Interfacial assembly of an achiral zinc phthalocyanine at the air/water interface: a surface pressure dependent aggregation and supramolecular chirality.
Interfacial assembly of an achiral zinc phthalocyanine at the air/water interface: a surface pressure dependent aggregation and supramolecular chirality.
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DOI：
10.1021/la703703e
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发表时间：
2008-06
期刊：
影响因子：
--
通讯作者：
Yunfeng Qiu;Penglei Chen;Minghua Liu
中科院分区：
文献类型：
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作者：
Yunfeng Qiu;Penglei Chen;Minghua Liu
研究了非手性邻苯二甲酸锌2，3，9，10，16，17，23，24-八(辛氧基)-29H，31H-邻苯二甲酸锌(ZnPc)的界面聚集和超分子手性，观察到了表面压力依赖的行为。研究发现，ZnPc能以朗缪尔膜的形式在水面上扩散，并通过水平提升法转移到固体载体上。该化合物在转移的Langmuir-Blodgett(LB)膜中形成了混合的J-和H-聚集体。对展宽的Q带进行去卷积，得到三个主要的光谱成分，分别对应于H-聚集体、J-聚集体和中等过渡聚集体，它们的相对含量可以通过转移薄膜的表面压力来调节。另一方面，当漂浮膜在一定的表面压力下被压缩时，由这些聚集体组成的转移的LB膜在圆二色谱中表现出Cotton效应，尽管化合物本身是非手性的。大环环通过界面组织以螺旋方式的协同排列可能是导致这种光学活性的原因。提出了一种可能的解释，这是基于聚集体中的ZnPc构建块在螺旋意义上堆积的协同排列。
The aggregation and supramolecular chirality of the interfacial assemblies of an achiral phthalcyanine derivative, zinc 2,3,9,10,16,17,23,24-octakis(octyloxy)-29 H,31 H-phthaloxyanine (ZnPc), were investigated, and a surface pressure dependent behavior was observed. It was found that ZnPc could be spread as a Langmuir film on water surface and transferred onto solid substrates by the horizontal lifting method. The compound formed mixed J- and H-aggregates in the transferred Langmuir-Blodgett (LB) films. Deconvolution of the broaden Q-band revealed three main components of the spectra, which corresponded to H- and J-aggregates and medium transition aggregates, whose relative contents could be modulated by the surface pressure at which the films were transferred. On the other hand, the transferred LB films composed of these aggregates showed Cotton effects in circular dichroism spectra when the floating film was compressed over a certain surface pressure although the compound itself was achiral. The cooperative arrangement of the macrocylic ring in a helical manner through the interfacial organization was suggested to be responsible for such optical activity in the LB films. A possible explanation based on the cooperative arrangement of the ZnPc building blocks in a helical sense stacking in the aggregates was proposed.