A fresh look on helicenes' enantiomerization process with a focus on ring conformation reveals that it can be described as a step-by-step mechanism in which maximal distortion is consecutively transferred along the helicene skeleton, head to tail. Density functional theory methods were used to compute the enantiomerization pathway, and continuous symmetry measures were applied to quantify the distortion of even-number helicenes with 8-14 rings. Our findings show that the distortion wave is additive - the process always starts from one edge of the helicene and progresses along the rings until the other edge is reached. As more rings are added to the helicene, extra steps are appended to the distortion wave. Implications of this fundamental process are discussed in light of similar natural phenomena from polymer dynamics to snake locomotion.
Bibliographical noteFunding Information:
The work in Israel was supported by the Israel Science Foundation (grant no. 411/15). I.T-A. sincerely thanks Sagiv Barhoom (The Open University) for his help in programming and Itay Zandbank and Devora Witty (The scientific software company, Israel, http://www.chelem.co.il ) for their help in programming the CSM code. The work in Mexico was supported by Grant SEP-Cinvestav-2018-57. I.L.G. thanks support from DGTIC-UNAM under Project LANCAD-UNAM-DGTIC-049 and CONACYT-Mexico under Project 285821. J.B. thanks CONACYT for his PhD fellowship. An online CSM calculator is available at: http://csm.ouproj.org.il .