A1 Journal article (refereed)
Dynamic Refolding of Ion-Pair Catalysts in Response to Different Anions (2019)
Neuvonen, A. J., Noutsias, D., Topić, F., Rissanen, K., Földes, T., Pápai, I., & Pihko, P. M. (2019). Dynamic Refolding of Ion-Pair Catalysts in Response to Different Anions. Journal of Organic Chemistry, 84(23), 15009-15019. https://doi.org/10.1021/acs.joc.9b01980
JYU authors or editors
Publication details
All authors or editors: Neuvonen, Antti J.; Noutsias, Dimitris; Topić, Filip; Rissanen, Kari; Földes, Tamás; Pápai, Imre; Pihko, Petri M.
Journal or series: Journal of Organic Chemistry
ISSN: 0022-3263
eISSN: 1520-6904
Publication year: 2019
Volume: 84
Issue number: 23
Pages range: 15009-15019
Publisher: American Chemical Society
Publication country: United States
Publication language: English
DOI: https://doi.org/10.1021/acs.joc.9b01980
Publication open access: Not open
Publication channel open access:
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/65607
Abstract
Four distinct folding patterns were identified in two foldamer-type urea-thiourea catalysts bearing a basic dimethylamino unit by a combination of X-ray crystallography, solution NMR studies, and computational studies (DFT). These patterns are characterized by different intramolecular hydrogen bonding schemes that arise largely from different thiourea conformers. The free base forms of the catalysts are characterized by folds where the intramolecular hydrogen bonds between the urea and the thiourea units remain intact. In contrast, the catalytically relevant salt forms of the catalyst, where the catalyst forms an ion pair with the substrate or substrate analogues, appear in two entirely different folding patterns. With larger anions that mimic the dialkyl malonate substrates, the catalysts maintain its native fold both in the solid state and in solution, but with smaller halide anions (fluoride, chloride and bromide), the catalysts fold around the halide anion (anion receptor fold) and the intramolecular hydrogen bonds are disrupted. Titration of catalyst hexafluoroacetylacetonate salt with tetra-n-butylammonium chloride results in dynamic refolding of the catalyst from the native fold to the anion receptor fold.
Keywords: anions; catalysis; crystallography; x-ray crystallography
Free keywords: catalysis; folding, anion binding; X-ray; solution structures; conformational change
Contributing organizations
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Ministry reporting: Yes
Reporting Year: 2019
JUFO rating: 2