Study of the self-association of molecular tweezers bearing two different arms: influence of the stereoelectronic effects of the arm substituents

Béatrice Legouin (1) , Arnaud Bondon (1) , Clement Orione (2) , Solenn Ferron (1) , Philippe Uriac (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 ScanMAT - Synthèse Caractérisation Analyse de la Matière

In the general field of molecular recognition, the self-assembly of a tweezer bearing a R(+) usnic acid arm and a substituted 1,8-naphthalimide moiety as a second arm was investigated through a H-1 NMR study. Two self-association modes were evidenced either the usnic acid arms (mode A) or the naphthalimide ones (mode B) were face to face in the center of the dimer. The existence of a third non-symmetrical mode (mode C) has not been evidenced experimentally. The behavior of these tweezers was discussed taking into account the electronic density of the naphtalimide arms and the slow mode A/mode B exchange rate (EXSY experiments). Only the mode A was observed when naphthalimide was either non-substituted (1) or substituted by Br (2). With one or two electrodonating substituents (OCH3 (3) or (OCH3)(2) (4) or N(CH3)(2) (5)) both modes A and B occured in a 50/50 ratio. This ratio depended on temperature for tweezer 3.

Keywords: Supramolecular recognition; H-1 NMR; Self-association; Tweezer

Domains: Chemical Sciences

Béatrice Legouin, Arnaud Bondon, Clement Orione, Solenn Ferron, Philippe Uriac. Study of the self-association of molecular tweezers bearing two different arms: influence of the stereoelectronic effects of the arm substituents. Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2020, 96 (1-2), pp.101-109. ⟨10.1007/s10847-019-00954-2⟩. ⟨hal-02391901⟩