The structural characterisation of the molecule 1,4-bis[2-cyano-2-(o-pyridyl)ethenyl] benzene obtained through Knoevenagel condensation is reported. The single crystals, as light brown rods, were cultured from a chloroform solution using a slow evaporation method at ambient temperature. The compound crystallised in the monoclinic system belonging to the C2/c space group with a = 26.4556(9) Å, b = 3.73562(10) Å, c = 18.4230(6) Å, β = 109.841(4)° and the asymmetric unit comprising Z = 4. The structure is ordered and the molecules of the title compound exhibited a lattice with water molecules located at sites of inversion and two-fold axial symmetries. Thus, only halves of the molecules are symmetrically independent. The lattice is reported and contrasted with X-ray single-crystal diffraction and theoretical calculations of 1,4-bis(1-cyano-2-phenylethenyl)benzene. By using density functional theory (DFT) and second order Moller-Plesset (MP2) theoretical calculations, the ground state geometry in the whole molecule at the B3LYP/6-31+G(d,p), and MP2/6-31+G(d,p) theory levels, respectively, were optimised. The DFT calculations showed a quasi-planar structure of the molecule, whereas the wave function-based MP2 method afforded a non-planar optimised structure with significant torsion angles between the pyridine and phenyl rings.

中文翻译：

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1,4-双[2-氰基-2-（邻吡啶基）乙烯基]苯的X射线分子结构及理论研究

报道了通过Knoevenagel缩合获得的分子1,4-双[2-氰基-2-（邻-吡啶基）乙烯基]苯的结构表征。在室温下使用缓慢蒸发法从氯仿溶液中培养出浅褐色棒状的单晶。在单斜晶系中结晶的化合物属于C 2 / c空间群，其中a = 26.4556（9）Å，b = 3.73562（10）Å，c = 18.4230（6）Å，β = 109.841（4）°，且包含Z的不对称单元＝ 4。结构是有序的，标题化合物的分子表现出晶格，其中水分子位于反型位点并且具有两个轴向对称性。因此，只有一半的分子是对称独立的。报告了晶格，并与X射线单晶衍射和1,4-双（1-氰基-2-苯基乙烯基）苯的理论计算作了对比。通过使用密度泛函理论（DFT）和二阶Moller-Plesset（MP2）理论计算，得出整个分子在B3LYP / 6-31 + G（d，p）和MP2 / 6-31 +处的基态几何分别优化了G（d，p）理论水平。DFT计算显示了分子的准平面结构，而基于波函数的MP2方法提供了在吡啶和苯环之间具有明显扭转角的非平面优化结构。