Rational Topological Design for Fluorescence Enhancement upon Aggregation of Distyrylfuran Derivatives

Abstract

A series of 2,5-distyrylfuran derivatives bearing pentafluorophenyl- and cyanovinyl units have been synthesized for aggregation-induced emission (AIE). The effect of the type and extent of the supramolecular connections on the AIE of the furan derivatives were examined and correlated with their X-ray crystal structures. It was found that the simultaneous presence of cyano and perfluorophenyl units strongly enhances the fluorescence upon aggregation. Single-crystal X-ray diffraction analysis confirmed that CH⋅⋅⋅F, F⋅⋅⋅F, CH⋅⋅⋅nitrile, Ar⋅⋅⋅ArF (Ar=aryl, ArF =fluoroaryl), and nitrile⋅⋅⋅ArF intra- and intermolecular interactions drive the topology of the molecule and that solid-state supramolecular contacts favor AIE of the furan derivatives.

The Strong Light‐Emission Materials in the Aggregated State: What Happens from a Single Molecule to the Collective Group

“…As shown in Figure , and with planar structures exhibit ACQ properties for the strong π–π stacking interactions. Upon the incorporation of CN unit, the opposite AIE activities of the resultant molecules ( 25 and 26 ) are apparent, mainly due to the slightly distorted configurations with the cyano groups twisted from the plane (defined by the furan ring) . Meanwhile, in the aggregated state, the intermolecular CN⋯Ar F and CF⋯Ar F interactions and hydrogen bonds rigidify the configuration largely, directly contributing to the observed AIE phenomena.…”

Hydrogen‐Bond and Supramolecular‐Contact Mediated Fluorescence Enhancement of Electrochromic Azomethines

“…The emission enhancement modes have principally been from aromatic stacking or weak binding of an analyte . Although it was recently demonstrated that supramolecular contacts that drive crystallization in the solid state can be used for AIE enhancement, only a limited number of examples have used such contacts for enhancing the fluorescence of azomethines. These have relied on the imine nitrogen to promote intermolecular =N⋅⋅⋅HS− and =N⋅⋅⋅HC− bonds in addition to intramolecular =N⋅⋅⋅HO− supramolecular contacts.…”

Topological and packing mode modification for solid-state emission enhancement of bis(perfluorostyryl)furan derivatives

“…The absorption and emission of F1 in dilute solution and when aggregated were subsequently evaluated. 33 The nitrile group therefore quenches the fluorescence in solution with the extent of deactivation contingent on the number of nitrile (Fig. As shown in Figure 4, the absorption spectrum of F1 in homogenous THF solution shows a non-structured absorption band at 395 nm.…”

“…As shown in Figure 4, the absorption spectrum of F1 in homogenous THF solution shows a non-structured absorption band at 395 nm. 33 In solution, the fluorescence quantum yield (fl) decreased ca. 33 Water was added to THF solutions to aggregate FI and evaluate the resulting change in emission intensity and absorption.…”

“…Although, both the intrinsic and intermolecular deactivation modes that reduce the emission of conventional fluorophores in the solid-state are well-known, their effects remain relatively unexplored for fluorophores that exhibit emission enhancement upon aggregation. 33 The asymmetry of F1 and its supramolecular contacts make it an ideal candidate for assessing the contribution of each contact towards the solidstate emission enhancement. 12,13 It is therefore important to establish sound structure-solid state emission efficiency relationships for the design and preparation of -conjugated compounds for ultimately improving emitting device efficiency.…”