Kia Reza, Fun Hoong-Kun, Kargar Hadi
Acta Crystallogr Sect E Struct Rep Online. 2009 Apr 18;65(Pt 5):o1071-2. doi: 10.1107/S1600536809013804.
The asymmetric unit of the title compound, C(19)H(22)N(2)O(2)·2H(2)O, comprises a zwitterionic form of the Schiff base compound and two water mol-ecules of crystallization. Inter-molecular N-H⋯O, C-H⋯O and O-H⋯N hydrogen bonds involving one of the water mol-ecules in the asymmetric unit generate seven- and eight-membered rings, with R(2) (1)(7) and R(2) (2)(8) ring motifs, respectively. The dihedral angle beween the two aromatic rings is 86.5 (2)°. The imino and iminium groups are coplanar with the benzene rings to which they are attached, making dihedral angles (N-C-C-C) of -179.3 (5) and -179.2 (4)°, respectively. Validation software indicates the higher symmetry space group Pnma for this structure. However, this process ignores H atoms and the zwitterionic configuration of the main mol-ecule breaks the higher symmetry. Solution in Pna2(1) provides a chemically sensible zwitterionic compound with improved residuals. In the crystal structure, mol-ecules are linked together through inter-molecular O-H⋯O, O-H⋯N, N-H⋯O and C-H⋯O inter-actions, forming a three-dimensional network. The crystal structure is further stabilized by inter-molecular C-H⋯π inter-actions.
标题化合物C(19)H(22)N(2)O(2)·2H(2)O的不对称单元包含席夫碱化合物的两性离子形式和两个结晶水分子。涉及不对称单元中一个水分子的分子间N-H⋯O、C-H⋯O和O-H⋯N氢键分别形成具有R(2) (1)(7)和R(2) (2)(8)环模式的七元环和八元环。两个芳香环之间的二面角为86.5 (2)°。亚氨基和亚胺鎓基团与它们所连接的苯环共面，二面角（N-C-C-C）分别为-179.3 (5)°和-179.2 (4)°。验证软件表明该结构具有更高对称性的空间群Pnma。然而，这个过程忽略了氢原子，并且主分子的两性离子构型破坏了更高的对称性。在Pna2(1)中求解得到一个化学上合理的两性离子化合物，其残余值有所改善。在晶体结构中，分子通过分子间的O-H⋯O、O-H⋯N、N-H⋯O和C-H⋯O相互作用连接在一起，形成三维网络。晶体结构通过分子间的C-H⋯π相互作用进一步稳定。
