Synthesis and structural characterization of some complexes of hexa-coordinated antimony

The oxidation of triphenylantimony and triphenylphosphine by tert-butylhdro peroxide in the presence of catechol gives a new complex of a hexa-coordina ted antimony, (C6H4O2)SbPh3(OPPh3).(7) In this complex triphenylphosphine o xide plays the role of the sixth ligand in a coordination sphere of an anti mony atom of triphenylantimony o-phenylenedioxide. The compound was charact erized by IR, H-1 NMR, C-13 NMR, P-31 NMR and X-ray single-crystal diffract ion method. Crystal data for 7 at T = 293 K: a = 21.111(1) Angstrom, b = 13 .910(4) Angstrom, c = 25.052(8) Angstrom, beta = 96.48(3)degrees, V = 7310( 4)(4)Angstrom(3), Z = 8, D-calc = 1.380 g/cm(3), mu = 0.839 mm(-1), space g roup C2/c. The geometry of the antimony atom in the synthesized complex is a distorted octahedron. Sixth coordination Sb-O(P)-2.33 Angstrom - is compa rable with the sum of covalent radii of antimony and oxygen atoms, 2.20 Ang strom. Five analogous complexes containing trimethyl(triethyl)antimony o-ph enylenedioxide or 2.2.2-triphenyl-1.3.2-dioxastibolane and triphenylphosphi ne oxide or triphenylantimony o-phenylenedioxide and dimethylsulfoxide or p yridine oxide as a monodentate ligand were synthesized in the same manner. These compounds were also characterized by IR, H-1 C-13 and P-31 NMR.