Structure of organic and organoelemental compounds. Part 6

Tetraphenylantimony carboxylates Ph4SbOC(O)R (R=CHF2 (1), CF2CF2CF3 (2), C6H4Cl-2 (3), C6H4Br-3 (4), C6H3F2-2,5 (5), C6H3F2-2,3 (6), C6F4H (7), C6F5 (8) have been synthesized by the interaction of equimolar amounts of pentaphenylantimony with carboxylic acids in benzene; their structures have been characterized. In these carboxylates, the antimony atoms have a distorted trigonal-bipyramidal coordination with the oxygen atom of carboxyl groups in the axial position. The presence of a coordination bond between the central atom and carbonyl oxygen atom suggests an increase in the coordination number of the antimony atom to 6. Analysis of the structural data of tetraphenylantimony carboxylates shows that the distortion of the trigonal-bipyramidal configuration of molecules 1-8 manifests itself to varying degrees. The C=O bond lengths (1.197(3)-1.284(7) Å) are shorter than the C-O bond lengths (1.196(18)-1.231(8) Å), while the lengths of double bonds in carboxylic acids are (1.226-1.229 Å). The Sb-C distances in molecules 1-8 are in the range of 2.095(6)-2.167 Å, and the Sb-Cax distance (2.154(3) Å (2) - 2.174(4) Å (5)) is higher than the Sb-Ceq equatorial bonds. In addition, there are intramolecular contacts between the antimony atom and the carbonyl oxygen (3.100(5) Å (5) - 3.517(6) Å (2)), which is less than the sum of the van der Waals radii of these atoms (3.700 Å). The maximum equatorial angle on the side of the Sb∙∙∙O=C contact (120.7(2)°-130.67(14)°) is less than the other two equatorial angles. Complete tables of atomic coordinates, bond lengths and valence angles have been deposited with the Cambridge Crystallographic Data Centre (No 2115014 (1), 1876829 (2), 2214913 (3), 2214921 (4), 2115013 (5), 2233398 (6), 1919918 (7), 1821410 (8); deposit@ccdc.cam.ac.uk; http://www.ccdc.cam.ac.uk).