London Dispersion Favors Sterically Hindered Diarylthiourea Conformers in Solution.

Lars Rummel, Marvin H J Domanski, Heike Hausmann, Jonathan Becker, Peter R Schreiner

Angewandte Chemie (International ed. in English) 2022 Jul 18

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We present an experimental and computational study on the conformers of N,N'-diphenylthiourea substituted with different dispersion energy donor (DED) groups. While the unfolded anti-anti conformer is the most relevant for thiourea catalysis, intramolecular noncovalent interactions counterintuitively favor the folded syn-syn conformer, as evident from a combination of low-temperature nuclear magnetic resonance measurements and computations. In order to quantify the noncovalent interactions, we utilized local energy decomposition analysis and symmetry-adapted perturbation theory at the DLPNO-CCSD(T)/def2-TZVPP and sSAPT0/6-311G(d,p) levels of theory. Additionally, we applied a double-mutant cycle to experimentally study the effects of bulky substituents on the equilibria. We determined London dispersion as the key interaction that shifts the equilibria towards the syn-syn conformers. This preference is likely a factor why such thiourea derivatives can be poor catalysts. © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

Citation

Lars Rummel, Marvin H J Domanski, Heike Hausmann, Jonathan Becker, Peter R Schreiner. London Dispersion Favors Sterically Hindered Diarylthiourea Conformers in Solution. Angewandte Chemie (International ed. in English). 2022 Jul 18;61(29):e202204393