Institute of Materials and Chemical Engineering, Sichuan University of Science and Engineering, Zigong 643000, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Feb;75(2):753-9. doi: 10.1016/j.saa.2009.11.050. Epub 2009 Dec 1.
A novel Schiff base of 4,5-diazafluorene-9-p-nitrophenylhydrazone (DAFND) has been synthesized and characterized. The crystal structures of DAFND and its analogue 4,5-diazafluorene-9-phenylhydrazone (DAFPD) were determined by single crystal X-ray diffraction method. X-ray analyses reveal that DAFPD comprise of a nonplanar molecule and all atoms of DAFND are essentially coplanar. The color of DAFND changes from brown to blue when heated, so called thermochromism and the spectroscopic properties of the two compounds are investigated by electronic absorption spectra, showing DAFND possess solvatochromism, while DAFPD does not have thermochromic and solvatochromic properties. The lambda(max) of DAFND within various pure solvents are different ranging from 370 nm in toluene to 614 nm in pyridine. The imaginable mechanisms of thermochromism and solvatochromism are proposed.
一种新型的 4,5-二氮杂芴-9-对硝基苯腙（DAFND）席夫碱已被合成并进行了表征。通过单晶 X 射线衍射法确定了 DAFND 和其类似物 4,5-二氮杂芴-9-苯腙（DAFPD）的晶体结构。X 射线分析表明，DAFPD 由一个非平面分子组成，而 DAFND 的所有原子基本上都是共面的。DAFND 在加热时颜色从棕色变为蓝色，即热致变色，通过电子吸收光谱研究了这两种化合物的光谱性质，结果表明 DAFND 具有溶剂变色性，而 DAFPD 没有热致变色和溶剂变色性质。DAFND 在各种纯溶剂中的 lambda(max)不同，范围从甲苯中的 370nm 到吡啶中的 614nm。提出了热致变色和溶剂变色的可能机制。
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