作者:Susana S. Braga、Paulo Ribeiro-Claro、Martyn Pillinger、Isabel S. Gonçalves、Florbela Pereira、Ana C. Fernandes、Carlos C. Romão、Pedro Brito Correia、José J. C. Teixeira-Dias
DOI:10.1039/b211295g
日期:2003.2.27
Crystalline 1 : 1 inclusion complexes with β-cyclodextrin (β-CD) and the sodium salt of nimesulide (4-nitro-2-phenoxymethanesulfonanilide), and the sodium salt of the derivative 2-phenoxymethanesulfonanilide, have been prepared by co-precipitation from aqueous solution. The presence of true inclusion complexes was supported by elemental analysis, thermogravimetry and powder X-ray diffraction. FTIR and 13C CP MAS NMR spectroscopy confirmed that no chemical modification of the guests occurred upon formation of inclusion complexes. The reaction of the precursors 2-phenoxynitrobenzene and 2-phenoxyaniline with β-CD was also studied and crystalline inclusion complexes with a 2 : 1 (host-to-guest) stoichiometry were isolated. The interaction of the different guest species with β-CD host molecules was studied theoretically by carrying out ab initio calculations. Favourable inclusion geometries were obtained for the four guests mentioned above. On the other hand, it was found that the inclusion of the neutral guests nimesulide and 2-phenoxymethanesulfonanilide was considerably less favourable. This is in agreement with the experimentally observed difficulty in isolating true inclusion complexes containing these guests and β-CD. The calculated lower stability is attributed to the different steric hindrance arising from the different conformational preferences of neutral and anionic forms.
通过从水溶液中共同沉淀,制备了与β-环糊精(β-CD)和尼美舒利(4-硝基-2-苯氧基甲磺酰苯胺)钠盐以及衍生物2-苯氧基甲磺酰苯胺钠盐的1:1晶体包合物。元素分析、热重分析和粉末X射线衍射证实了真正包合物的存在。FTIR和13C CP MAS NMR光谱证实,在形成包合物时,客体没有发生化学变化。还研究了前体2-苯氧基硝基苯和2-苯氧基苯胺与β-CD的反应,并分离出了2:1(主客体)化学计量的晶体包合物。通过从头计算,从理论上研究了不同客体与β-CD主分子之间的相互作用。上述四种客体获得了有利的包合几何结构。另一方面,发现中性客体尼美舒利和2-苯氧基甲磺酰苯胺的包合效果要差得多。这与实验中分离含有这些客体和β-CD的真正包合物所遇到的困难相吻合。计算出的较低稳定性归因于中性形式和阴离子形式不同的构象偏好所产生的不同空间位阻。