Determination of the absolute configuration of conformationally flexible molecules by simulation of chiro-optical spectra: a case study.

Authors :: Mancinelli M
Franzini R
Renzetti A
Marotta E
Villani C
Mazzanti A
Source :: RSC advances [RSC Adv] 2019 Jun 10; Vol. 9 (32), pp. 18165-18175. Date of Electronic Publication: 2019 Jun 10 (Print Publication: 2019).
Publication Year :: 2019
Abstract: The assignment of the absolute configuration (AC) of two conformational flexible organic molecules by means of TD-DFT simulation of the electronic circular dichroism (ECD) spectra is presented. The factors leading to a reliable assignment were evaluated in the various steps of the process. The effects of different functionals and basis sets in the geometry optimization step is very limited in terms of the resulting optimized geometries, whereas the inclusion of the solvent in the calculations has a much larger effect on the correct evaluation of the conformational ratio. B3LYP and M06-2x were found to be the most accurate functionals for geometry optimization. CAM-B3LYP and ωB97X-D provided the best results in the TD-DFT simulations.<br />Competing Interests: There are no conflicts to declare.<br /> (This journal is © The Royal Society of Chemistry.)

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