Crystal structure of bis(benzoato-kappa O)dibutyltin(IV), nBu(2)Sn(bzo)(2)

Abstract

The title compound, [Sn(C4H9)(2)(C6H5COO)(2)], was synthesized in order to study the interaction between di-n-butyltin(IV) oxide and some carboxylic acids. Di-n-butyltin(IV) dibenzoate, nBu(2)Sn(obz)(2), exhibits the same structural features as other diorganotin(IV) dibenzoates characterized by an unsymmetrical bidentate bonding mode [Delta(Sn-O) similar or equal to 0.4 angstrom] of the two benzoate groups to tin. In a first approximation, the coordination sphere at tin resulting from the two stronger bonded O atoms [2.1227 (17) and 2.1405 (16) angstrom] and the two alpha-C atoms of the n-butyl groups [2.125 (3) and 2.129 (2) angstrom] is compressed to a tetragonal disphenoid [<(C-Sn-C) = 148.2 (1)degrees and <(O-Sn-O) = 82.01 (6)degrees]. This coordination sphere is expanded by the less strongly bonded two O atoms [2.507 (2) and 2.485 (2) angstrom] to a substantially distorted octahedron and by a weak intermolecular Sn center dot center dot center dot O interaction [2.943 (2) angstrom] to a pentagonal bipyramid with the formation of centrosymmetric dimers. The unbranched butyl groups adopt two different conformations: anti-gauche [torsion angles: 166.0 (2)-63.9 (4)degrees] and gauche-gauche [65.0 (3)-56.3 (3)degrees]. Intermolecular interactions between the dimers are restricted to O center dot center dot center dot H-C contacts (2.64 angstrom) and van der Waals interactions.