Triggering Gel Formation and Luminescence through Donor–Acceptor Interactions in a C₃‐Symmetric Tris(pyrene) System

Abstract

Straightforward modulation of the gelation, absorption and luminescent properties of a tris(pyrene) organogelator containing a C3 -symmetric benzene-1,3,5-tricarboxamide central unit functionalized by three 3,3'-diamino-2,2'-bipyridine fragments is achieved through donor-acceptor interactions in the presence of tetracyanoquinodimethane.

Tuning the Organogelating and Spectroscopic Properties of a C3‐Symmetric Pyrene‐Based Gelator through Charge Transfer

“…Indeed, for a staggered conformation, reminiscent of the one observed in the crystal structure of pyrene‐TCNQ 1:1 complex, [81] two CT bands arising at approx. 500 and 750 nm, very close to the experimentally reported values in pyrene‐TCNQ [69] and C 3 Pyr ‐TCNQ, [64] are clearly observed. However, such bands are not observed for the eclipsed conformation.…”

“…Tris(3,3’‐diamido‐2,2’‐bipyridine)‐benzene‐1,3,5‐tricarboxamide‐based C 3 compounds exhibit a strong propensity to form highly ordered nanostructures through combined intramolecular H‐bonds and intermolecular π–π interactions [58–64] . On the other hand, pyrene is known to interact with electron‐poor molecules such as TNF [47–50] and TCNQ [68, 69] .…”

“…Some of us have reported the original spectroscopic behavior of C 3 Pyr , [64] especially in the presence of the TCNQ acceptor. When a solution of C 3 Pyr in TCE is excited at 344 nm ( λ max (pyrene)), a single emission band centered at 515 nm is observed, which corresponds to the radiative relaxation of the tris(bipyridyl) core.…”

“…Electro‐ and photoactive BTABP derivatives affording functional gels and supramolecular aggregates have been described with tetrathiafulvalene (TTF) [58–61] and porphyrin substituents [62, 63] . The attachment of pyrene units at the periphery of BTABP platform has been recently reported by some of us together with its gel formation ability [64] . Compound C 3 Pyr (Scheme 1) forms gels in 1,1,2,2‐tetrachloroethane (TCE) at a critical gelation concentration (CGC) [65] of 65 mg mL −1 (4.26×10 −2 m ).…”

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

“…35,36 Pyrene can indeed return to the ground state through monomer, excimer or sometimes exciplex emissions after excitation. 37 As mentioned above, the solution of foldamer 1 (1.5 mM, CDCl3) turns green upon addition of acceptor 7 (Fig. 3d).…”