Beijing National Laboratory for Molecular Science, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190, China.
Phys Chem Chem Phys. 2011 Oct 14;13(38):17205-9. doi: 10.1039/c1cp21767d. Epub 2011 Aug 30.
The self-assembly and supramolecular chirality of a dianionic tetrakis(4-sulfonatophenyl) porphyrin (TPPS) in the presence of ionic liquids, 1-alkyl-3-methylimidazolium tetrafluoroborate (alkyl = C(2), C(4) or C(6), abbreviated as C(2)mimBF(4), C(4)mimBF(4) and C(6)mimBF(4), respectively), have been investigated. It has been confirmed that mimBF(4) ionic liquids significantly promoted the J-aggregation of TPPS and the alkyl chain length in the imidazolium cation was closely related to the TPPS aggregation, the inducing ability of which decreased in the order of C(2), C(4) or C(6) in side chain. Interestingly, the formed TPPS assemblies with the ionic liquids showed supramolecular chirality although both TPPS and ionic liquids are achiral. It was found that the supramolecular chirality of the TPPS/IL system always appeared after the formation of the J aggregate. The dynamic process of the emergence of the handedness in the initial achiral system was monitored by the time-dependent CD spectra. A mechanism for the transformation of the conventional J-aggregate to the chiral J-aggregate was proposed. The work will lead to a deeper understanding of the chiral symmetry breaking in the supramolecular system.
在离子液体 1-烷基-3-甲基咪唑四氟硼酸盐（烷基= C(2)、C(4)或 C(6)，分别缩写为 C(2)mimBF(4)、C(4)mimBF(4)和 C(6)mimBF(4)）的存在下，研究了二阴离子四（4-磺基苯基）卟啉（TPPS）的自组装和超分子手性。已经证实，mimBF(4)离子液体显著促进了 TPPS 的 J-聚集，并且咪唑阳离子中的烷基链长度与 TPPS 聚集密切相关，其诱导能力按侧链中的 C(2)、C(4)或 C(6)顺序降低。有趣的是，尽管 TPPS 和离子液体都是手性的，但形成的具有离子液体的 TPPS 组装体表现出超分子手性。发现 TPPS/IL 体系的超分子手性总是在形成 J 聚集体之后出现。通过时间分辨 CD 光谱监测初始非手性体系中手性出现的动态过程。提出了一种将常规 J-聚集体转化为手性 J-聚集体的机制。这项工作将加深对手征对称破缺在超分子体系中的理解。
