'Higher-Order' Cyanocuprates - Are They Real?.

sup 13C NMR studies of cuprates prepared from 2 equiv of organolithium reagent RLi and CuI or CuCN establish that they are both essentially monomeric "ate" complexes [RCuR] sup - Li sup + in THF. It had been believed that the cuprates from CuCN were special "higher order" species R sub 2 Cu(CN)Li sub 2. R = Ethyl was chosen as a typical alkyl reagent and R = Phenyl as a typical aryl reagent. The behavior of the cuprates in the presence of HMPA and 12- crown-4 provides additional evidence for our conclusion.