Oxidation of tris(2-methoxy-5-bromophenyl)antimony by tert-butylhydroperoxide in the presence of compounds containing a mobile hydrogen atom

Oxidation of tris (2-methoxy-5-bromophenyl)antimony with tertiary butylhydroperoxide in the presence of water, benzoic acid, 2,6-dihydroxybenzoic acid and 2-chloro-4-fluorophenol in diethyl ether leads to formation of tris (2-methoxy-5-bromophenyl)antimony oxide (1), tris (2-methoxy-5-bromophenyl)antimony dibenzoate (2), m-oxo[ hexakis (2-methoxy-5-bromophenyl)- bis (2,6-dihydroxybenzoato)diantimony] (3), m-oxo[ hexakis (2-methoxy-5-bromophenyl)- bis (2-chloro-4-fluorophenoxo)diantimony] (4), respectively. The compounds have been identified by X-ray diffraction analysis. According to the X-ray diffraction data, the crystal of solvate 1 with chloroform consists of centrosymmetric binuclear molecules containing the Sb2O2 cycle with tetragonal coordination of the antimony atoms (the Sb-O bond lengths are 1.961(4) and 2.041(5) Å, the Sb-C distances are 2.114(6)-2.153(6) Å). In solvate 2 with benzene the antimony atoms have a distorted trigonal-bipyramidal coordination with the oxygen atoms of carboxylate ligands in axial positions (Sb-O 2.075(4), 2.105(4) Å), the carbonyl oxygen atoms are coordinated with the central metal atom (Sb∙∙∙O=C 3.023(6), 3.077(8) Å), the Sb-C bond lengths (2.104(5)-2.112(5) Å) are significantly less than in 1. The ranges of variation in the Sb-C bond lengths in the practically linear binuclear molecule of solvate 3 with acetonitrile are 2.101(5)-2.106(5) and 2.100(5)-2.104(5) Å (the SbOSb angle equals 178.05(18)°). The bond lengths of antimony atoms with the bridging oxygen atom (1.925(4), 1.936(4) Å) are less than the sum of the covalent radii of antimony and oxygen, as well as the distances between the antimony atom and the terminal carboxyl ligand (Sb-O 2.263(4), 2.214(4) Å). The carbonyl oxygen atoms are coordinated with the central metal atom (Sb∙∙∙O=C 3.484(8), 3.512(9) Å) to a lesser extent than in 2. The crystal of solvate 4 with benzene contains two types of crystallographically independent corner molecules (the SbOSb angles are 163.75(18)°, 164.27(19)°), the difference in lengths of the Sb-Obridge (1.939(11)-1.981(13) Å) and Sb-Oterm (2.096(11)-2.208(11) Å) is not as sharp as in the case of complex 3. Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center (No. 2070383 (1); No. 2074511 (2); No. 1970910 (3); No. 2064392 (4); deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).