a, just as BF4 is a borate. The term ate complex refers to such formally anionic complex in which the metal has one extra anionic ligand. Its true structure is dimeric 51b and it exists as an equilibrium with 52 in solution.20... 

Organo-copper compounds are important for the (C-C)-connection. In the solid state such copper compounds can exist as linear polymer. An example is the cyanocuprat [2-(Me2NCH2)(C6H4)2CuLi2(CN)(THF)4] c structured as polymeric chain with alternating cuprat-anions (Ar2Cu) and cations (LiCNLi) [315,316], 2,4,6-Tris[4-pyridyl)-methyl-sulfanyl]-l,3,5-triazine forms with Ag a one-dimensional chain polymer with nanometer tubes 73a (M = Ag(II)) [317], These tubes are connected via Ag-N and Ag-S bonds to linear chains 73b. Other comparable polymers are mentioned in [317]. 

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