On the Nature of the Rotational Energy Barrier of Atropisomeric Hydrazides

Andrea Pellegrini; Laura Marcon; Paolo Righi; Giovanni Centonze; Chiara Portolani; Marco Capodiferro; Shilashi Badasa Oljira; Simone Manetto; Alessia Ciogli; Giorgio Bencivenni

doi:10.3390/molecules28237856

On the Nature of the Rotational Energy Barrier of Atropisomeric Hydrazides

Molecules. 2023 Nov 29;28(23):7856. doi: 10.3390/molecules28237856.

Authors

Andrea Pellegrini^{1

2}, Laura Marcon¹, Paolo Righi^{1

2

3}, Giovanni Centonze^{1

2}, Chiara Portolani^{1

2}, Marco Capodiferro¹, Shilashi Badasa Oljira⁴, Simone Manetto⁴, Alessia Ciogli⁴, Giorgio Bencivenni^{1

2

3}

Affiliations

¹ Department of Industrial Chemistry "Toso Montanari", Alma Mater Studiorum University of Bologna, Via P. Gobetti 85, 40129 Bologna, Italy.
² Center for the Chemical Catalysis-C3, Alma Mater Studiorum University of Bologna, Via P. Gobetti 85, 40129 Bologna, Italy.
³ National Interuniversity Consortium of Materials Science and Technology (INSTM), Bologna Research Unit, Via P. Gobetti 85, 40129 Bologna, Italy.
⁴ Department of Chemistry and Technologies of Drug, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.

Abstract

N-N atropisomers represent a useful class of compounds that has recently received important attention from many research groups. This article presents an in-depth analysis of the energy barrier needed for the racemization process of atropoisomeric hydrazides, combining an experimental and computational approach. The focus is on examining how electronic and steric factors impact the racemization process. The results obtained indicate that the barrier observed during the racemization process mainly arises from an increase in the p-orbital character of the nitrogen atoms.

Keywords: N-N atropisomers; dynamic-HPLC; hydrazides; racemization.

Grants and funding

DM 737/2021/Next Generation EU