Ishida Hiroyuki
Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
Acta Crystallogr E Crystallogr Commun. 2021 Oct 26;77(Pt 11):1144-1152. doi: 10.1107/S2056989021010896. eCollection 2021 Nov 1.
The structures of the six hydrogen-bonded 1:1 compounds of 4-methyl-quinoline (CHN) with chloro- and nitro-substituted benzoic acids (CHClNO), namely, 4-methyl-quinolinium 2-chloro-4-nitro-benzoate, CHN·CHClNO , (I), 4-methyl-quinoline-2-chloro-5-nitro-benzoic acid (1/1), CHN·CHClNO, (II), 4-methyl-quinolinium 2-chloro-6-nitro-benzoate, CHN·CHClNO , (III), 4-methyl-quinolinium 3-chloro-2-nitro-benzoate, CHN·CHClNO , (IV), 4-methyl-quinolinium 4-chloro-2-nitro-benzoate, CHN·CHClNO , (V), and 4-methyl-quinolinium 5-chloro-2-nitro-benzoate, CHN·CHClNO , have been determined at 185-190 K. In each compound, the acid and base mol-ecules are linked by a short hydrogen bond between a carb-oxy (or carboxyl-ate) O atom and an N atom of the base. The O⋯N distances are 2.5652 (14), 2.556 (3), 2.5485 (13), 2.5364 (13), 2.5568 (13) and 2.5252 (11) Å, respectively, for compounds (I)-(VI). In the hydrogen-bonded acid-base units of (III) and (IV), the H atoms are each disordered over two positions with O site:N site occupancies of 0.37 (3):0.63 (3) and 0.46 (3):0.54 (4), respectively, for (III) and (IV). The H atoms in the hydrogen-bonded units of (I), (V) and (VI) are located at the N-atom site, while the H atom in (II) is located at the O-atom site. In all the crystals of (I)-(VI), π-π stacking inter-actions between the quinoline ring systems and C-H⋯O hydrogen bonds are observed. Similar layer structures are constructed in (IV)-(VI) through these inter-actions together with π-π inter-actions between the benzene rings of the adjacent acid mol-ecules. A short Cl⋯Cl contact and an N-O⋯π inter-action are present in (I), while a C-H⋯Cl hydrogen bond and a π-π inter-action between the benzene ring of the acid mol-ecule and the quinoline ring system in (II), and a C-H⋯π inter-action in (III) are observed. Hirshfeld surfaces for the title compounds mapped over and shape index were generated to visualize the weak inter-molecular inter-actions.
已在185 - 190 K下测定了4 - 甲基喹啉（CHN）与氯代和硝基取代苯甲酸（CHClNO）形成的六种氢键1:1化合物的结构，即4 - 甲基喹啉鎓2 - 氯 - 4 - 硝基苯甲酸盐，CHN·CHClNO ，（I）；4 - 甲基喹啉 - 2 - 氯 - 5 - 硝基苯甲酸（1/1），CHN·CHClNO，（II）；4 - 甲基喹啉鎓2 - 氯 - 6 - 硝基苯甲酸盐，CHN·CHClNO ，（III）；4 - 甲基喹啉鎓3 - 氯 - 2 - 硝基苯甲酸盐，CHN·CHClNO ，（IV）；4 - 甲基喹啉鎓4 - 氯 - 2 - 硝基苯甲酸盐，CHN·CHClNO ，（V）；以及4 - 甲基喹啉鎓5 - 氯 - 2 - 硝基苯甲酸盐，CHN·CHClNO ，（VI）。在每种化合物中，酸和碱分子通过羰基（或羧酸盐）O原子与碱的N原子之间的短氢键相连。对于化合物（I） - （VI），O⋯N距离分别为2.5652 (14)、2.556 (3)、2.5485 (13)、2.5364 (13)、2.5568 (13)和2.5252 (11) Å。在（III）和（IV）的氢键酸碱单元中，H原子在两个位置上无序分布，对于（III）和（IV），O位点:N位点占有率分别为0.37 (3):0.63 (3)和0.46 (3):0.54 (4)。（I）、（V）和（VI）的氢键单元中的H原子位于N原子位点，而（II）中的H原子位于O原子位点。在（I） - （VI）的所有晶体中，观察到喹啉环系统之间的π - π堆积相互作用以及C - H⋯O氢键。通过这些相互作用以及相邻酸分子苯环之间的π - π相互作用，在（IV） - （VI）中构建了类似的层状结构。（I）中存在短的Cl⋯Cl接触和N - O⋯π相互作用，（II）中观察到酸分子苯环与喹啉环系统之间的C - H⋯Cl氢键和π - π相互作用，（III）中观察到C - H⋯π相互作用。生成了标题化合物的Hirshfeld表面映射在 和形状指数上，以可视化弱分子间相互作用。
