Stereochemistry‐Controlled Supramolecular Architectures of New Tetrahydroxy‐Functionalised Amphiphilic Carbocyanine Dyes
Stereochemistry‐Controlled Supramolecular Architectures of New Tetrahydroxy‐Functionalised Amphiphilic Carbocyanine Dyes
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DOI：
10.1002/chem.201905745
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发表时间：
2020-02
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通讯作者：
B. Schade;A. Singh;Virginia Wycisk;J. L. Cuéllar-Camacho;H. Berlepsch;R. Haag;C. Böttcher
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文献类型：
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作者：
B. Schade;A. Singh;Virginia Wycisk;J. L. Cuéllar-Camacho;H. Berlepsch;R. Haag;C. Böttcher
摘要 报道了具有氨基丙二醇头基的新型两亲性 5,5',6,6'-四氯苯甲酰亚胺碳花青 (TBC) 染料衍生物的合成，其仅在立体化学上有所不同（手性对映体、内消旋形式和构象异构体）。对于非手性内消旋形式，建立了一条新的不对称花青染料合成路线。所有化合物在水中形成J聚集体，其光学性质通过光谱方法表征。通过冷冻透射电子显微镜、冷冻电子断层扫描和原子力显微镜研究了聚集体的超分子结构，分别揭示了手性对映异构体的扩展片状聚集体和介观异构体的纳米管，而构象异构体主要形成针状晶体。实验表明，化合物的聚集行为可以仅通过头基立体化学来控制，在对映体的情况下，可以通过羟基官能团形成延长的氢键链。然而，在非手性内消旋形式的情况下，这种链在空间上被排除。
Abstract The syntheses of novel amphiphilic 5,5′,6,6′‐tetrachlorobenzimidacarbocyanine (TBC) dye derivatives with aminopropanediol head groups, which only differ in stereochemistry (chiral enantiomers, meso form and conformer), are reported. For the achiral meso form, a new synthetic route towards asymmetric cyanine dyes was established. All compounds form J aggregates in water, the optical properties of which were characterised by means of spectroscopic methods. The supramolecular structure of the aggregates is investigated by means of cryo‐transmission electron microscopy, cryo‐electron tomography and AFM, revealing extended sheet‐like aggregates for chiral enantiomers and nanotubes for the mesomer, respectively, whereas the conformer forms predominately needle‐like crystals. The experiments demonstrate that the aggregation behaviour of compounds can be controlled solely by head group stereochemistry, which in the case of enantiomers enables the formation of extended hydrogen‐bond chains by the hydroxyl functionalities. In case of the achiral meso form, however, such chains turned out to be sterically excluded.