Molecular machines were attractive for scientists due to their excellent dynamical properties and potential applications. Inspired by the feature of molecular machine, we designed an ideal unscrewing process of double-chain sexipyridine complex with four conformations and explored the variation of stability and optical properties. As a result, we found the double helices where the fragments bound by only weak π-π interaction had poor stability. Thus the conformation with stronger π-π interaction was more stable than others. But this could be changed by adding alkali metals, and different alkali metal atoms such as Li and Na could control the stability order because of their different atomic radii. For Li-doped molecules, Li-1 with tightly coiled strands was the most stable conformation. While for Na-doped molecules, Na-4 with unscrewed fragments was the most stable one. This mainly resulted from the intra-molecular interaction potential energy especially the interaction between metal and ligand. At the same time, the charge distribution showed corresponding variation. In the aspect of optical properties, the unscrewing process was followed by the variation of absorption intensity at about 500 nm in the UV–Vis absorption spectra because of the conformation change. Meanwhile, the first-order static hyperpolarizability (β_tot) showed zigzag variation due to the change of frontier molecular orbital energy gap in the unscrewing process.

分子机器因其出色的动力学特性和潜在应用而吸引了科学家。受分子机器特性的启发，我们设计了一种理想的具有四个构象的双链六氟吡啶配合物旋松方法，并探索了稳定性和光学性质的变化。结果，我们发现了双螺旋，其中仅由弱π-π相互作用束缚的片段具有较差的稳定性。因此，具有更强π-π相互作用的构象比其他构象更稳定。但这可以通过添加碱金属来改变，并且不同的碱金属原子（例如Li和Na）可以控制稳定性顺序，因为它们的原子半径不同。对于掺杂锂的分子，Li-1紧密缠绕的链是最稳定的构象。对于掺Na的分子，带有未旋片段的Na-4是最稳定的分子。这主要是由于分子内相互作用势能，特别是金属与配体之间的相互作用所致。同时，电荷分布显示出相应的变化。在光学性能方面，由于构象变化，在拧松过程之后，在UV-Vis吸收光谱中约500 nm处的吸收强度发生变化。同时，第一阶静态超极化率（β _TOT）显示锯齿状变化，由于前沿分子轨道的能隙在拧开过程的变化。