The minor product [Ph3Sb(Cl)O]3C x PhH in the ligand redistribution reactions of pentavalent antimony aryl derivatives

One of the reaction products of triphenylantimony dichloride and triphenylantimony bis (2,4-dibromophenoxide) (1:1 mol.) in benzene in air is the compound of three-coordinated carbon [Ph3Sb(Cl)O]3C × PhH (1). The compound has been identified by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction analysis the target product is a benzene solvate [C61H51Cl3O3Sb3, M = 1303.65; the monoclinic system, space group P21/c; a 17.17(2), b 18.75(2); c 17.322(18) Å; α 90.00, β 90.58(5), γ 90.00 rpaд.; V 5576(11) Å3; Z 4; µ 1.630 mm-1; F (000) 2580.0; crystal size 0.28 × 0.22 × 0.11 mm; 2θ for data collection 6.4 - 36.8 degrees; index ranges -15 ≤ h ≤ 15, -16 ≤ k ≤ 16, -15 ≤ l ≤ 15; total reflections 24392; independent reflections 3981; Rint 0.0516; variables 632, GOOF 1.141; R 1 = 0.0392; wR 2 = 0.0912; residual electron density 0.43/-0.35 e/Å3]. The COSb angles in the compound 1 vary in the interval 123.3(8)-127.1(8)°. The C-O shortened distances (1.365(15)-1.385(15) Å) compared to the sum of the covalent radii of carbon and oxygen atoms (1.51 Å) indicate an increase in the multiplicity of these bonds. The abnormal reduction of Sb-O distances (1.986(7), 2.001(7), 2.011(7) Å) in the neutral molecule 1 compared to the sum of the covalent radii of antimony and oxygen atoms (2.14 Å) implies delocalization of the electron density in the CO3Sb3 core. The Sb - Cl distances are slightly longer than the sum of the covalent radii of antimony and chlorine atoms and are longer than ones in triphenylantimony dichloride. The antimony atoms have a distorted trigonal-bipyramidal coordination with heteroatoms in axial positions. The formation of the crystal structure is due to the formation of weak hydrogen bonds such as C···H (2.72-2.90 Å) and Cl···H (2.94 Å). Complete tables of coordinates of atoms, bond lengths and valence angles are deposited at the Cambridge Structural Data Bank (No. 1851485; deposit@ccdc.cam.ac.uk; http:// www.ccdc.cam.ac.uk/data_request/cif). Keywords: triphenylantimony dichloride, triphenylantimony bis(2,4-dibromophenoxide),