Synthesis and Structural Features of Carboxylate Tetra(para-tolyl)antimony p-Tol4SBoc(O)Ar, Ar = C6H3(NO2)2–3.5, C6H4Br-3, C6H4I-4

Tetraphenylantimony carboxylates, p-Tol4SbOC(O)Ar, where Ar = C6H3(NO2)2–3.5 (1), C6H4Br-3 (2), and C6H4I-4 (3) were synthesized by reacting equimolar amounts of penta(p-tolyl)antimony with carboxylic acid in benzene at room temperature. X-ray diffraction studies performed at 293 K on a D8 Quest Bruker automatic four-circle diffractometer (equipped with a two-coordinate CCD detector, MoKα radiation, λ = 0.71073 Å, and a graphite monochromator) revealed that the antimony atoms in the crystals 1 [C35H31N2O6Sb, M = 697.38; monoclinic, symmetry group P21/n; cell parameters: a = 10.248(7) Å, b = 10.801(7) Å, c = 29.10(2) Å; α = 90°, β = 92.60(3)°, γ = 90°; V = 3218(2) Å3; crystal size 0.4 × 0.31 × 0.07 mm; reflection index ranges: –13 ≤ h ≤ 13, –13 ≤ k ≤ 13, –37 ≤ l ≤ 37; total reflections: 105 827; independent reflections: 7128; Rint = 0.0415; GOOF = 1.061; R1 = 0.0250, wR2 = 0.0564; residual electron density 0.41/–0.61 e/Å3], 2 [C35H32O2BrSb, M = 686.27; triclinic, symmetry group P $$\bar {1}$$ ; cell parameters: a = 10.114(7) Å, b = 11.548(6) Å, c = 13.889(9) Å; α = 99.16(3)°, β = 94.63(3)°, γ = 107.97(3)°; V = 1508.7(17) Å3; crystal size: 0.48 × 0.4 × 0.32 mm; reflection index ranges: –17 ≤ h ≤ 17, –19 ≤ k ≤ 19, –23 ≤ l ≤ 23; total reflections: 97 427; independent reflections: 15 399; Rint = 0.0506; GOOF = 1.015; R1 = 0.0454, wR2 = 0.0936; residual electron density 0.89/–1.55 e/Å3], 3 [C35H32O2SbI, M = 733.26; triclinic, symmetry group P $$\bar {1}$$ ; cell parameters: a = 10.008(6) Å, b = 11.472(7) Å, c = 15.534(9) Å; α = 68.92(3)°, β = 85.72(3)°, γ = 70.37(2)°; V = 1565.4(15) Å3; crystal size: 0.43 × 0.28 × 0.09 mm; reflection index ranges: –14 ≤ h ≤ 13, –16 ≤ k ≤ 16, –22 ≤ l ≤ 22; total reflections: 85 719; independent reflections: 10 417; Rint = 0.0295; GOOF = 1.036; R1 = 0.0366, wR2 = 0.0933; residual electron density 1.18/–2.19 e/Å3], exhibit distorted trigonal-bipyramidal coordination with carbon and oxygen atoms in the axial positions (axial angles: 174.83(6)° for 1, 174.44(6)° for 2, 178.86(8)° for 3). The Sb–O bond lengths are 2.3469(17) Å for 1, 2.2984(18) Å for 2, and 2.277(2) Å for 3. The Sb–C bond lengths vary within a narrow range (2.113(2)–2.152(2) Å for 1, 2.104(2)–2.171(2) Å for 2, 2.111(2)–2.161(3) Å for 3). The structural arrangement in crystal 1 is governed by weak intermolecular C=O…H (2.58 Å) and NO…H (2.58–2.63 Å) contacts. In crystal 2, Br…H (2.95 Å) and C=O…Sb (3.080 Å) contacts are present. In crystal 3, the carbonyl oxygen atom is weakly coordinated to the metal atom (C=O…Sb 3.470 Å). Full tables of atomic coordinates, bond lengths, and bond angles for the structures are deposited with the Cambridge Crystallographic Data Center (CCDC Nos. 2213730 for 1, 2221986 for 2, 2222094 for 3; [email protected]; Cambridge Crystallographic Data Centre).