Synthesis and Structure of Bis(thiophene-2-aldoximato)-tris(5-bromo-2-methoxy-phenyl)antimony

Abstract

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).