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The potential of azobenzene derivatives that can undergo photoinduced solid-to-liquid transition at room temperature has been demonstrated in many fields such as photo-actuators, energy storage and photo-switchable adhesives. However, both their natural yellowish colour and slow liquid-to-solid phase transition restoration limit their universality in applications. Here, a colourless N-benzylideneaniline derivative molecule with asymmetric side-group substitution (MCN) is synthesized. The small molecular crystal of MCN achieves a reversible photoinduced crystal-to-isotropic liquid transition at room temperature. Due to the short half-life of MCN metastable isomers, the phase transition restoration rate here is significantly faster than that of azobenzene derivatives. As a result, only a single wavelength light source is needed to achieve complete phase change control. The phase transition behaviour of MCN is in situ monitored by using a UV-vis absorption spectrometer in a time-driven mode and a polarizing optical microscope, and its phase transition mechanism is proposed. Furthermore, a smart glass with photo-switchable transmittance is developed by mixing an MCN crystal with a commercial liquid crystal (5CB). [ABSTRACT FROM AUTHOR]

The stimuli-responsive, low molecular weight, dynamically tunable photophysical features have long been an important objective that challenges chemists in synthesizing liquid crystal (LC) compounds. Herein, the effect of core fluorination on the mesomorphic behavior of fan-like azobenzene derivatives was reported. Two new series of azobenzene derivatives which differ from each other in the length of the terminal alkoxy side chain as well as fluorine (-F) group substitution on the azobenzene moiety were synthesized (3a-3c, 4a-4c) and molecular structures of the compounds were confirmed using various analytical techniques. Absorption spectra of the LC compounds 3b and 3c are characterized by ππ∗ transitions around 350–410 nm. The self-assembly of these LC compounds was investigated using polarized optical microscope (POM) and differential scanning colorimetry (DSC). The trans -to- cis photoisomerization of the LC compounds 3b and 3c occurs in these absorption bands. The trans -to- cis photoisomerization of LC compounds 3b and 3c showed 4 h and 24.5 h whereas, thermal cis -to- trans isomerization rates were found to be 90s and 100s resulting in tuning of mesophases. Room temperature photoluminescence (RTPL) of LC compounds 3b and 3c when excited at 220 nm, 230 nm and 240 nm showed several sharp/weak emission intensity bands. Both the LC compounds (3b, 3c) showed sharp blue emission bands and yellow/green/orange colored bands correspond to weak emission spectra when excited at 220 nm. Further, steady state photoluminescence (SSPL) spectra of these both LC compounds revealed sharp near edge emission bands and broad violet emission peaks with higher Stoke's shift as well as full width half maximum (FWHM). Fluorescence lifetime decay (FLD) studies of compound 3 b unveiled an average lifetime (τ) shuttle between 17.24 ns and 103.60 ns at various excitation wavelengths. However, FLD of LC compound 3c unveiled that the τ fluctuates between 27.00 ns and 102.56 ns at various excitation wavelengths. Quantum yield (QY) decreases for both the LC compounds with an increase in excitation wavelengths. The study proved the importance of the alkoxy side chain at one end of the aromatic ring and core fluorination as a significant tool to modify the LC behavior of azobenzene derivatives. Thus, synthesized azobenzene derivatives are potentially useful for developing permanent optical storage and display devices. [Display omitted] • A new series of azobenzene derivatives with terminal alkoxy side chains were synthesized. • Self-assembly and textures of LC compounds 3b and 3c were investigated using POM and DSC. • Photoisomerization times for LC compounds 3b and 3c were found to be 4 h and 24.5 h, respectively, with thermal back relaxation times of 90 s and 100 s. • Emission properties of LC compounds 3b and 3c included sharp and weak intensity peaks under RTPL and multicolor emissions (blue, yellow, green, orange) under SSPL. • LD for LC compounds 3b and 3c ranged between 17.24 ns to 103.60 ns and 27.00 ns to 102.56 ns, respectively, with QY decreasing as excitation wavelengths increased. [ABSTRACT FROM AUTHOR]

Cilia are of vital importance for myriad of natural functions such as the propulsion of microorganisms or the cleaning of the mammalian respiratory system. These cilia often show coupled 3D shape changes, such as waves, to perform their function. Here, we present a versatile platform to fabricate artificial micrometer‐sized azobenzene‐doped liquid crystal polymer cilia by replica molding from a track‐etched polyimide membrane. The cilia are tuneable in their size and show excellent homogeneity and high number densities over large areas. By electrically aligning the liquid crystal monomers in a splay alignment during photopolymerization, the symmetry in most cilia is broken, which allows them to reversibly bend toward a predetermined side when exposed to heat or UV light. When the applied stimulus is carefully controlled, the response can be tuned in speed and magnitude. Addressing both the trans‐ and cis‐isomers of the azobenzene derivative simultaneously makes the cilia oscillate out of plane continuously in a preprogrammed pattern with a frequency and amplitude of choice, without any obvious signs of fatigue. Thanks to the versatility of this cilia platform, a wide range of applications such as transporting loads in confined spaces, self‐cleaning surfaces, haptics, or energy generation is foreseen. [ABSTRACT FROM AUTHOR]

