1H NMR and computational study of the conformations in solution of one host/guest complex formed with an usnic acid tweezer and 2,4,7-trinitro-9-fluorenone (TNF)

Eric Hitti (1) , Béatrice Legouin (2) , Jérôme Graton (3) , Denis Jacquemin (4, 3) , Philippe Uriac (2)

1 LTSI - Laboratoire Traitement du Signal et de l'Image
2 ISCR - Institut des Sciences Chimiques de Rennes
3 CEISAM - Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation
4 IUF - Institut Universitaire de France

In a host-guest model formed by a molecular tweezer 4, bearing two usnic acid units, and TNF, the TNF protons chemical shifts are measured at various temperatures. With the help of a computational study, the geometries of complexation of this host-guest system are identified and their TNF protons chemical shifts calculated. Data analysis led to conclude that in solution two types of conformations are present: the “lateral” one (similar to the structure found in the solid state) and the “longitudinal” one in which the TNF is less engaged inside the host. The proportion of the latter increases with decreasing temperatures

Keywords: Conformers; DFT-D; NMR; Stacking

Domains: Chemical Sciences; Theoretical and/or physical chemistry

Eric Hitti, Béatrice Legouin, Jérôme Graton, Denis Jacquemin, Philippe Uriac. 1H NMR and computational study of the conformations in solution of one host/guest complex formed with an usnic acid tweezer and 2,4,7-trinitro-9-fluorenone (TNF). Tetrahedron, 2016, 72 (22), pp.2890-2894. ⟨10.1016/j.tet.2016.03.100⟩. ⟨hal-01298758⟩