The Oxidative Addition Reaction of Tris(2-Methoxy-5-Chlorinephenyl)Antimony With Trifluoropropionic Acid

The interaction of tris(2-methoxy-5-chlorophenyl)antimony with 3,3,3–trifluoropropionic acid in the presence of hydrogen peroxide (1:2:1 mol) in ether proceeds according to the oxidative addition reaction scheme with the formation of bis(3,3,3-trifluoropropionyl)tris(2-methoxy-5-chlorophenyl)antimony [(MeO-2)(Cl-5)C6H3]Sb[OC(O)CH2F3]2. The IR spectra of compound 2, recorded on a Shimadzu IRAffinity-1S Fourier transform IR spectrometer in a KBr pellet in the region of 4000–400 cm–1, contain absorption bands of carbonyl groups, which are shifted to the low-frequency vibration region in comparison with the IR spectra of the initial acids. According to the X-ray diffraction data obtained on a Bruker D8 QUEST diffractometer, compound 1 has the following crystallographic parameters of the unit cell: crystal size 0.23×0.21×0.08 mm3, space group P21/n, а = 8.883(7), b = 21.184(15), c = 13.642(15) Å, α = 90.00°, β = 107.34(3)°, γ = 90.00°, V = 2451(4) Å3, ρcalc = 1.587 g/cm3, Z = 4; crystal 2 has the following crystallographic parameters of the unit cell: 0.3×0.25×0.08 mm3, P21/c, а = 12.00(5), b =16.81(7), c =16.30(9) Å, α =90.00°, β =108.3(3)°, γ =90.00°, V =3121(25) Å3, ρcalc = 1.704 g/cm3, Z = 4. The antimony atom in 2 has a distorted trigonal-bipyramidal coordination with carboxylate ligands in axial positions. The OSbО angles are 174.2(5)°, the sums of the СSbC angles in the equatorial plane are 360°, the axial Sb–O bonds equal 2.073(15), 2.092(15) Å, and the equatorial Sb–С bonds equal 2.05–2.13 Å, which is close to the sum of the covalent radii of the atoms. The intramolecular Sb∙∙∙OМе distances (3.035(3), 3.037(3), 2.992(4) Å (1), 3.03(2), 3.119(17), 3.147(19) Å (2)), as well as Sb∙∙∙OMe for compound 2 (3.232(19), 2.99(2) Å), are much smaller than the sum of the van der Waals radii of atoms.