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Updated: May 8, 2026

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers
Published on: August 18, 2017
Conformational study of an axially chiral Salen ligand in solution using two-photon circular dichroism and the
Carlos Díaz1, Lorenzo Echevarria, Florencio E Hernández
1Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 32816-2366, USA.
Abstract:
Herein we report on the conformational study of a chiral Salen ligand, AFX-155, in THF solution using two-photon absorption (TPA) and, even more importantly, two-photon circular dichroism (TPCD). The fragment-recombination approach (FRA), employed to perform computations on half-AXF-155 (AXF-169') and the center (C-AXF-155), allowed us to overcome the current computational limitations found in calculations of the TPCD spectra of large molecules. The comparative experimental-theoretical analysis of AXF-155 showed that its TPA is mainly determined by AXF-169' and validated, through TPCD, the presence of the two dominant Trans_R-Intra(NHB)//Trans_R-Extra(HB) and Trans_R-Intra(NHB)//Trans_R-Extra(NHB) structure in THF with a ΔΔ propeller chirality on the diphenylamine moieties at the end of each AXF-169'. The application of FRA for the analysis of the TPCD spectra of large chiral molecules has been proven to be effective.
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