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Folding a Molecular Strand into a Trefoil Knot of Single Handedness with Co(II)/Co(III) Chaperones.
Zhong, Jiankang; Sun, Zhanhu; Zhang, Liang; Whitehead, George F S; Vitorica-Yrezabal, Iñigo J; Leigh, David A.
Afiliación
  • Zhong J; Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
  • Sun Z; School of Chemistry and Molecular Engineering, East China Normal University, 200062 Shanghai, China.
  • Zhang L; School of Chemistry and Molecular Engineering, East China Normal University, 200062 Shanghai, China.
  • Whitehead GFS; Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
  • Vitorica-Yrezabal IJ; Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
  • Leigh DA; School of Chemistry and Molecular Engineering, East China Normal University, 200062 Shanghai, China.
J Am Chem Soc ; 146(31): 21762-21768, 2024 Aug 07.
Article en En | MEDLINE | ID: mdl-39060953
ABSTRACT
We report the synthesis of a right-handed (Δ-stereochemistry of strand crossings) trefoil knot from a single molecular strand containing three pyrazine-2,5-dicarboxamide units adjacent to point-chiral centers and six pyridine moieties. The oligomeric ligand strand folds into an overhand (open-trefoil) knot through the assistance of coordinatively dynamic Co(II) "chaperones" that drive the formation of a three-metal-ion circular helicate. The entangled structure is kinetically locked by oxidation to Co(III) and covalently captured by ring-closing olefin metathesis to generate a trefoil knot of single topological handedness. The stereochemistry of the strand crossings in the metal-coordinated overhand knot is governed by the stereochemistry of the point-chiral carbon centers in the ligand strand. The overhand and trefoil knots were characterized by NMR spectroscopy, mass spectrometry, and X-ray crystallography. Removal of the metal ions from the knot, followed by hydrogenation of the alkene, yielded the wholly organic trefoil knot. The metal-free knot and parent ligand were investigated by circular dichroism (CD) spectroscopy. The CD spectra indicate that the topological stereochemistry of the knot has a greater effect on the asymmetry of the chromophore environment than do the point-chiral centers of the strand.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2024 Tipo del documento: Article Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2024 Tipo del documento: Article Pais de publicación: Estados Unidos