Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy

The microwave Fourier transform spectrum of butan-2,3-ol has been recorded in the range 5-18 GHz. The molecule possesses two chiral centres and exists in two distinct forms, one of which is homochiral ((R,R) or (S,S)) and is overall chiral, and the other which is heterochiral ((R,S) or (S,R)) and is...

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Main Authors: Paul, J, Hearn, I, Howard, B
Format: Journal article
Language:English
Published: 2007
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author Paul, J
Hearn, I
Howard, B
author_facet Paul, J
Hearn, I
Howard, B
author_sort Paul, J
collection OXFORD
description The microwave Fourier transform spectrum of butan-2,3-ol has been recorded in the range 5-18 GHz. The molecule possesses two chiral centres and exists in two distinct forms, one of which is homochiral ((R,R) or (S,S)) and is overall chiral, and the other which is heterochiral ((R,S) or (S,R)) and is overall meso. Detailed ab initio calculations enabled investigation of the relative stability of the many conformations exhibited by each form of the molecule. It is shown that the lowest energy forms in each case possess an internal hydrogen bond. The spectrum of the heterochiral (meso) form could be readily identified and analysed. The homochiral form, however, exhibits a tunnelling motion of about 1 GHz, in which the hydrogen bonded OH groups interchange their roles. Deuteration of one of these OH protons quenches the tunnelling motion, aiding the assignment of the spectrum. In all cases, deuteration of the hydroxyl groups was used to locate the positions of the OH hydrogen atoms and helped to confirm the identification of the conformers present.
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spelling oxford-uuid:2ff3b91f-0cc7-4815-9b56-073de7f616332022-03-26T12:58:40ZChiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopyJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2ff3b91f-0cc7-4815-9b56-073de7f61633EnglishSymplectic Elements at Oxford2007Paul, JHearn, IHoward, BThe microwave Fourier transform spectrum of butan-2,3-ol has been recorded in the range 5-18 GHz. The molecule possesses two chiral centres and exists in two distinct forms, one of which is homochiral ((R,R) or (S,S)) and is overall chiral, and the other which is heterochiral ((R,S) or (S,R)) and is overall meso. Detailed ab initio calculations enabled investigation of the relative stability of the many conformations exhibited by each form of the molecule. It is shown that the lowest energy forms in each case possess an internal hydrogen bond. The spectrum of the heterochiral (meso) form could be readily identified and analysed. The homochiral form, however, exhibits a tunnelling motion of about 1 GHz, in which the hydrogen bonded OH groups interchange their roles. Deuteration of one of these OH protons quenches the tunnelling motion, aiding the assignment of the spectrum. In all cases, deuteration of the hydroxyl groups was used to locate the positions of the OH hydrogen atoms and helped to confirm the identification of the conformers present.
spellingShingle Paul, J
Hearn, I
Howard, B
Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy
title Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy
title_full Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy
title_fullStr Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy
title_full_unstemmed Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy
title_short Chiral recognition in a single molecule: a study of homo and heterochiral butan-2,3-diol by Fourier transform microwave spectroscopy
title_sort chiral recognition in a single molecule a study of homo and heterochiral butan 2 3 diol by fourier transform microwave spectroscopy
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AT hearni chiralrecognitioninasinglemoleculeastudyofhomoandheterochiralbutan23diolbyfouriertransformmicrowavespectroscopy
AT howardb chiralrecognitioninasinglemoleculeastudyofhomoandheterochiralbutan23diolbyfouriertransformmicrowavespectroscopy