Ni Bing, Vivod Dustin, Avaro Jonathan, Qi Haoyuan, Zahn Dirk, Wang Xun, Cölfen Helmut
Physical Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Chair for Theoretical Chemistry/Computer Chemistry Centre (CCC) Nägelsbachstrasse 25, 91058, Erlangen, Germany.
Nat Commun. 2024 Mar 6;15(1):2042. doi: 10.1038/s41467-024-45935-3.
Responsive chiral systems have attracted considerable attention, given their potential for diverse applications in biology, optoelectronics, photonics, and related fields. Here we show the reversible chirality inversion of an AuAg-cysteine (AuAg-cys) coordination polymer (CP) by pH changes. The polymer can be obtained by mixing HAuCl and AgNO with L-cysteine (or D-cysteine) in appropriate proportions in HO (or other surfactant solutions). Circular dichroism (CD) spectrum is used to record the strong optical activity of the AuAg-L-cys enantiomer (denoted as L0.06), which can be switched to that of the corresponding D0.06 enantiomer by alkalization (final dispersion pH > 13) and can be switched back after neutralization (final dispersion pH <8). Multiple structural changes at different pH values (≈9.6, ≈13) are observed through UV-Vis and CD spectral measurements, as well as other controlled experiments. Exploration of the CP synthesis kinetics suggests that the covalent bond formation is rapid and then the conformation of the CP materials would continuously evolve. The reaction stoichiometry investigation shows that the formation of CP materials with chirality inversion behavior requires the balancing between different coordination and polymerization processes. This study provides insights into the potential of inorganic stereochemistry in developing promising functional materials.
响应性手性体系因其在生物学、光电子学、光子学及相关领域的多种应用潜力而备受关注。在此，我们展示了通过改变pH值实现金-银-半胱氨酸（AuAg-cys）配位聚合物（CP）的可逆手性反转。该聚合物可通过将HAuCl和AgNO与L-半胱氨酸（或D-半胱氨酸）以适当比例在水中（或其他表面活性剂溶液）混合制得。圆二色性（CD）光谱用于记录AuAg-L-半胱氨酸对映体（记为L0.06）的强光学活性，通过碱化（最终分散液pH>13）可将其转换为相应D0.06对映体的光学活性，中和后（最终分散液pH<8）又可转换回原来的活性。通过紫外可见光谱和CD光谱测量以及其他对照实验，观察到在不同pH值（≈9.6，≈13）下的多种结构变化。对CP合成动力学的探索表明，共价键形成迅速，然后CP材料的构象会持续演变。反应化学计量学研究表明，具有手性反转行为的CP材料的形成需要不同配位和聚合过程之间的平衡。本研究为无机立体化学在开发有前景的功能材料方面的潜力提供了见解。
