Synthesis, and crystal and molecular structures of the triflato and trifluoroacetato complexes of zinc, Zn(O3SCF3)2(DME)2 and [Zn(O2CCF3)2(DME)]n

Anhydrous Zn(O3SCF3)2 and Zn(O2CCX3)2, X=F, Cl, Br were obtained in substantially quantitative yields from ZnO (or ZnEt2 in the case of the bromide derivative) and a mixture of the corresponding acid and anhydride in heptane as medium. The reactions are rapid and moderately exothermic. Recrystallization of the triflate and trifluoroacetate complexes from dimethoxyethane (DME) produced single crystals of Zn(O3SCF3)2(DME)2 (1) and [Zn(O2CCF3)2(DME)]n (2) suitable for X-ray diffraction studies. In both compounds zinc is hexacoordinated with a pseudo-octahedral geometry. Compound 1 is constituted by mononuclear molecules with terminal monodentate O3SCF3 ligands in trans position. A polynuclear chain structure was found for 2 with zinc atoms joined alternatively by triple and single carboxylato bridges, and with bidentate terminal DME.