Fluorine-Containing Tetraarylantimony Carboxylates: Synthesis and Structure

Tetraarylantimony carboxylates Ph4SbOC(O)R (R = CF2Br (I), CF2CF2CF3 (II)), (4‑MeC6Н4)4SbOC(O)CF2CF3 (III), and (4-MeC6Н4)4SbOC(O)CF2CF2CF3 (IV) have been synthesized by the reaction between pentaarylantimony Ar5Sb (Ar = Ph, 4-MeC6H4) and fluorine-containing carboxylic acids. Despite an excess amount of carboxylic acid in the reaction mixture, it does not form any solvates Ar4SbOC(O)R ⋅ HOC(O)R with tetraarylantimony carboxylates. X-ray diffraction shows that the Sb atoms in complexes I–IV have differently distorted trigonal bipyramidal coordination. Crystals of complexes III and IV contain two types of crystallographically independent molecules. The axial СSbO angles in complexes I, II, III, and IV are 175.32(14)°, 178.87(8)°, 178.56(13)° and 178.33(10)°, 178.16(13)°, and 179.58(15)°, respectively. The Sb–O and Sb–С bond lengths are 2.333(3) and 2.106(4)–2.151(5) A in I, 2.340(2) and 2.101(2)–2.154(3) A in II, 2.364(3), 2.411(3), and 2.096(4)–2.159(4) A in III, and 2.376(3), 2.367(3), and 2.105(4)–2.161(4) A in IV. The intramolecular Sb⋅⋅⋅O distances with the carbonyl oxygen atom are 3.506(4) A (I), 3.517(6) A (II), 3.565(6) A (III), and 3.527(6) A (IV), being ~0.2 A smaller than the sum of Sb and O van der Waals radii. The second carbonyl oxygen atoms in crystals of complexes III and IV do not participate in the coordination with the central metal atom.