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2 results on '"proton brake"'

1. N−C Axially Chiral Anilines: Electronic Effect on Barrier to Rotation and A Remote Proton Brake.

Author

Iwasaki, Yumiko, Morisawa, Ryuichi, Yokojima, Satoshi, Hasegawa, Hiroshi, Roussel, Christian, Vanthuyne, Nicolas, Caytan, Elsa, and Kitagawa, Osamu

Subjects
*ACTIVATION energy, *CHEMICAL kinetics, *CHEMICAL reactions, *ROTATIONAL barriers, *FORCED vibration (Mechanics)
Abstract

Abstract: N‐Aryl‐N‐methyl‐2‐tert‐butyl‐6‐methylaniline derivatives exhibit a rotationally stable N−C axially chiral structure and the rotational barriers around an N−C chiral axis increased with the increase in electron‐withdrawing character of para‐substituent on the aryl group. X‐ray crystal structural analysis and the DFT calculation suggested that the considerable change of the rotational barriers by the electron effect of para‐substituents is due to the disappearance of resonance stabilization energy caused by the twisting of para‐substituted phenyl group in the transition state. This structural property of the N−C axially chiral anilines was employed to reveal a new acid‐decelerated molecular rotor caused by the protonation at the remote position (remote proton brake). [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
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2. N−C Axially Chiral Anilines: Electronic Effect on Barrier to Rotation and A Remote Proton Brake

Author

Osamu Kitagawa, Christian Roussel, Hiroshi Hasegawa, Elsa Caytan, Ryuichi Morisawa, Satoshi Yokojima, Yumiko Iwasaki, Nicolas Vanthuyne, Shibaura Institute of Technology, Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), JSPS KAKENNHI [C17K08220], Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
Proton, 010405 organic chemistry, Chemistry, Aryl, amines, Organic Chemistry, Protonation, General Chemistry, Electron, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, Crystallography, Axial chirality, density functional calculations, electronic effect, Electronic effect, proton brake, Phenyl group, axial chirality, Axial symmetry
Abstract

International audience; N-Aryl-N-methyl-2-tert-butyl-6-methylaniline derivatives exhibit a rotationally stable N-C axially chiral structure and the rotational barriers around an N-C chiral axis increased with the increase in electron-withdrawing character of para-substituent on the aryl group. X-ray crystal structural analysis and the DFT calculation suggested that the considerable change of the rotational barriers by the electron effect of para-substituents is due to the disappearance of resonance stabilization energy caused by the twisting of para-substituted phenyl group in the transition state. This structural property of the N-C axially chiral anilines was employed to reveal a new acid-decelerated molecular rotor caused by the protonation at the remote position (remote proton brake).

Published
2018
Full Text
View/download PDF

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