Fluorescence Regulation and Photoresponsivity in AIEE Supramolecular Gels Based on a Cyanostilbene Modified Benzene‐1,3,5‐Tricarboxamide Derivative

Abstract

Supramolecular interactions play an important role in regulating the optical properties of molecular materials. Different arrangements of identical molecules can afford a more straightforward insight into the contributions of supramolecular interactions. Herein, a novel gelator, BTTPA, composed of a benzene‐1,3,5‐tricarboxamide (BTA) central unit functionalized with three cyanostilbenes is designed, which forms two kinds of gels in DMSO/water mixtures. Depending on the water volume content, the gels exhibit quite different aggregation‐induced emission enhancement (AIEE) properties, with one emitting a green emission (G‐gel), and the second emitting a blue emission (B‐gel). The main reason for this difference is that water affects H‐bonding and π–π interactions, further resulting in disparate packing modes of gelators. In addition, only the G‐gel displays gel‐to‐sol transition accompanied with fluorescence switching according to the trans‐cis photoisomerization of cyanostilbene under UV light irradiation. The B‐gel does not exhibit any change because of its tight hexagonal packing arrangement. Such packing modes restricted the space in which molecules were located and inhibited the transformation of configuration of cyanostilbene. These phenomena underline the incomparable status of packing modes and molecular configuration in regulating fluorescence properties and photoresponse behavior in organic solid‐state luminescent materials.

Aggregation‐Induced Emission‐Active Gels: Fabrications, Functions, and Applications

“…The typical AIE‐active LMWGs employed in these studies were summarized according to the type of AIE moiety (i.e., TPE, tetraphenylsilole [TPS], and CNS), as outlined in Figure . More specifically, typical AIE‐active LMWGs based on TPE are 43 and 44 , [ 67 ] 45 , [ 68 ] 46 , [ 69 ] 47 , [ 70 ] 48 , [ 71 ] 49 , [ 72 ] 50 , [ 73 ] 51 , [ 74 ] 52 , [ 75 ] 53 , [ 76 ] 54 , [ 77 ] 55 , [ 78 ] 56 , [ 79 ] 57 , [ 80 ] 58 and 59 , [ 81 ] and 60 , [ 82 ] while typical AIE‐active LMWGs based on TPS are 61 and 62 , [ 83 ] and 63 , [ 62 ] and typical AIE‐active LMWGs based on CNS are 7 , [ 31,35–37 ] 64 , [ 84 ] 65 , [ 85 ] 66 and 67 , [ 86 ] 68 , 69 and 70 , [ 87 ] 71 , 72 and 73 , [ 88 ] 74 , [ 89 ] 75 and 76 , [ 90 ] 77 and 78 , [ 91 ] 79 , [ 92 ] 80 , [ 93 ] 81 , [ 94 ] 82 , [ 95 ] 83 and 84 , [ 96 ] 85 and 86 , [ 97 ] 87 , 88 and 89 , [ 98 ] 90 , [ 99 ] 91 , [ 100 ] 92 , [ 101 ] 93 , [ 102 ] and 94 , 95 and 96 . [ 103 ] Information of the AIE‐active supramolecular gels from the above LMWGs based on TPE, TPS, and CNS is also summarized in Table 2 .…”

Programmable photoresponsive materials based on a single molecule via distinct topochemical reactions

“…Different spatial arrangements not only affect the photomechanical deformation, but also shi the emission color of the materials. The luminescence of cyanostilbene is sensitive to the molecular structure and spatial packing, [45][46][47][48][49] and hence BNAa and BNA-b exhibited unique uorescence changes accompanied by [2 + 2] photodimerization. As shown in Fig.…”

Cyanostilbene‐Based AIEgen Smart Film: Optical Switching by Engineering Molecular Packing Structure and Molecular Conformation Through Thermal and Photoinduced Monotropic Phase Transition

“…After irradiation with 365 nm UV light, new peaks (H a ′, H b ′, and H c ′) corresponding to cis conformer are emerged. [30,31,61] To investigate the changes in transmittance and luminescence of D4CS solid films upon thermal and photoinduced phase transition, an isotropic D4CS liquid is injected into www.advopticalmat.de glass sandwich cells with a cell gap of 10 µm and then cooled to room temperature. D4CS solid films have different transmittance depending on the cooling rate (Figure 3a).…”

“…The conformational change caused by photoisomerization of cyanostilbene leads to changes in molecular energy level and molecular packing structure and morphology, which can have a noticeable positive effect on the desired properties of cyanostilbene‐based materials. [ 27–31 ]…”

“…The conformational change caused by photoisomerization of cyanostilbene leads to changes in molecular energy level and molecular packing structure and morphology, which can have a noticeable positive effect on the desired properties of cyanostilbene-based materials. [27][28][29][30][31] Siloxanes with Si-O-Si linkage have intrinsic features such as hydrophobicity, high flexibility and nanophase separation, which sometimes induces low-ordered, partially ordered molecular self-assembly or monotropic phase transition behavior. For this reason, various siloxane groups are chosen as chemical connectors, end chains and polymer backbones to tune molecular packing structures as well as to program phase transitions.…”