Synproportionation reactions between copper(II) trihalogenoacetates Cu(CX3CO2)(2), X = F, Cl or Br, and copper in the presence of carbon monoxide

摘要

The trichloro- and tribromo-acetato derivatives of copper(II) of general formula Cu-2(CX3CO2)(4)(CX3CO2H)(2) have been prepared by exchange reactions from Cu(CF3CO2)(2) and CX3CO2H (X=Cl or Br) in a hydrocarbon solvent. The chloro derivative, which has also been obtained from CuO in the presence of CCl3CO2H/(CCl3CO)(2)O, has been characterized by variable-temperature magnetic measurements and by X-ray diffraction. The trifluoroacetato carbonyl derivative of copper(I), Cu(CF3CO2)(CO), has been prepared: (a) by reaction of Cu2O with CF3CO2H/(CF3CO)(2)O in the presence of CO; (b) by direct carbonylation of Cu(CF3CO2) in toluene or in the solid state; (c) by synproportionation of Cu(CF3CO2)(2) and copper in the presence of CO in MeOH, DME, THF or toluene at room temperature. Solutions of Cu(CCl3CO2)(CO) have been obtained by the synproportionation of Cu-2(CCl3CO2)(4)(CCl3CO2H)(2) and copper under a CO atmosphere in toluene. No carbonyl derivative was observed in solution with Cu-2(CBr3CO2)(4)(CBr3CO2H)(2) under similar conditions. On standing, hydrocarbon solutions of Cu(CCl3CO2)(CO) slowly gave CuCl(CO) and a mixed-valence, polynuclear carbonyl derivative of formula [Cu-4(CCl3CO2)(6)(CHCl2CO2H)(CO)(2)](n) which has fully been characterized by variable temperature magnetic measurements and by X-ray diffraction. [References: 69]