Abstract The Schiff base 3-{( E )-[(2-hydroxyphenyl)imino]methyl}benzene-1,2-diol was synthesized by the condensation of 2,3-dihydroxybenzaldehyde and 2-aminophenol in water at room temperature. The crystal was grown using two solvents (dry methanol and 60% methanol). The compound was characterized using elemental microanalysis, IR, NMR, UV spectroscopies and single-crystal X-ray diffraction crystallography. The X-ray structure reveals that the Schiff base crystallizes as a methanol solvate in dry methanol with triclinic crystal system, space group P-1 and Z = 2 in the unit cell and as a non-methanol solvate in 60% methanol with triclinic crystal system, space group P-1 and Z = 4 in the unit cell. The compound showed absorption bands at 272, 389, 473 and 602 nm in DMSO. These bands were assigned as π → π ∗ , n → π ∗ and n-σ ∗ transitions. The 473 and 602 nm bands in DMSO reveal that the compound exists in tautomeric forms. The presence of N-H, C-O and C N stretching vibrations in the IR spectrum indicates that the compound is zwitterionic in the solid state. This study was supplemented using density functional theory method.

中文翻译：

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3-{( E )-[(2-羟基苯基)亚氨基]甲基}苯-1,2-二醇的合成、表征和计算研究及其两性离子形式的分子结构

摘要 以2,3-二羟基苯甲醛和2-氨基苯酚在室温下在水中缩合反应合成了席夫碱3-{(E)-[(2-羟基苯基)亚氨基]甲基}苯-1,2-二醇。使用两种溶剂（无水甲醇和 60% 甲醇）生长晶体。该化合物使用元素微量分析、红外、核磁共振、紫外光谱和单晶 X 射线衍射晶体学进行表征。X 射线结构显示，席夫碱在具有三斜晶系、空间群 P-1 和 Z = 2 的无水甲醇中以甲醇溶剂化物形式结晶，晶胞中的空间群为 P-1 和 Z = 2，在 60% 甲醇中作为非甲醇溶剂化物与三斜晶系结晶系统，空间群 P-1 和 Z = 4 在晶胞中。该化合物在 DMSO 中在 272、389、473 和 602 nm 处显示出吸收带。这些带被指定为 π → π ∗ 、n → π ∗ 和 n-σ ∗ 跃迁。DMSO 中的 473 和 602 nm 波段表明该化合物以互变异构形式存在。IR 光谱中 NH、CO 和 CN 伸缩振动的存在表明该化合物在固态下是两性离子的。本研究使用密度泛函理论方法进行补充。