Nithya C, Sithambaresan M, Kurup M R Prathapachandra
Department of Applied Chemistry, Cochin University of Science and Technology, Kochi 682 022, India.
Department of Chemistry, Faculty of Science, Eastern University, Chenkalady, Sri Lanka.
Acta Crystallogr E Crystallogr Commun. 2016 Jan 20;72(Pt 2):199-202. doi: 10.1107/S205698901600058X. eCollection 2016 Feb 1.
The title compounds, C15H12Br2OS2, (I), and C20H15BrOS, (II), were synthesized by employing Claisen-Schmidt condensation of pentan-3-one and di-benzyl-acetone with 5-bromo-thio-phene-2-carbaldehyde in the presence of methano-lic KOH. Even though 1:2 products were expected in both of the reactions, 1:2 and 1:1 products were obtained as (I) and (II), respectively. In (I), the two methyl groups are trans to each other, 29.5 (7) and 28.7 (7)° away from the central carbonyl bond between them, whereas the two phenyl rings of di-benzyl-acetone subtend a dihedral angle of 53.09 (18)°. In the crystal of (I), C-H⋯O hydrogen bonds define mol-ecular chains along c. A second type of mol-ecular chain is formed along b by means of C-Br⋯π inter-actions. These two families of mol-ecular chains are stacked by π-π inter-actions, forming a three-dimensional supra-molecular architecture. In (II), similar C-H⋯O hydrogen bonds as in (I) define inversion dimers, whilst C-H⋯.π inter-actions build a staircase structure along the a axis.
标题化合物C₁₅H₁₂Br₂OS₂（I）和C₂₀H₁₅BrOS（II）是通过在甲醇钾存在下，使3 - 戊酮和二苄基丙酮与5 - 溴噻吩 - 2 - 甲醛进行克莱森 - 施密特缩合反应合成的。尽管预计在这两个反应中都生成1:2的产物，但分别得到了1:2和1:1的产物（I）和（II）。在（I）中，两个甲基彼此反式排列，与它们之间的中心羰基键的夹角分别为29.5（7）°和28.7（7）°，而二苄基丙酮的两个苯环形成的二面角为53.09（18）°。在（I）的晶体中，C—H⋯O氢键沿c轴定义了分子链。通过C—Br⋯π相互作用沿b轴形成了第二种分子链。这两类分子链通过π - π相互作用堆积，形成三维超分子结构。在（II）中，与（I）中类似的C—H⋯O氢键定义了反演二聚体，而C—H⋯π相互作用沿a轴构建了阶梯状结构。