Azobenzene derivatives have become one of the most famous photoresponsive chromophores in the past few decades for their reversible molecular switches upon the irradiation of actinic light. To meet the ever-increasing requirements for applications in materials science, biomedicine, and light-driven devices, it is usually necessary to adjust their photochemical property from the molecular level by changing the substituents on the benzene rings of azobenzene groups. Among the diverse azobenzene derivatives, azopyridine combines the photoresponsive feature of azobenzene groups and the supramolecular function of pyridyl moieties in one molecule. This unique feature provides pH-responsiveness and hydrogen/halogen/coordination binding sites in the same chromophore, paving a new way to prepare multi-functional responsive materials through non-covalent interactions and reversible chemical reactions. This review summarizes the photochemical and photophysical properties of azopyridine derivatives in supramolecular states (e.g., hydrogen/halogen bonding, coordination interactions, and quaternization reactions) and illustrates their applications from photoresponsive liquid crystals to light-driven devices. We hope this review can highlight azopyridine as one more versatile candidate molecule for designing novel photoresponsive materials towards light-driven applications. [ABSTRACT FROM AUTHOR]

Advanced encryption/decryption strategies are of great significance for information protection and data security. It is highly desirable yet quite challenging to develop functional materials for encrypting/decrypting information more effectively. Herein, a novel emissive liquid crystal elastomer (LCE) for multidimensional and multistage encryption is proposed for the first time, through synergistic utilization of phototunable fluorescence and the photoprogrammable shape. The fluorescent LCE is fabricated by incorporating an aggregation‐induced‐emission α‐cyanodiarylethene‐based hydrogen‐bonded complex and azobenzene derivative into the LCE networks through covalent bonding. Because of the photoisomerization of both these two photosensitive derivatives under the same exciting light, the consequent LCE films exhibit photoinduced reversible fluorescence changes and shape deformations that are suitable for data storage and encryption. On this basis, the collaborative usage of photolithography‐based 2D fluorescent images and photoprogramming 3D shape configurations can lead to multidimensional and multistage encryption. Moreover, this encryption strategy is reprogrammable, allowing for repeatable encoding and decrypting. The results demonstrated here reveal that the reversible phototunable fluorescent LCE materials exhibit promising applications in data storage and encryption. [ABSTRACT FROM AUTHOR]

Abstract The photoisomerization and thermal relaxation processes of three amphiphilic azobenzene derivatives (LCA n) showing liquid-crystalline properties were studied in solutions and in monomolecular films formed using Langmuir and Langmuir-Blodgett techniques. The well-controlled isomeric state of LCA n in chloroform during the UV irradiation allowed to prepare spreading solutions containing trans isomers , cis isomers or their mixture and to investigate molecular organization in the Langmuir films made of them. Surface pressure-mean molecular area isotherms and compression modulus-surface pressure dependences delivered information on a thermodynamic state, phase transitions and intermolecular interaction in the monolayers. LCA n in the trans state create densely-packed films, in which the photoisomerization do not occur due to the lack of free volume for the change of the molecules conformation and their strong tendency for the H-type aggregation. However, the reversible switching of the LCA n conformation during cyclic photoisomerization and thermal relaxation processes was observed in the LB films initially deposited onto quartz substrates in the cis state, where molecules are loosely-packed and exist in the monomeric form. Kinetics and rate constants of the photoisomerization and thermal relaxation were determined based on the recorded absorption spectra in order to obtain information on their efficiency and on the impact of the replacement of the alkyl chain attached in the LCA n para position with the alkyloxy chain. Our research show that LCA n are promising materials for application in optical memories, logic gates and holographic gratings. [ABSTRACT FROM AUTHOR]

Abstract: A new class of coil–rod–coil molecules with an azobenzene core was synthesized. They were found to form robust organogels in several organic solvents. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), FTIR spectroscopy, UV/Vis absorption spectroscopy, 1H NMR spectroscopy, and X‐ray diffraction (XRD) revealed that in these organogels, the molecules self‐assembled into a nanofiber network with an H‐type aggregation mode under the joint effect of π–π stacking, intermolecular hydrogen bonding, and van der Waals forces. Interestingly, the incorporation of the azobenzene mesogene into the rigid core led to photoisomerizable liquid crystal materials, which exhibited quick responsiveness to light and temperature, along with the trans–cis transition stimulated by UV light and heating. [ABSTRACT FROM AUTHOR]

