Ambidextrous optically active copper(II) phthalocyanine supramolecules induced by peripheral group homochirality
Ambidextrous optically active copper(II) phthalocyanine supramolecules induced by peripheral group homochirality
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DOI：
10.1039/c0nj00374c
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发表时间：
2010-10
影响因子：
3.3
通讯作者：
Wei Zhang;Akira Ishimaru;H. Onouchi;R. Rai;A. Saxena;Akihiro Ohira;M. Ishikawa;M. Naito;M. Fujiki
中科院分区：
文献类型：
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作者：
Wei Zhang;Akira Ishimaru;H. Onouchi;R. Rai;A. Saxena;Akihiro Ohira;M. Ishikawa;M. Naito;M. Fujiki
研究了在酞菁铜（Pc）分子外围分别带有4个对映体纯的（S）-和（R）-1-（对甲苯基）乙氨基羰基的盘状分子CuPc-（S）和CuPc-（R）的自组装特性.为了比较，使用带有外消旋1-（对甲苯基）乙氨基羰基的类似CuPc，CuPc-（RS）。从圆二色性和可见/红外光谱研究与广角X射线衍射数据，CuPc-（S）和CuPc-（R）被证明产生光学活性的π−π堆叠组件中形成的极性较低的溶剂。CuPc-（RS）产生类似的组件，在极性较低的溶剂中的光学活性的损失。Pcπ/Pcπ堆积的多重相互作用、四重氢键、外围基团的同手性立构中心、庞大的芳烷基实体和铜（II）的弱配位性质被认为是形成光学活性CuPc组装体的原因。溶剂效应是明显的：极性较低的氯仿和四氢呋喃有助于产生光学活性的CuPc组装，而高极性的N，N-二甲基甲酰胺由于Pc-Pc分子间氢键相互作用的损失而产生单体Pc物种。CuPc的自组装能力与先前报道的携带相同手性外围的NiPc类似物相似。原子力显微镜研究表明，将CuPc-（S）、CuPc-（R）和CuPc-（RS）的氯仿稀溶液浇铸到云母表面，观察到蠕虫状的超分子聚合物，而NiPc-（R）类似物提供针状的超分子聚合物。
Self-assembling features of the disk-shaped copper(II) phthalocyanine (Pc) molecules carrying four enantiopure (S)- and (R)-1-(p-tolyl)ethylaminocarbonyl groups at their peripheral positions, CuPc-(S) and CuPc-(R), were studied. For comparison, an analogous CuPc carrying racemic 1-(p-tolyl)ethylaminocarbonyl groups, CuPc-(RS), was used. From circular dichroism and visible/infrared spectroscopic studies with wide-angle-X-ray diffraction data, CuPc-(S) and CuPc-(R) were shown to generate optically active π−π stacked assemblies formed in less-polar solvents. CuPc-(RS) produced similar assemblies with a loss of optical activity in the less-polar solvents. Plural interactions of Pcπ/Pcπ stacking, quadruple hydrogen bonding, homochiral stereocenters at the peripheral groups, bulky aralkyl entities and weak coordinating nature of copper(II) of the CuPcs were thought to be responsible for the formation of the optically active CuPc assemblies. The solvent effect was evident: less polar chloroform and tetrahydrofuran helped to generate the optically active CuPc assembly while highly polar N,N-dimethylformamide gave a monomeric Pc species due to the loss of Pc–Pc intermolecular hydrogen-bonding interaction. The self-assembling ability of the CuPcs was similar to NiPc analogues carrying the same chiral peripherals reported previously. Atomic force microscope study revealed that by casting dilute chloroform solutions of CuPc-(S), CuPc-(R) and CuPc-(RS) onto mica surface, worm-like supramolecular polymers were observed while the NiPc-(R) analogue provided needle-like supramolecular polymers.