Synthesis and structure of bis(thiophene-2-aldoximato)-tris(5-bromo-2-methoxyphenyl)antimony

Synthesis of bis (thiophene-2-aldoximato) tris (5-bromo-2-methoxyphenyl)antimony (1) has been carried out by the oxidative addition reaction of tris (5-bromo-2-methoxyphenyl)antimony with thiophene-2-aldoxime in the presence of tert -butyl hydroperoxide with the 1:2 molar ratio of the reactants. The compound has been characterized by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction analysis data, in the crystal there are two types of crystallographically independent the molecules, geometrical parameters of which are slightly different. Coordination polyhedron of antimony atoms in a molecule is a distorted trigonal bipyramid. The sum of the СSbC angles equals 360°, the values of the individual angles differ from the theoretical 120° by no more than 8.6(8)°. The axial OSbO angle is 175.8(4)°. The OSbC angles vary within the range 85.8(6)º-97.6(6)º. The average value of the Sb-C bond lengths is 2.13(2) Å. The Sb-O distances equal 2.08(1) Å. The distances between the Sb atom and N atoms of the iminoxy groups are 2.80(2)-2.94(2) Å. The distances between the N and O atoms do not depend on the distances between the Sb and N atoms; they are equal to 1.39(2)-1.43(2) Å. In the molecules there are contacts between the Sb and O atoms of methoxy groups, the corresponding distances are within the range of 3.13(1)-3.23(1) Å. The molecules in a crystal are connected by intermolecular hydrogen bonds between the aromatic H and Br (2.883 Å), S (2.992 Å) and N (2.715 Å) atoms. In the molecules there are intramolecular short contacts between the iminoxy group O atom and S (2.72(1)-2.80(1) Å), as well as the methoxy group O atom (2.93(2)-3.03(2) Å).