Synthesis and structure of tris(2-metoxy)(5-bromo)phenylantimony bis[3,5-dinitrobenzoate] solvate [C6H3(2-OMe)(5-Br)]3Sb[OC(O)C6H3(NO2)2-3,5]2 • PhH • 1/2 C8H18

Tris(2-methoxy)(5-bromo)phenylantimony bis[3,5-dinitrobenzoate] (1) was obtained from 3,5-dinitrobenzoic acid by oxidative addition to triarylantimony in the presence of tertiary butyl hydroperoxide in ether, and was isolated by recrystallization from a benzene-octane mixture in the form of a crystal solvate with benzene and octane molecules in its crystal lattice. The structure of solvate 1 was established by the IR spectroscopy and X-ray diffraction analysis (XRD). In the IR spectrum of complex 1, in addition to the absorption bands related to the stretching vibrations of the Sb-C, СAr-О-Ме, and carbonyl groups, there are bands corresponding to the stretching vibrations of the C-Br bonds (524 and 555 cm-1). The X-ray diffraction data show that the antimony atoms in complex 1 have a distorted trigonal bipyramid coordination with carboxylate ligands in the axial position. The antimony atom and two oxygen atoms do not lie on the same straight line and are located in such a way that the OSbO angle is 170.79°. The O…Sb distances (2.134(4) and 2.110(5) Å) are close to the sum of the covalent radii of antimony and oxygen. In addition, according to the X-ray diffraction data, compound 1 crystallizes in the monoclinic crystal system, space group P21/n. The structural organization in the crystal is formed due to short contacts of oxygen atoms in the nitro groups of the carboxylate ligands with carbon and bromine atoms of the aryl ligands of neighboring molecules, as well as hydrogen O...H (2.524-2.715 Å) bonds. In addition, a certain contribution to the formation of the crystal structure is made by the p-p stacking between the aromatic rings of crystallization benzene and the methoxy-bromo-phenyl ligands. The aromatic rings are displaced in relation to each other and the distance between them is 3.367 Å. Melting point of solvate 1 is 172.6 °C, according to the thermal analysis data. However, further increase in temperature is accompanied by decomposition of compound 1, and therefore an exothermic peak is observed on the DSC curve at 255.7 °C, corresponding to a mass loss of 31 % according to the TGA data. Complete tables of atom coordinates, bond lengths, and valence angles are deposited at the Cambridge Crystallographic Data Center (No. 2060562, deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif)