Synthesis and structural features of tris(5-bromo-2-methoxyphenyl)antimony dicarboxylates

Tris(5-bromo-2-methoxyphenyl)antimony bis(4-nitrophenylacetate) (I), tris(5-bromo-2-methoxyphenyl)antimony bis(2-methoxybenzoate) (II), and tris(5-bromo-2-methoxyphenyl)antimony bis(phenylpropiolate) (III) have been synthesized via the reaction between tris(5-bromo-2-methoxyphenyl) antimony and 4-nitrophenylacetic acid, 2-methoxybenzoic acid, and phenylpropiolic acid, respectively, in the presence of hydrogen peroxide (molar ratio: 1: 2: 1). According to X-ray diffraction data, the antimony atom in molecules of complexes I–III has a distorted trigonal bipyramidal coordination. The OSbO axial angles and the CSbC bond angles in the equatorial plane are 173.27(15)°, 172.96(11)°, 172.99(10)°, and 115.5(2)°–123.3(2)°, 108.81(16)°–129.32(17)°, and 110.66(17)°–127.91(17)°, respectively. The Sb-O bond lengths are 2.092(4) and 2.115(4)Å in I, 2.088(3) and 2.097(2) Å in II, and 2.096(3) and 2.120(3) Å in III. The Sb-C bonds range within 2.095(6)–2.123(6) Å in I, 2.107(4)–2.117(4) Å in II, and 2.097(4)–2.116(4) Å in III. Complexes I, II, and III are observed to have intramolecular Sb…OCH₃ contacts (3.169–3.226, 3.134–3.174, and 3.147–3.196 Å, respectively) in addition to Sb…O=C interactions (3.121, 3.139Å; 2.944, 3.038 A0; 3.111, 3.120 Å).