Photoisomerizable azobenzene star-shaped liquid crystals: bypassing the absence of hydrogen bonding

Abstract

Liquid crystals (LCs) containing azo group are often used in the construction of molecular systems that present both mesomorphic features and reversible photoisomerization. The interest in the search for new...

Thiacalixarene Appended Azo‐based Supramolecular Systems: Self‐assembly and Photo Tuning Reversible Liquid Crystalline Properties

“…Azo based materials with liquid crystalline nature are a significant class and a hot topic since they are reported as a photo responsive materials [16–18] . Due to the photoswitching properties of azo materials, a large number of research groups have worked on to synthesized azo based various shaped liquid crystalline materials with good photophysical properties [19–25] . In the literature survey, very few reports published on supramolecular materials based on azo linker bearing columnar liquid crystalline properties [26–28] .…”

“…[16][17][18] Due to the photoswitching properties of azo materials, a large number of research groups have worked on to synthesized azo based various shaped liquid crystalline materials with good photophysical properties. [19][20][21][22][23][24][25] In the literature survey, very few reports published on supramolecular materials based on azo linker bearing columnar liquid crystalline properties. [26][27][28] Calixarene is a well-known macrocycle having significant active blocks with well-organized molecular shape which make them more specific towards the host-guest recognition properties.…”

A Synthetic Approach for Oxadiazole‐Decorated Azobenzene Photoswitches

“…During the course of our work, the idea to combine properties of oxadiazole core with a switching unit, like azo group, seemed promising to achieve light‐emissive switching molecules. A literature survey regarding similar compounds indicated a few examples of oxadiazole‐azobenzene decorated compounds as fluorescent chemosensors for metal‐ions or building block able to self‐assembly [21–24] . Therefore, we designed azobenzene 1 decorated with oxadiazole moieties, assuming that: i) the luminescence of the oxadiazole core could be modulated by the switching unit, and ii) the oxadiazole core could act as an electron withdrawing group, enabling a good behaviour of a photoswitch.…”

“…A literature survey regarding similar compounds indicated a few examples of oxadiazole-azobenzene decorated compounds as fluorescent chemosensors for metal-ions or building block able to selfassembly. [21][22][23][24] Therefore, we designed azobenzene 1 decorated with oxadiazole moieties, assuming that: i) the luminescence of the oxadiazole core could be modulated by the switching unit, and ii) the oxadiazole core could act as an electron withdrawing group, enabling a good behaviour of a photoswitch. Thus, we report herein synthesis of compounds 1 a-d (Figure 1), their structural characterization, and behavior under light irradiation, in terms of luminescent properties and switching abilities.…”

Method of Molecular Parameters for Columnar Mesomorphism Prediction of Tristriazolotriazines

“…В последние годы более активно исследуются мезогенные гетероциклические структуры с дефицитом электронов и фотолюминесценцией, такие как триазины, тристриазолотриазины, оксадиазолы, пиримидины и др. [13][14][15]. Их особенностями являются самосборка в мезофазе в колончатые структуры (самоорганизация), что обеспечивает возможность одномерного переноса заряда за счет перекрывания ароматических π-орбиталей («π-стекинг») [16][17][18], усиление флуоресценции в тонких пленках, вызванное агрегацией [19,20], способность проявлять свойства молекулярных роторов [21,22].…”