Halides organocopper compounds

As precursors of the organocopper compounds, organolithium reagents are slightly preferable to organomagnesium halides. 

Finally, pure organocopper compounds have found applications in one-step syntheses of tri- and diorganotin halides. Its has now become well established that treatment of Grignard and organolithium reagents with tin(IV) halides always gives a mixture of products (Eqn. 1 in Scheme 1.14) rather than the desired tri- or diorganotin halides. 

As outlined previously, aggregation of organocopper compounds is a consequence of the fact that the carbon moieties in these compounds are capable of bridging between two copper atoms. It is therefore to be expected that other anionic ligands capable of bridging between metal centers - halides, for example - might easily become incorporated into such aggregates. 

Organocopper compounds such as methyl-, phenyl-, tolyl-, and ethynylcopper are easily isolated by virtue of their insolubility in the media employed in their preparations. Purification is often difficult as lithium and magnesium halides are not readily washed out of the copper compounds by cold ether 82, 214) and because some compounds cling to small quantities of solvent on drying 73, 76, 81). If crystallization does not occur on standing, some copper compounds, such as penta-fluorophenylcopper, may be precipitated as dioxinates after prior removal of lithium and magnesium halides as their dioxinates 34). 

The infrared spectra of many organocopper compounds have been reported (40, 41, 73, 75, 77) and compared favorably with the respective covalently bound organic halides. Bidentate phosphorus ligands coordinate more strongly with arylcopper compounds than monodentate ligands (41, 75, 281e). Substantial modification of the ligand spectrum is also seen in the infrared spectra of arylcopper complexes with bipy-ridyl or 1,10-phenanthroline (41). 

Thermal stabilization of methylcopper by small quantities of magnesium halides has been reported by Costa et al. 82). The stability of ethylcopper is also very dependent on the nature of the magnesium halide present, the iodide having the greatest effect 104). Recent studies indicate that organocopper compounds, RCu, containing metal halides may be cuprates of the type M(RCuX) 190, 191, 257). The presence of... 

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