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


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Publication details

All authors or editorsNeuvonen, Antti J.; Noutsias, Dimitris; Topić, Filip; Rissanen, Kari; Földes, Tamás; Pápai, Imre; Pihko, Petri M.

Journal or seriesJournal of Organic Chemistry

ISSN0022-3263

eISSN1520-6904

Publication year2019

Volume84

Issue number23

Pages range15009-15019

PublisherAmerican Chemical Society

Publication countryUnited States

Publication languageEnglish

DOIhttps://doi.org/10.1021/acs.joc.9b01980

Publication open accessNot 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.


Keywordsanionscatalysiscrystallographyx-ray crystallography

Free keywordscatalysis; folding, anion binding; X-ray; solution structures; conformational change


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Ministry reportingYes

Reporting Year2019

JUFO rating2


Last updated on 2024-08-01 at 21:39