Gowda Ashwathanarayana, Acharjee Gourab, Pathak Suraj Kumar, Rohaley Grace A R, Shah Asmita, Lemieux Robert P, Prévôt Marianne E, Hegmann Torsten
Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
Mater Horiz. 2024 Nov 11;11(22):5550-5563. doi: 10.1039/d4mh01243g.
Self-assembled lamellar nano- and microfilaments formed by select types of bent-core molecules are prime examples of the interplay between molecular conformation and morphological chirality. Here, we demonstrate how the strategic placement of chiral centers at C-1 and/or C-3 in the terminal alkyloxy side chains, largely based on calculations of molecular conformation, leads to the predictable formation of increasingly complex nano- and microfilament morphologies. Adding to the previously described diversity of twisted and writhed filament types, we here demonstrate and explain the formation and coexistence of flat nanoribbons, nanocylinders, or nano- as well as microfilaments where the morphology spontaneously changes along the filament long axis. For some these more exotic types of filament morphology, helical multilayer filaments suddenly unwind to form flat nanoribbons that also twist again under preservation (not perversion) of the helical twist sense. Moreover, the morphologies formed by this series of molecules now allows us to demonstrate the complete transformation from flat multilayer ribbons over microfilaments and helical-wrapped nanocylinders to helical nanofilaments depending on the number and position of chiral centers in the aliphatic side chains.
由特定类型的弯曲核分子形成的自组装层状纳米和微丝是分子构象与形态手性之间相互作用的典型例子。在此，我们展示了如何主要基于分子构象计算，在末端烷氧基侧链的C-1和/或C-3处有策略地引入手性中心，从而可预测地形成越来越复杂的纳米和微丝形态。除了先前描述的扭曲和缠绕丝状类型的多样性之外，我们在此展示并解释了扁平纳米带、纳米圆柱体或纳米以及微丝的形成和共存，其中形态会沿丝的长轴自发变化。对于某些这些更奇特的丝状形态类型，螺旋多层丝会突然展开形成扁平纳米带，这些纳米带在保持（而非扭曲）螺旋扭转方向的情况下也会再次扭转。此外，这一系列分子形成的形态现在使我们能够展示从扁平多层带到微丝、螺旋缠绕纳米圆柱体再到螺旋纳米丝的完整转变，这取决于脂肪族侧链中手性中心的数量和位置。
