A pyrene-functionalized foldamer: structural impact and recognition properties supported by donor–acceptor interactions

Abstract

An electroactive and luminescent foldamer based on an oligopyridine biscarboxamide skeleton was synthesized and characterised. Its conformation in the solid state proved to be strongly affected by the peripheral pyrene units. The latter also endow the target derivative with recognition abilities toward electron-withdrawing molecules, which allow tuning of the spectroscopic properties of the foldamer.

Metalla‐Assembled Electron‐Rich Tweezers: Redox‐Controlled Guest Release Through Supramolecular Dimerization

“…[16] To further study the stability of the dimeric (NaphM 4 L 2 ) 2 species,w ei nvestigated its behavior in the presence of DCTNF,a ne lectron-poor unit known to interact strongly with electron-rich derivatives. [17] Interestingly,u pon addition of 4equiv of DCTNF to as olution of (NaphM 4 L 2 ) 2 (c = 10 À3 m,MeOD), the 1 HNMR spectrum appeared significantly simplified (Figure 5d), illustrating the dissociation of the dimeric species.M oreover,t he resulting a and b protons showed chemical shifts similar to those of the NaphM 4 L 2 monomer (Figure 5c), while signals corresponding to the DTF core were upfield-shifted. This observation implies an intercalation of the electron-poor DCTNF plane between both DTF tips of the NaphM 4 L 2 monomer.A 1 HDOSY NMR experiment from which diffusion coefficients of 3.07·10 À10 m 2 s À1 and 3.73·10 À10 m 2 s À1 could be extracted for the host and the guest, respectively (Figure 5d and Figure S17), confirms 1) the drastic decrease of the selfassembly radius size,w hich is now comparable to the one of the NaphM 4 L 2 monomer,a nd 2) the strong host-guest interaction.…”

“…To further study the stability of the dimeric (NaphM 4 L 2 ) 2 species, we investigated its behavior in the presence of DCTNF, an electron‐poor unit known to interact strongly with electron‐rich derivatives . Interestingly, upon addition of 4 equiv of DCTNF to a solution of (NaphM 4 L 2 ) 2 ( c =10 −3 m , MeOD), the 1 H NMR spectrum appeared significantly simplified (Figure d), illustrating the dissociation of the dimeric species.…”

Redox-controlled hybridization of helical foldamers

“…The latter skeleton was selected for its ability to hybridize with a moderate dimerization constant, [32,33] its transparency in the visible range, and its redox inactivity in a wide range of potentials. [34] From the resulting compound 3 (Scheme 1), we demonstrate herein an unprecedented control over the dimerization equilibrium of a foldamer through redox stimulation. The synthesis of target foldamer 3 is depicted in Schemes 1 and S1.…”

Electron-rich Coordination Receptors Based on Tetrathiafulvalene Derivatives: Controlling the Host–Guest Binding

“…We also studied the behavior of the electron-rich Pd2(DTFa)2 4+ cavity for complexing the electron-deficient 9dicyanomethylene-2,4,7-trinitrofluorene (DCTNF) -acceptor molecule, a unit which is known to interact strongly with electron-rich derivatives. 111 A UV-vis titration completed by a Job plot analysis revealed the formation of a 1:1 host-guest complex with an association constant of Ka = 7.8 (± 0.9) x 10 5 in CH2Cl2 (Figure 10e). This recognition process was followed by cyclic voltammetry experiments (Figure 10d).…”