Bis(μ-benzoato-κ2O:O')bis-(benzoato-κO)octabutyldi-μ3-oxido-tetra-tin(IV).
The asymmetric unit of the title compound, [{Sn(C4H9)2(C6H5COO)}2O]2, consists of two half molecules, completed by application of inversion symmetry. Both mol-ecules adopt a ladder structure typical for this class of dimeric tetra-organodistannoxane di-carboxyl-ates characterized by a centrosymmetric four-membered (Sn-O)2ring of rhomboidal shape that is extended on both sides by folded six-membered Sn-O-C rings. To a first approximation, both kinds of Sn atoms (Sniand Sno) are trigonal-bipyramidally coordinated. The bond angles between then-butyl groups are widened [135.64 (7)-146.20 (7)°] in comparison with an ideal trigonal bipyramid. Sn-O bond lengths within the {R2SnO3} coordination sphere depend strongly on the position of the corresponding O atom - axial (ax) or equatorial (eq) - as well as on the functionality of the carboxyl-ate groups which exhibit μ2(-COOi) and μ1(-COOo) coordination modes, respectively. In summary, the following sequence of distances [mean values] is found:d(Sno-Oμ3)eq[2.024 (2) Å] <d(Sni-Oμ3)eq[2.044 (2) Å] <d(Sni-Oμ3)ax[2.158 (6) Å] <d(Sno-Oμ1-carb)ax[2.182 (6) Å] <d(Sni-Oμ2-carb)ax[2.250 (2) Å] ≃d(Sno-Oμ2-carb)ax[2.247 (12) Å]. Then-butyl groups adopt ananti-anticonformation with exception of two disordered outern-butyl groups of the second mol-ecule which exhibitgauche-antiandanti-gaucheconformations. Weak intra-molecular Sn⋯O inter-actions between the different O atoms of the outer carboxyl groups with the inner, as well as outer, Sn atoms give rise to a strongly distorted octa-hedral coordination at these Sn atoms. Inter-molecular inter-actions between the individual mol-ecules are restricted to van der Waals and O⋯H-C inter-actions of which a nearly linear very short C-H⋯O contact between the H atom of the phenyl group of one of the mol-ecules with the outer non-coordinating C=O group of the other molecule is the most prominent. It gives rise to a chain-like arrangement of the mol-ecules along [111]. The twon-butyl groups attached to the outer Sn atom of one mol-ecule are disordered over two sets of sites with occupancies of 0.806 (3)/0.194 (3) and 0.702 (3)/0.298 (3).
Institute of Chemistry of New Materials, University of Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany.
Hans
H
Reuter
Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carerra 30 No 45-03, Bogotá, Colombia.
Coco K Y A
CK
Okio
crystal structure; di­carboxyl­ate; ladder structure; tetra­organodistannoxane