C 3的三个家族系列的手性扩增特征的比较研究此处报道了对称的三甲酰胺,1,3,5-三苯基苯三甲酰胺(TPBA),苯三甲酰胺(BTA)和低聚(亚苯基乙炔基)三甲酰胺(OPE-TA)。正如以前对BTA和OPE-TA所观察到的那样,对于装饰有一个,两个或三个带有立体异构中心的手性侧链的TPBA,也获得了类似的二向色响应,从而证实了点手性向超分子螺旋聚集体的有效转移。与BTA和OPE-TA不同,大多数规则实验中TPBA的手性扩增能力显示其对每个单体单元的手性中心数量的依赖性可以忽略不计,并且在三羧酰胺系列中最大。详细的实验和理论研究表明,螺旋堆叠中TPBA单元之间的旋转角度是BTA和OPE-TA所观察到的中间角度。该特征强烈地调节了堆叠中的邻近分子与最终手性扩增结果之间的空间相互作用。此外,理论计算表明,非手性侧链有利于螺旋聚集体的叉指化,从而有助于形成束超结构。
Supramolecular Polymerization of [5]Helicenes. Consequences of Self-Assembly on Configurational Stability
作者:Jorge S. Valera、Rafael Gómez、Luis Sánchez
DOI:10.1021/acs.orglett.8b00565
日期:2018.4.6
The supramolecular polymerization of [5]helicenes 1 and 2 is investigated. The self-assembly of these helicenes proceeds by the operation of H-bonding interactions with a negligible participation of π-stacking. The enantiopurity of the sample has a dramatic effect on the supramolecular polymerization mechanism since it reverts the isodesmic mechanism for the racemic mixture to a cooperative one for
The tunable luminescent features along with the electrical conductivity (∼2 × 10−4 S m−1) exhibited by the gel fibers formed through supramolecular polymerisation of the N-annulated perylenedicarboxamide based π-gelator 1 are reported.
Influence of Axial and Point Chirality in the Chiral Self-Assembly of Twin <i>N</i>-Annulated Perylenecarboxamides
作者:Julia Buendı́a、Elisa E. Greciano、Luis Sánchez
DOI:10.1021/acs.joc.5b02309
日期:2015.12.18
The synthesis of three bis(N-annulated perylenecarboxamides) endowed with achiral or chiral side chains is reported. The restricted rotation of the perylene moieties yields atropisomers that can be separated by chiral HPLC. The CD spectra of the six stereoisomers Show a dichroic pattern in a good solvent that changes drastically upon adding a poor solvent that favors the aggregation. The cooperative character of the supramolecular polymerization mechanism of 1-3 ha 8 been determined by denaturation experiments, which reveal that the formation of homochiral aggregates is favored over the formation of heterochiral aggregates. A complete set of amplification of chirality experiments have been carried out, revealing the preponderance of axial chirality over point chirality. The results presented herein shed relevant light On the structural conditions exhibited by molecular units endowed with different elements of asymmetry to generate chiral supramolecular structures and the supremacy of axial chirality over point chirality in the origin of homochirality.