Synthesis and liquid crystalline behaviour of substituted (E)-phenyl-4-(phenyldiazenyl) benzoate derivatives and their photo switching ability

Azobenzene derivatives containing phenyl/4-halogen-phenyl 4-{(E)-[4-(pent-4-en-1-yloxy)phenyl]diazenyl}benzoate group with different electronegative substituent (H, F, Cl, Br and I) at other end was synthesised. These azo-based benzoate derivatives have been characterised by FTIR, 1H-NMR, 13C-NMR, elemental analyser, POM and UV-Vis spectroscopy. Photosaturation at 358 nm obtained after 82 s of UV irradiation and the longest thermal back relaxation time of 45 h recorded by UV-Vis. The azo derivative could be possible photolock under UV light, as observed by the improved thermal back relaxation time. The resulting photolockable chain of azobenzene might prove valuable in the development of optical device application. These azobenzene moieties also exhibit liquid crystalline behaviour with respect to the halogen substitution as an electron withdrawing group shows that strong structure property relationship exists among them

Synthesis and liquid crystalline behaviour of substituted (E)-phenyl-4-(phenyldiazenyl) benzoate derivatives and their photo switching ability

Azobenzene derivatives containing phenyl/4-halogen-phenyl 4-{(E)-[4-(pent-4-en-1-yloxy)phenyl] diazenyl}benzoate group with different electronegative substituent (H, F, Cl, Br and I) at other end was synthesised. These azo-based benzoate derivatives have been characterised by FTIR, 1H-NMR, 13C-NMR, elemental analyser, POM and UV-Vis spectroscopy. Photosaturation at 358 nm obtained after 82 s of UV irradiation and the longest thermal back relaxation time of 45 h recorded by UVVis. The azo derivative could be possible photolock under UV light, as observed by the improved thermal back relaxation time. The resulting photolockable chain of azobenzene might prove valuable in the development of optical device application. These azobenzene moieties also exhibit liquid crystalline behaviour with respect to the halogen substitution as an electron withdrawing group shows that strong structure property relationship exists among them

Evaluation of Photoswitching Properties for Hockey Stick-Shaped Mesogens Bearing Azo Benzene Moieties

In this paper, we report the photoresponsive behavior of hockey stick-shaped mesogens bearing azo wing with different terminal alkoxy chains at one terminal end. Except for the compound E16, which exhibits SmC along with nematic phase, all other mentioned compounds exhibit nematic phase alone. Influence of chain length on the photophysical properties were investigated using UV-Vis spectroscopy. It is observed here that influence of chain length is negligible on thermal back relaxation time. Spectroscopic investigation with variable intensities of UV light studies reveals that reverse cis-trans isomerization process was inversely proportional to the intensity of illuminated light. The present study also reveals that the structure-property relationship plays a dominant role on shape anisotropic structures. A spectroscopic study of the solid sample using guest-host mixture was also carried out and the compilation of results forecast these mesogens as ideal candidates for optical storage devices

Luminous and fluorescent cyanobiphenyls exhibiting super-cooled nematic phases

A new series of liquid crystal dimers, 4-cyano-1,3-phenylene bis(4-((4’-cyano-[1,1’−biphenyl]-n-yl)oxy)alkanoate), has been synthesised and confirmed for their molecular structure using standard spectroscopic techniques. Thermal behaviour is assessed using optical polarising microscope (OPM), differential scanning calorimetry (DSC), and X-ray diffraction. Interestingly, all the dimers exhibit a super-cooled nematic phase without crystallisation during cooling cycles. These molecules self-assemble with head-on aggregation assessed by UV–Visible absorption spectra, and they also have a distinct fluorescence characteristic. A super-cooled nematogens self-assemble into head-on aggregation with a fluorescence property. Moreover, the materials were studied for their fluorescence properties and proved to be fluorescence active, making them excellent candidates to be used in designing photo-responsive optical sensor devices.</p

Supramolecular Self-Assembly Properties of Metallo-Ionic Phthalocyanines Constituting Regioisomers

We describe the synthesis and properties of metallo-ionic phthalocyanines (MIPCs), obtained upon interacting metalled phthalocyaninetetracarboxylic acid with 1-ethyl-3-methyl imidazolium chloride in a methanolic sodium hydroxide (NaOH) condition. Two MIPCs analyzed by 1H-NMR and MALDI-TOF, additionally, the four positional regioisomers (Cs, C4h, D2hand C2v) confirm by High Performance Liquid Chromatography (HPLC) analysis indicate the purity of the sample. The UV-visible and photoluminescence spectroscopy used to characterize the effects of peripheral substituents on the absorption and emission spectroscopy that featured the distinctive J(Jelly) and H(hypsochromic) aggregates of MIPCs in a polar solvent. Electrochemical characteristics evaluated through cyclic voltammetry (CV) confirms the redox properties and the electron transfer mechanism studied by DFT calculations. Gelation experiment demonstrated on zinc-ionic phthalocyanine shows the entangled network as evaluated using Scanning Electron Microscopy (SEM) images. We also studied the chromonic liquid crystalline behavior of MIPCs

Synthesis and liquid crystalline behaviour of substituted (E)-phenyl-4-(phenyldiazenyl) benzoate derivatives and their photo switching ability

Azobenzene derivatives containing phenyl/4-halogen-phenyl 4-{(E)-[4-(pent-4-en-1-yloxy)phenyl] diazenyl}benzoate group with different electronegative substituent (H, F, Cl, Br and I) at other end was synthesised. These azo-based benzoate derivatives have been characterised by FTIR, 1H-NMR, 13C-NMR, elemental analyser, POM and UV-Vis spectroscopy. Photosaturation at 358 nm obtained after 82 s of UV irradiation and the longest thermal back relaxation time of 45 h recorded by UVVis. The azo derivative could be possible photolock under UV light, as observed by the improved thermal back relaxation time. The resulting photolockable chain of azobenzene might prove valuable in the development of optical device application. These azobenzene moieties also exhibit liquid crystalline behaviour with respect to the halogen substitution as an electron withdrawing group shows that strong structure property relationship exists among them