Powder Structure Analysis of Vapochromic Quinolone Antibacterial Agent Crystals
Powder Structure Analysis of Vapochromic Quinolone Antibacterial Agent Crystals
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气色喹诺酮抗菌剂晶体的粉末结构分析
DOI：
10.1021/acs.cgd.6b00719
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发表时间：
2016
影响因子：
3.8
通讯作者：
H. Uekusa
中科院分区：
文献类型：
--
作者：
Aya Sakon;A. Sekine;H. Uekusa
汽致变色材料，或那些显示可逆的颜色变化引起的蒸汽，预计将作为有价值的传感器的挥发性有机化合物或湿度。喹诺酮类抗菌剂哌哌甲酯酸（PPA）的晶体在乙腈蒸气存在下发生可逆的颜色变化，表现出汽色性。无色三水合物相在暴露于乙腈蒸气时转化为黄色无水相，并在高湿度下返回到三水合物相。从粉末衍射和固态13 C NMR测量的从头算结构测定表明，该分子存在于其两性离子的形式在无色的三水合物相，而它是非两性离子的无水相，因为氢键的重排，由于在晶体状态下的脱水。理论计算表明，PPA的颜色变化是由于分子的电子状态的变化后，采取非两性离子的形式，这使得它的颜色变化。
Vapochromic materials, or those that show a reversible color change induced by vapor, are expected to serve as valuable sensors for volatile organic compounds or humidity. Crystals of pipemidic acid (PPA), a quinolone antibacterial agent, were found to exhibit vapochromism, as they undergo a reversible color change in the presence of acetonitrile vapor. The colorless trihydrate phase transformed into a yellow anhydrous phase upon exposure to acetonitrile vapor and returned to the trihydrate phase under high humidity. Ab initio structure determination from powder diffraction and solid state 13C NMR measurements revealed that the molecule exists in its zwitterionic form in the colorless trihydrate phase, whereas it is non-zwitterionic in the anhydrous phase because of the rearrangement of hydrogen bonds, due to dehydration in the crystal state. Theoretical calculations revealed that the color change in PPA is due to the change in the molecular electronic state upon taking the non-zwitterionic form, which ge...