Dynamic helical polymers have attracted the attention of the scientific community during the last decades due to their stimuli responsive properties and the functionality attributed to the helical scaffold.1 Thus, while helical sense and elongation of dynamic helical polymers can be altered by their interaction with external stimuli, the helical scaffolds adopted by the polymers are responsible of their applications in different fields such as asymmetric synthesis, chiral recognition, or chiral stationary phases in HPLC.1 Importantly, to create a dynamic helical polymer with a good performance in certain applications it is necessary to know its secondary structure, which also allows establishing a structure/function relationship in this kind of materials.2 To obtain an approximated 3D structure of a helical polymer such as a poly(phenylacetylene), a combination of the information obtained from different structural techniques —UV-vis, circular dichroism (CD), vibrational circular dichroism (VCD), Raman, Raman optical activity (ROA), differential scanning calorimetry (DSC) and atomic force microscopy (AFM)— is needed. This fact is due to the complexity of the helical scaffolds found in PPAs, which are made by two coaxial helices: an internal helix described by the polyene backbone and an external one described by the pendants, which, depending on the stereoregularity of the polyene backbone, can rotate in the same (cis-cisoidal) or opposite directions (cis-transoidal).3-4 Herein, I will show how to elucidate the secondary structure of a helical polymer by solving the information puzzle obtain from different techniques. Moreover, the knowledge of the secondary structure will allow to control other structural parameters such as the dynamic behavior and stimuli responsive properties.5
Acknowledgements
We thank MINECO (PID2022-136848NB-I00), Xunta de Galicia (ED431C 2022/21Centro Singular de Investigación de Galicia acreditación 2023-2027, ED431G 2023/03, ED431G 2023/06,