Unsolvated homo- and heterometallic highly fluorinated β-diketonate complexes of copper(II)

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The unsolvated Cu(II) complex with bis(pentafluorobenzoyl)methanide ligand (L, C6F5COCHCOC6F5−) is prepared and crystallized as [CuL2] (1) using gas phase sublimation-deposition at 150 °C. The X-ray crystallographic characterization confirmed the centrosymmetric mononuclear structure of 1 with a square planar geometry around Cu(II) (Cu–Oav 1.9149(8) Å). The reaction of 1 with sodium hexafluoroacetylacetonate [Na(hfac)] in a solvent-free environment afforded [Na2Cu2L4(hfac)2] (2), the first heterometallic Na–Cu β-diketonate characterized by single-crystal X-ray diffraction. In the centrosymmetric tetranuclear structure of 2, a dimeric [Na(hfac)]2 unit is sandwiched between two CuL2 units. The L-ligands function as chelating-bridging between Cu and Na through one of their O-atoms. The hfac ligands are chelating-bridging between Cu and Na and between Na(1) and Na(1A) through both O-atoms. In addition to the five primary Na–O interactions (av. 2.4109(17) Å), three secondary Na–F contacts (av. 2.6006(15) Å) contribute to the overall distorted square antiprismatic coordination environment for Na. The geometry of Cu is square pyramidal with Cu–O(L) distances averaging at 1.922(14) Å and Cu–O(hfac) of 2.3021(15) Å. Thermal decomposition of 2 yields a mixture of NaCuF3, Na2CuF4 and NaF, when conducted at 230 °C in argon at ambient pressure.