Organocopper compounds crystallization

Since isolable organocopper) 11) compounds do not apparently exist, it is rather surprising that oxidation of the cuprate CdI+[(CF3)2Cu ] (prepared in situ) with thiuram disulfide affords (CF3)2Cu "S2CNEt2 (see Eqn. 1 in Scheme 1.6), the first and so far only example of an organocopper compound with the copper atom in the trivalent oxidation state. The structure of this compound was unambiguously proven by an X-ray crystal structure determination (see Fig. 1.2) [37]. 

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). 

Conjugate addition of organocopper reagents to a molybdenum n-allyl enone compounds 146 was investigated. Similar to CpFeCCOjPPhjCr] -enone) - and Cr(CO)3(l-enone-2-OR-benzene), s-cis(CO/C=C) enone conformer 146a occurs in the crystal structure according to X-ray measurements and is also the major dissolved species in equilibrium with... 

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