CRYSTAL AND MOLECULAR-STRUCTURE OF RO-5-METHOXY-5-METHYL-2,4-HEXANEDIONATO)COPPER(II)

A combined X-ray diffraction study of the single crystals (Enraf-Noniu s CAD-4 automatic diffractometer, MoKalpha radiation, graphite monochr omator) and polycrystals (DRON-UM1, CuKalpha radiation, Ni filter) of a new volatile complex of Cu(II) obtained from fluorinated alkoxy-beta -diketone, CF3CO-CH2-CO-C(CH3)(2)OCH3, is reported. The compound has a molecular structure; the crystals consist of trans-bis(1,1, ro-5-meth oxy-5-methyl-2,4-hexanedionato)copper(II) complexes. The structure was refined anisotropically for 2314 independent reflections with I > 2 s igma(I) to R = 0.069. Crystal data: a = 24.469(3), c = 10.581(2) Angst rom, V = 5486.4 Angstrom(3), space group R (3) over bar, Z = 9, d(calc ) 1.17 g/cm(3). The complexes are packed to form through channels simi lar to 5 Angstrom in diameter along the c axis, with terminal fluorine atoms facing the channels. The crystal-chemical data of the compound are compared with those of the nonfluorinated analog, -methoxy-2,6,6-t rimethylheptane-3,5-dionato)copper (II). The introduction of CF3 group s into alkoxy-beta-diketone considerably decreases the sublimation tem perature of the complex. The geometrical characteristics of chelate no des in the complexes are almost equal: the Cu-O distances are 1.92 Ang strom and the O-Cu-O bond angles 92.1 degrees (average). In both cases , the square planar environment of the Cu atom is completed to bipyram idal by interactions with the oxygen atoms of the methoxy groups of th e neighboring molecules, with Cu ... O distances being 2.8 Angstrom.