Color Changes Caused by Conformational Polymorphism: Optical-Crystallography, Single-Crystal Spectroscopy, and Computational Chemistry
Color Changes Caused by Conformational Polymorphism: Optical-Crystallography, Single-Crystal Spectroscopy, and Computational Chemistry
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构象多态性引起的颜色变化：光学晶体学、单晶光谱学和计算化学
DOI：
10.1021/jp013019c
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发表时间：
2002
影响因子：
2.9
通讯作者：
Lian Yu
中科院分区：
文献类型：
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作者：
Lian Yu
5-甲基-2-[（2-硝基苯基）氨基]-3-噻吩甲腈（1）结晶为红色、橙子和黄色的7种构象多晶型物。相似的热力学稳定性的多晶型物，使解决方案的六个晶体结构，一个数字无法匹配的当前条目在剑桥结构数据库，使1非常适合结构-性能的研究。利用光学晶体学、偏振单晶吸收光谱和计算方法研究了1的不同晶体颜色。不同的晶体颜色（“颜色多态性”）可以很好地解释为多晶型物之间的构象差异，这导致邻硝基苯胺发色团和噻吩基团之间不同程度的π共轭。晶体多晶型物中不同构象的隔离允许通过观察到的光谱性质来评估电子结构和跃迁的计算模型。新近成熟的含时密度泛函理论给出了最好的计算结果。
5-Methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (1) crystallizes as seven conformational polymorphs of red, orange, and yellow colors. Comparable thermodynamic stability of the polymorphs enables the solution of six crystal structures, a number unmatched by current entries in the Cambridge Structural Database, making 1 well suited for structure−property studies. The different crystal colors of 1 have been studied using optical crystallography, polarized single-crystal absorption spectroscopy and computational methods. Different crystal colors (“color polymorphism”) are well explained by the conformational differences between polymorphs, which cause varying degrees of π-conjugation between the o-nitroaniline chromophore and the thiophene group. The isolation of different conformers in crystal polymorphs permits an evaluation of computational models of electronic structures and transitions through observed spectral properties. The newly matured Time Dependent Density Functional Theory gave the bes...