The synthesis, properties, and crystal structure of nBu4N[Rh(CO)2(OAc)2], and the exchange of acetate, chloride, and iodide in nBu4N[Rh(CO)2(X)2]
作者:Anthony Fulford、Neil A. Bailey、Harry Adams、Peter M. Maitlis
DOI:10.1016/0022-328x(91)80168-j
日期:1991.10
Evidence was obtained for the formation of a labile mixed anion [Rh(CO)2I(OAC)]− on reaction of [Rh2(CO)4I2] with nBu4N+ OAc−. It is unlikely that the promotional effect of acetate in methyl acetate carbonylation is due to the participation of acetato-rhodium complexes. Since the lithium acetate reacts readily with iodomethane to give lithium iodide, the observed promotion probably arises from the formation
的反应Ñ卜4 N [RH)CO)2氯2 ],1,用CO下醋酸银,得到二乙酸盐Ñ卜4 N [铑(CO)2(OAc)2,2。该配合物已在光谱上表征[ν(CO term)1986,2066; ν(CO 2-单齿)1615cm -1 ],通过单晶X射线测定。阴离子是平面的,具有单齿乙酸盐,Rh-O 2.074(6)和2.053(7)。配合物2立即与MeI反应生成MeOAc和[Rh(CO)2 I 2 ] -,3,然后通常氧化添加更多的MeI。它还与HCl反应生成HOAC和[Rh(CO)2 Cl 2 ] -。[Rh 2(CO)4 I 2 ]与n Bu 4 N + OAc-反应生成不稳定的混合阴离子[Rh(CO)2 I(OAC)] -的证据。。乙酸盐在乙酸甲酯羰基化中的促进作用不太可能归因于乙酰铑络合物的参与。由于乙酸锂容易与碘甲烷反应生成碘化锂,因此观察到的促进作用可能来自LiI的形成。MeI与n Bu