Enantioselective Complexation of Protonated Tyrosine by a Chiral Crown‐ether: The Nature of the Hydrogen Bonds Makes the Difference

Abstract: The complexes formed between (18‐crown‐6)‐tetracarboxylic acid, denoted as 18C6TA, and the two enantiomers of protonated tyrosine, L‐ and D‐Tyr, are studied in a cryogenic ion trap by combining mass spectrometry, laser spectroscopy, and DFT calculations. Both UV and IR photodissociation spectra indicate the formation of multiple isomers for each complex, some of them interconverting upon IR irradiation. Conformer‐selective vibrational spectroscopy reveals that all structures involve an internally hydrogen‐bonded folded structure of the crown ether. The complexes formed with L‐Tyr involve two NH…O interactions with the ether oxygen atoms, accompanied by two hydrogen bonds to the crown ether carboxylic function, one from the NH group and the other from the COOH group of tyrosine. The complexes formed with D‐Tyr show more conformational mobility: two out of the three lowest energy conformers observed are tripodal, with three NH…O interactions between the amino acid ammonium and the crown ether oxygens. An additional conformer shows only one NH…O interaction, but has two interactions involving one of the cavity COOH moieties, one with the NH and one with the phenol OH. The increased calculated stability of the complex made from (−) 18C6TA and L‐Tyr parallels its higher abundance in the mass spectrum of an isotopically labelled racemic mixture.

Standort
Deutsche Nationalbibliothek Frankfurt am Main
Umfang
Online-Ressource
Sprache
Englisch

Erschienen in
Enantioselective Complexation of Protonated Tyrosine by a Chiral Crown‐ether: The Nature of the Hydrogen Bonds Makes the Difference ; day:17 ; month:12 ; year:2024 ; extent:12
ChemPhysChem ; (17.12.2024) (gesamt 12)

Urheber
Vo, Kien X.
Hirata, Keisuke
Martínez‐Haya, Bruno
Oomens, Jos
Ishiuchi, Shun‐ichi
Fujii, Masaaki
Zehnacker, Anne

DOI
10.1002/cphc.202400880
URN
urn:nbn:de:101:1-2412171340110.531495680410
Rechteinformation
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Letzte Aktualisierung
15.08.2025, 07:37 MESZ

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Beteiligte

  • Vo, Kien X.
  • Hirata, Keisuke
  • Martínez‐Haya, Bruno
  • Oomens, Jos
  • Ishiuchi, Shun‐ichi
  • Fujii, Masaaki
  • Zehnacker, Anne

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