Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Langmuir. 2022 May 24;38(20):6481-6490. doi: 10.1021/acs.langmuir.2c00796. Epub 2022 May 12.
An air-water interface enables molecular assemblies and conformations to be controlled according to their intrinsic interactions and anisotropic stimuli. The chirality and conformation of binaphthyl derivatives have been controlled by tuning molecular aggregated states in solution. In this study, we have tuned molecular aggregated states of monobinaphthyldurene (MBD) by applying different mechanical stimuli to control the conformation at the air-water interface. Density functional theory calculations indicate that MBD exists essentially in two conformations, namely, 1-MBD (most stable) and 2-MBD (less stable). MBD was mechanically dissolved in appropriate lipid matrices using the Langmuir-Blodgett (LB) method, while pure MBD was self-assembled at the dynamic air-water interface in the absence of or by applying vortex motions (vortex LB method). In MBD mixed monolayer, surface pressure-molecular area measurements and atomic force microscopy observations suggest that separate lipids and MBD phases transform to mixed phases induced by the dissolution of MBD into the lipid matrices during mechanical compression at the air-water interface. Circular dichroism measurements indicate that molecular conformation changes from 1-MBD to 2-MBD in passing from a separated phase to a mixed MBD/lipid phase. In addition, the molecular aggregated states and conformations of MBD depend on the spreading volume and vortex flow rate when applying the vortex LB method. Molecular conformations and aggregated states of MBD could be controlled continuously by applying a mechanical stimulus at the air-water interface.
气-液界面能够根据分子的固有相互作用和各向异性刺激来控制分子组装体和构象。联萘衍生物的手性和构象可以通过调节溶液中分子聚集态来控制。在这项研究中，我们通过施加不同的机械刺激来调节单联萘二芴（MBD）的分子聚集态，以控制在气-液界面的构象。密度泛函理论计算表明，MBD 基本上存在两种构象，即 1-MBD（最稳定）和 2-MBD（不太稳定）。MBD 采用 Langmuir-Blodgett（LB）方法用合适的脂质基质机械溶解，而纯 MBD 在没有或施加涡旋运动（涡旋 LB 方法）的情况下在动态气-液界面自组装。在 MBD 混合单层中，表面压力-分子面积测量和原子力显微镜观察表明，在气-液界面的机械压缩过程中，MBD 溶解到脂质基质中会导致分离的脂质相和 MBD 相转变为混合相。圆二色性测量表明，分子构象从分离相转变为混合 MBD/脂质相时从 1-MBD 转变为 2-MBD。此外，当采用涡旋 LB 方法时，MBD 的分子聚集态和构象取决于铺展体积和涡旋流速。通过在气-液界面施加机械刺激，可以连续控制 MBD 的分子构象和聚集态。
