Synthesis and structure of µ2-oxo-bis [(pentafluoropropionato)-tris(5-bromo-2-methoxyphenyl)antimony]

The synthesis of μ2-oxo- bis [(pentafluoropropionato) tris (5-bromo-2-methoxyphenyl)antimony] (1) has been curried out by the oxidative addition reaction of tris (5-bromo-2-methoxyphenyl)antimony with pentafluoropropionic acid in the presence of hydrogen peroxide at an equimolar ratio of reactants. The compound is characterized by IR spectroscopy and X-ray diffraction analysis. According to X-ray diffraction data, there are two types of crystallographically independent molecules with slightly different geometrical parameters in the crystal. The antimony atoms in each molecule are linked by the bridging oxygen atom (the SbOSb angle is 167.6(7)°). The trigonal bipyramidal coordination of antimony atoms is distorted; the axial OSbO angles are 175.9(4)°, 174.5(4)° for Sb(1) and Sb(2) atoms, respectively. The sums of valence CSbC angles in the equatorial planes are 359.6(6)° and 356.4(6)°. The mean values of the Sb(1)-C and Sb(2)-C bond lengths are 2.12(2) Å, the Sb-O( μ 2) distances are 1.89(1), 1.98(1) Å. The carboxylate ligands in each molecule are monodentate. The distances between the antimony atoms and the corresponding terminal oxygen atoms are 2.22(1), 2.39(1) Å, the Sb···O=C distances are 3.38(2), 3.71(1) Å. The d(Sb···O=C)/d(Sb-О) ratios, which can be used to estimate the asymmetry of the ligand related to metal atom coordination, are 1.67 and 1.41. In crystal 1 there are such contacts as Sb···OMe (2.88(1)-3.16(1), 3.01(1)-3.20(1) Å), hydrogen bonds involving halogen atoms H···F (2.16, 2.50, 2.58 Å), H···Br (2.92, 2.96, 3.04 Å) and carbonyl oxygen atoms H···О (2.43, 2.59 Å), as well as halogen···halogen F···F interactions (2.70, 2.71 Å).