CC BY 4.0 · Synlett 2023; 34(10): 1122-1128
DOI: 10.1055/a-1928-4902
cluster
Dispersion Effects

Enhancement of London Dispersion in Frustrated Lewis Pairs: Towards a Crystalline Encounter Complex

Flip Holtrop‡
a   Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands
,
Christoph Helling‡
a   Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands
,
Martin Lutz
b   Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
,
Nicolaas P. van Leest
a   Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands
,
Bas de Bruin 
a   Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands
,
J. Chris Slootweg  ∗
a   Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands
› Author AffiliationsThis work was supported by the Council for Chemical Sciences of the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (The Netherlands Organization for Scientific Research, NWO/CW) by a VIDI grant (J.C.S.), the Nationale Wetenschapsagenda (Dutch Research Agenda, NWA) Idea Generator grant (J.C.S.), and by a postdoc fellowship (C.H.) of the Deutscher Akademischer Austauschdienst (German Academic Exchange Service, DAAD). The X-ray diffractometer was financed by NWO.
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Abstract

The encounter complex, i.e., the pre-organized assembly consisting of a Lewis acid and a Lewis base, is a fundamental concept in frustrated Lewis pair (FLP) chemistry. However, this donor–acceptor complex is challenging to study due to its transient nature. Here, we present a combined theoretical and experimental investigation on the potential isolation of an encounter complex enabled by enhancement of London dispersion forces between a sterically encumbered Lewis acid and base pair. Guided by computational analyses, the FLP originating from the bulky triarylamine N(3,5-tBu2C6H3)3 and the novel triarylborane B(3,5-tBu2C6H3)3 was investigated, leading to the isolation of a 1:1 co-crystal of both FLP components.

Key words

frustrated Lewis pairs - encounter complex - London dispersion forces - Lewis acid - Lewis base

Supporting Information



Publication History

Received: 15 July 2022

Accepted after revision: 19 August 2022

Accepted Manuscript online:
22 August 2022

Article published online:
11 October 2022

© 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by/4.0/)

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