Mesomorphism, polymerization, and chirality induction in α -cyanostilbene-functionalized diacetylene-assembled films: Photo-triggered Z /E isomerization

Abstract

Engineering of molecular stacking arrangement via environmental stimuli is of particular interest in stimuliresponsive self-assembling architectures. A novel dual photofunctionalized diacetylene ((Z)-CNBE-DA) molecule was synthesized, in which photo-responsive cyanostilbene moieties exhibited interesting Z-E isomerization upon UV light irradiation and could be utilized to modulate mesomorphism, molecular stacking arrangement and their resulting polymerization behavior. Rod-like (Z)-CNBE-DA could self-assemble into well-defined lamellar structures and the helical polydiacetylene (PDA) chains could be formed upon irradiation with circularly polarized ultraviolet light (CPUL). However, the bent-shaped (E)-CNBE-DA molecules only self-assembled into irregular loose packing, inhibiting the formation of ordered helical PDA chains upon CPUL irradiation. In this work, we established the links between chemical structures, molecular packing engineering and photophysical properties, which would be of great fundamental value for the rational design of smart soft materials.

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

“…The enhanced emission could be attributed to the poor solubility of BTTPA in water compared with that in DMSO, indicating that BTTPA exhibited typical AIEE characteristics. In terms of UV/Vis absorption, an absorption peak at 347 nm was observed in pure DMSO, which was attributed to π–π* transition absorption of the cyanostilbene moieties . Along with the increase in water content, a wider peak as well as leveled‐off tails in the visible region were observed and the intensity of the main peak had a distinct decrease, revealing that BTTPA definitely forms aggregates in the poor solvent of water (Figure b) .…”

“…In terms of UV/Vis absorption, an absorption peak at 347 nm was observed in pure DMSO, which was attributedt o p-p*t ransition absorption of the cyanostilbene moieties. [14] Along with the increase in water content,awider peak as well as leveled-off tails in the visible regionw ereo bserveda nd the intensity of the main peak had ad istinct decrease, revealing that BTTPAd efinitely forms aggregatesi nt he poor solvent of water ( Figure 3b). [15] The results offer furthers upport for the AIEE characteristics of BTTPA.…”

Homochiral Supramolecular Thin Film from Self-Assembly of Achiral Triarylamine Molecules by Circularly Polarized Light

“…The spontaneous symmetry breaking of self-assembled structures based on achiral molecules can be achieved by purely physical fields, such as circularly polarized light (CPL) irradiation [8][9][10][11][12][13][14][15][16], hydrodynamic shear force by stirring [6,7,17,18] or the combination of light, magnetic, hydrodynamic or 2 of 13 thermal stimuli [19,20]. Among them, CPL is considered to be a true chiral entity and has been regarded as the origin of homochirality in nature [21,22].…”

“…Light-initiated self-assembly systems have also been employed for supramolecular chirality by using CPL to initiate and facilitate the stacking of building blocks through conformational change, and to simultaneously control the handedness of self-assembled structures [11][12][13]. In addition, the formation of chiral structures can be achieved from achiral one-dimensional supramolecular assemblies through a helical polymerization that induces the rotational direction [14][15][16]. However, generation of supramolecular chirality by irradiation of CPL is restricted to the case that light affects monomers, causing the change of properties, and the investigation of the pure effect of CPL as a chiral source at the generation of supramolecular chirality is hindered.…”

Mesomorphic Sugar‐Coated Polydiacetylene Polymers

“…[1][2][3][4] PDA polymers exhibit characteristic thermochromatic properties, as a result these polymers are utilized in a number of biological, interfacial, and materials applications. [4][5][6][7][8][9][10][11][12][13][14][15] Inducing anisotropy in PDAs would result in a liquid crystalline (LC) behavior, [16][17][18] as illustrated through functionalizing the polymers with moieties such as aromatic dicarboxylic acids, [13,18,19] biphenyl esters, [20,21] cyanostilbene, [22] and azobenzene. [23] Incorporation of amphiphilicity in a molecule is a fruitful route to enable mesomorphic behavior.…”