Hirose, DaisukeIsobe, AsahiQuiñoá Cabana, EmilioFreire Iribarne, Félix ManuelMaeda, Katsuhiro2019-06-172020-05-072019-05-07Hirose, D., Isobe, A., Quiñoá, E., Freire, F., & Maeda, K. (2019). Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State. Journal Of The American Chemical Society, 141(21), 8592-8598. doi: 10.1021/jacs.9b031770002-7863http://hdl.handle.net/10347/18881This is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, Copyright © 2019 American Chemical Society after peer review and technical edityng by the publisher. To access the final edited and published work see: https://pubs.acs.org/doi/10.1021/jacs.9b03177An unprecedented three-state switchable chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) was developed using a helical poly(phenylacetylene) bearing a chiral (R)-α-methoxyphenylacetic acid residue as the pendant (poly-1). The left- and right-handed helical conformations were induced in poly-1-based CSP upon coordination with a catalytic amount of soluble sodium and cesium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate salts (MBArF), respectively, which are soluble in the HPLC conditions [hexane–2-propanol (95:5, v/v)]. The switch between the two different helical states of poly-1 can be easily achieved by rinsing the poly-1-based CSP with MeOH and the subsequent addition of the proper MBArF salt. Using this dynamic helical CSP, we demonstrate how changes on the orientation of the secondary structure of a chiral polymer (right-handed, left-handed, and racemic helices) can alter and even invert the elution order of the enantiomers. This study was done without adding chiral additives or changing the mobile phase, which could produce changes on the retention times and make it more difficult to determine the role of the secondary structure during the chiral recognition processengCopyright © 2019 American Chemical Societyjournal article10.1021/jacs.9b031771520-5126open access