Unusual reaction of triphenylantimony with 2,3-difluorobenzoic acid in the presence of tert-butyl hydroperoxide

The interaction of triphenylantimony with 2,3-difluorobenzoic acid in the presence of tert-butyl hydroperoxide (molar ratio 1:2:1) in ether yielded 12 % tetraphenylantimony 2,3-difluorobenzoate (1), which was identified by IR spectroscopy and X-ray structural analysis. X-ray diffraction analysis was performed on a D8 QUEST diffractometer from Bruker. The crystallographic characteristics of the unit cell of the compound are as follows: space group P-1, a = 9,859(6), b = 10,180(6), c = 14,332(9) Å, α = 84,15(2)°, β = 83,09(2), γ = 68,56(4)°, V = 1326,6(14) Å3, Z = 2, ρcalc = 1,470 g/cm3, m = 2,079 mm-1, F(000) = 588.0, crystal size 0,32×0,2×0,09 mm, data collection range for 2θ deg: 5,74-61,36, index range -14 ≤ h ≤ 14, -14 ≤ k ≤ 14, -20 ≤ l ≤ 20, number of measured reflections 83031, number of independent reflections 8118, Rint = 0,0387, GOOF = 1,037, number of parameters 325, R1 = 0,0287, wR2 = 0,0597. According to X-ray diffraction data, the antimony atoms in the compound have a distorted trigonal-bipyramidal coordination with the oxygen atom of the carboxylate group in the axial position. The axial angle СSbO is 177,90(5)º. The sum of the equatorial angles CSbC is 357,04(9)°, the Sb-Ceq distances [2,119(2), 2,124(2), 2,126(2) Å] are significantly shorter than the Sb-Sax [2,164(2) Å] and Sb-O [2,2799(18) Å] bond lengths. The organization of molecules in the crystal of compound 1 is due to hydrogen bonds and C∙∙∙H π-interactions of the rings of the aryl and carboxyl ligands. Complete tables of atomic coordinates, bond lengths, and bond angles have been deposited with the Cambridge Crystallographic Data Center (No. 2217060; deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).