Hindered Tetraphenylethylene Helicates: Chiral Fluorophores with Deep‐Blue Emission, Multiple‐Color CPL, and Chiral Recognition Ability

Abstract

New hindered tetraphenylethylene (TPE) helicates with substitution at 2,6-position of phenyl rings were designed and synthesized. Due to the increased hindrance, the TPE helicates emit strong deep-blue to violet fluorescence both in the solid state and in solution, and could be resolved into enantiomers that emit strong and multicolor circularly polarized luminescence (CPL), and exhibit a high enantioselective recognition of chiral tartaric acid and its derivatives. Surprisingly, the derived helicate tetramines possess amino groups with an unpredented planar structure and sp 2hybridized nitrogen, arousing the change between AIE effect and ACQ phenomenon through photoinduced electron transfer (PET). With advantages of short synthetic route, many modification positions, deep-blue to violet emission, wide CPL tuning, and high chiral recognition ability, the hindered TPE helicates show broad prospects as chiral materials.

Unprecedented TPE-Embedded Butterfly Bis-Crown Ether with Controllable Conformation and Supramolecular Chiroptical Property

“…The inherent helical chirality of TPE is widely recognized when the rotation of the phenyl rings is constrained. [36] Inspired by the chirality amplification phenomenon observed in supramolecular systems, we aim to utilize host-guest interaction between chiral guest molecule and achiral host to induce and amplify the chirality of our macrocycles. [37][38][39][40][41] Additionally revealing the chirality of amino acid-containing copolymers poses significant challenges due to the absence of chromophoric groups and racemic mixture of amino acid enantiomers.…”

Enantioselective determination of chiral acids and amino acids by chiral receptors with aggregation-induced emissions

“…[26][27][28][29][30][31][32] Combining optically pure groups with the AIEgens can endow the probes with chiral-sensing ability via the detection of fluorescence intensity or wavelength changes. 1,7,33 For example, Zheng and co-workers reported several TPE-based chiral receptors that could enantioselectively discriminate chiral amines or acids. 7,[34][35][36] Recently, some chiral TPE derivatives bearing two optically pure 1-phenylethylamine functionalities were constructed by our group to obtain excellent enantioselectivity and sensitivity for chiral amino acids through supramolecular interaction with calixarene.…”

Cage-Confinement Induced Emission Enhancement

“…Such luminophores are often called AIEgens. In general, AIE is a result of the suppression of nonradiative decay channels (intramolecular rotations and/or vibrations) of excited AIEgen aggregates. − A plethora of organic materials with AIE properties have been reported since the pioneering work of Tang, which include small organic blocks, , macrocycles, , helicates, − and polymers, , which present promising candidates in high-tech applications such as optoelectronic devices, , sensors, − and biomedicine , etc. The straightforward and efficient means to activate the AIE process or enlarge the AIE effect is to restrict any intramolecular motions that consume energy, including intramolecular rotations and vibrations .…”