Reuter Hans, Okio Coco K Y A
Institute of Chemistry of New Materials, University of Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany.
Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carerra 30 No 45-03, Bogotá, Colombia.
Acta Crystallogr E Crystallogr Commun. 2017 Feb 3;73(Pt 3):322-326. doi: 10.1107/S2056989017001505. eCollection 2017 Mar 1.
The asymmetric unit of the title compound, [{Sn(CH)(CHCOO)}O], 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) ring 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 (Sn and Sn ) are trigonal-bipyramidally coordinated. The bond angles between the -butyl groups are widened [135.64 (7)-146.20 (7)°] in comparison with an ideal trigonal bipyramid. Sn-O bond lengths within the {SnO} coordination sphere depend strongly on the position of the corresponding O atom - axial () or equatorial () - as well as on the functionality of the carboxyl-ate groups which exhibit μ (-COO ) and μ (-COO ) coordination modes, respectively. In summary, the following sequence of distances [mean values] is found: (Sn -Oμ) [2.024 (2) Å] < (Sn -Oμ) [2.044 (2) Å] < (Sn -Oμ) [2.158 (6) Å] < (Sn -Oμ-carb) [2.182 (6) Å] < (Sn -Oμ-carb) [2.250 (2) Å] ≃ (Sn -O) [2.247 (12) Å]. The -butyl groups adopt an conformation with exception of two disordered outer -butyl groups of the second mol-ecule which exhibit and conformations. 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 two -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).
标题化合物[{Sn(CH)(CHCOO)}O]的不对称单元由两个半分子组成，通过反演对称性形成完整分子。两个分子均采用此类二聚四有机二锡氧烷二羧酸盐典型的梯形结构，其特征为具有一个中心对称的菱形四元(Sn - O)环，该环在两侧由折叠的六元Sn - O - C环扩展。初步近似来看，两种Sn原子（Sn 和Sn ）均为三角双锥配位。与理想三角双锥相比，丁基之间的键角变宽[135.64 (7) - 146.20 (7)°]。{SnO}配位球内的Sn - O键长强烈依赖于相应O原子的位置——轴向()或赤道()——以及羧酸盐基团的官能团，羧酸盐基团分别呈现μ(-COO )和μ(-COO )配位模式。综上所述，发现以下距离序列[平均值]：(Sn - Oμ) [2.024 (2) Å] < (Sn - Oμ) [2.044 (2) Å] < (Sn - Oμ) [2.158 (6) Å] < (Sn - Oμ - carb) [2.182 (6) Å] < (Sn - Oμ - carb) [2.250 (2) Å] ≃ (Sn - O) [2.247 (12) Å]。除了第二个分子的两个无序外部丁基呈现 和 构象外，丁基均采用 构象。外部羧基的不同O原子与内部以及外部Sn原子之间的弱分子内Sn⋯O相互作用导致这些Sn原子处的八面体配位严重扭曲。单个分子之间的分子间相互作用仅限于范德华力和O⋯H - C相互作用，其中一个分子苯环上的H原子与另一个分子外部非配位C = O基团之间几乎呈线性的非常短的C - H⋯O接触最为突出。它导致分子沿[111]方向呈链状排列。连接到一个分子外部Sn原子的两个丁基在两组位置上无序，占有率分别为0.806 (3)/0.194 (3)和0.702 (3)/0.298 (3)。
