Planar–rotor architecture based pyrene–vinyl–tetraphenylethylene conjugated systems: photophysical properties and aggregation behavior

Abstract

Four pyrene-vinyl-tetraphenylethylene based conjugated materials were synthesized and characterized by FT-IR, NMR, and mass spectroscopy. The photophysical (including absorption, fluorescence, and fluorescence lifetime) and aggregation properties in tetrahydrofuran were investigated. The photophysical and aggregation behavior depends on the spacer, substituent, and also the architecture (mono or tetra-branched) of the molecule. The vinyl spacer mono-branched compound is aggregation induced emission (AIE) active (αAIE = ∼6). Vinyl spacer tetra-branched compounds are AIE inactive, but their emitting efficiency is good in both solution (Φfl = 63%) phase and in the aggregated state (Φfl = 43%). Phenylvinyl spacer tetra-branched compounds emit light strongly in solution (Φfl = 92%), but not in the aggregated state (Φfl = 8%). They are shown to be thermally stable and emit light in the green region (500-550 nm). The results of cyclic voltammetry measurements of these materials showed irreversible oxidation waves, and have high HOMO energy levels (-5.66 to -5.53 eV).

Synthesis of 1,1’‐diphenyl‐2‐thienyl‐2’‐(4‐substituted‐styryl)ethenes via oxidative Heck coupling reaction and photophysical studies

“…The construction of a pyrene-vinyl-TPE-based planar-rotor (4) was reported by Binay K. Ghoarai and his co-workers. [7] The AIE of this molecule was not observed due to the pi-pi stacking of the pyrene framework, but it showed excellent emitting efficiency in the green region in solution (92 %) and in the aggregated state (8 %). It was also proved to be thermally stable under normal conditions.…”

“…Notably, C7 substituted coumarin-TPE showed red-shift and large Stokes shift in its absorption spectrum. Fullcolor tunable aryl TPEs (7) were synthesized with many different substituted groups in the aryl ring. [8] The donor and acceptor were selected to examine.…”

Pyrene-Based AIE Active Materials for Bioimaging and Theranostics Applications

“…Apart from the demonstrated AIE-based bioimaging utilities, many studies of the pyrene derivatives focused only on the analyte tuned cellular imaging but not the AIE effect [ 102 , 103 , 104 , 105 , 106 ]. On the other hand, some studies of the pyrene-based moieties have described their AIE properties towards diverse optoelectronic applications [ 107 , 108 , 109 , 110 , 111 ] and their potential as the bioimaging candidates in the future.…”

Intriguing H-Aggregates of Heptamethine Cyanine for Imaging-Guided Photothermal Cancer Therapy

“…Previous studies have demonstrated that planar pyrene and its derivatives could form π–π stacking in concentrated solutions to cause fluorescence quenching. − They are of particular interest as regulators for the creation of supramolecular aggregates with desired photothermal properties by tuning the intermolecular interactions of pyrene–near infrared (NIR) dye conjugates . In this communication, we do that by guiding the H-type aggregation of heptamethine cyanine (Cy7) molecules, in which planar pyrene is introduced into the central cyclohexenyl chloro group in Cy7 (Figure ).…”