作者:Takahiro Seki、Takashi Fukuchi、Kunihiro Ichimura
DOI:10.1246/bcsj.71.2807
日期:1998.12
An azobenzene (Az) containing amphiphile having a urea head group [N-(10-4-[(4-hexylphenyl)azo]phenoxy})decylurea (6Az10-Urea)] was synthesized for the first time, and the spreading behavior, morphology, absorption spectral features, and photoreactivity of this amphiphile at the air–water interface was examined. The features of this monolayer were argued in comparison with those of a carboxylic acid derivative of the homologous structure. Polymer-like stable stable monolayers were formed form 6Az10-Urea both in the trans and cis forms of the Az unit, possibly indicating the formation of intermolecular bifurcated NH···O=C hydrogen bonds of urea heads. Unlike monolayers of simple long alkylureas, the present monolayer did not show a thermal phase transition within the temperature region examined (10—35 °C). In the trans-6Az10-Urea monolayer, the Az unit formed tilted aggregates. In this aggregation state, the trans-to-cis photoisomerization in the 6Az10-Urea monolayer was completely hindered despite the fact that the monolayer was more expanded than that of a corresponding carboxylic acid derivative in which the photoisomerization proceeded.
首次合成了一种含有脲头基的偶氮苯(Az)双亲化合物[N-(10-4-[(4-己基苯基)偶氮]苯氧基})癸基脲(6Az10-Urea)],并研究了这种双亲化合物在空气-水界面上的铺展行为、形态、吸收光谱特征和光活性。通过与同源结构的羧酸衍生物进行比较,论证了这种单分子层的特征。在 Az 单元的反式和顺式中,6Az10-脲都形成了类似聚合物的稳定单层,这可能表明脲头形成了分子间分叉的 NH-O=C 氢键。与简单的长烷基脲单层不同,本单层在考察温度区域(10-35 °C)内没有出现热相变。在反式-6Az10-脲单层中,Az 单元形成了倾斜的聚集体。在这种聚集状态下,6Az10-脲单层中的反式-顺式光异构化完全受阻,尽管该单层比相应的羧酸衍生物的单层更宽大,而在后者中光异构化继续进行。