The cholesteric polysiloxanes (PLQ series) were obtained by reacting cholesteric monomer and phenolic hydroxyl monomer in different ratios with polysiloxanes. The chiral azo-containing polysiloxanes liquid-crystalline elastomers (LCEs) were synthesised by esterifying PLQ series with acyl acid of azo diacid catalysed by 4-dimethylaminopyridine (DMAP). The chemical structures and mesomorphic properties of monomers and polymers were confirmed by conventional spectroscopic methods. The elastomers displayed elastic properties, reversible phase transition and high thermal stability. The Tg values changed irregularly and Ti values decreased at the beginning and then increased afterwards. The chiral azo-LCEs showed colourful textures and a Grandjean texture could be observed, which exhibited a red shift with increasing content of azo moiety. PLQ2-PLQ6 exhibited selective reflection in the visible light region, but PLZ1-PLZ4 can only observe selective reflection when appropriate mechanical pressure was imposed on the polymers. The PLZ series was carefully investigated by ultra violet-visible spectroscopy. [ABSTRACT FROM AUTHOR]

• Monosubstituted ferrocenomesogens containing azobenzene and 1,2,3-triazole simultaneously were synthesized for the first time. • They display enantiotropic nematic and smectic C mesophase, wide mesophase range and relatively low melting point. • These ferrocenomesogens showed good photoisomerization and electrochemical properties. Monosubstituted ferrocene based azobenzene liquid crystals were synthesized, in which ferrocene was flexibly attached to the mesomorphic core by click reaction. The counterpart compounds without ferrocene unit were also prepared. Two series of compounds displayed liquid crystal behaviours during heating and cooling, and had wide mesophase range. In the process of cooling, the compounds underwent a transformation from nematic phase to smectic C phase. When ferrocene was introduced into the molecule, the melting point of most compounds decreased by 30–40 °C, and the mesophase range was still as wide as 71–97 °C. These compounds emitted fluorescence at 400–550 nm and had strong absorption near 280 nm and 350 nm. Under the irradiation of 365 nm ultraviolet light, these compounds transformed rapidly from E to Z isomers, while the reverse reaction occurred slowly in the dark, especially the molecules containing ferrocene. Cyclic voltammetry studies showed that ferrocene based azobenzene derivatives exhibited one electron transfer processes with low formal redox potentials, indicating that these compounds are easily oxidized. [ABSTRACT FROM AUTHOR]

Abstract: Chiral azobenzenes can be used as photoswitchable dopants to control supramolecular helices in liquid crystals. However, the lack of thermal stability of the cis‐isomer precludes envisioning the generation of long‐lived supramolecular helices with light. Here, this study demonstrates thermally stable and axially chiral azobenzene switches that can be used as chiral dopants to create supramolecular helices from (achiral) nematic liquid crystals. Their trans‐to‐cis photoisomerization leads to a variation of helical twisting power that reaches up to 60%, and the helical superstructure that is engineered with light displays a relaxation time that reaches tens of hours. These results demonstrate that combining ortho‐fluorination with axial chirality in molecular photoswitches constitutes an efficient strategy to promote long‐lived helical states. Further, this approach shows potential to design supramolecular machines that are controlled by light entirely. [ABSTRACT FROM AUTHOR]

This work shows the possibility of fabricating one- and two-dimensional diffraction structures based on liquid crystals photoaligned with the layers of photosensitive azobenzene poly(ester imide). The gratings involve a micron-sized planar-twisted nematic alignment. The diffraction efficiency of these gratings is controlled by a uniform electric field applied across the cell. The electro-optical measurements showed short switching times (0.8 ms and 7 ms for τ r i s e and τ d e c a y respectively) and low driving electric fields ( 1 . 5 V ∕ μ m ) of 1st order diffracted light. The LC grating is regarded as an amplitude grating in the low electric field region and a phase grating in the high electric field region. Moreover the diffraction efficiency is polarization-independent in the wide range of external electric fields. [ABSTRACT FROM AUTHOR]

This study comes to complete the initial investigation of the liquid crystalline properties of 4-[(4-chlorobenzyl)oxy]-3,4′-dichloroazobenzene (CODA). Here, the thermal analysis of CODA dye was performed in air flow and nitrogen flow atmospheres by means of simultaneous thermogravimetry TG, derivative thermogravimetry DTG, differential thermal analysis DTA and differential scanning calorimetry DSC; differences between the two steps of the thermal degradation of CODA related to the two experimental atmospheres were observed. Drops cast and spin coating techniques were used for nanostructuring CODA on platinum (Pt) substrates; the deposited materials were characterised by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Exotic crystalline nanowires of CODA were obtained as function of used deposition technique, while the deposition time decisively influenced their features. The present results advocate for employing these materials as template matrices for producing high-aspect-ratio inorganic nanomaterials (i.e. Au) in the form of nanotubes, nanowires, nanorods or nanoparticles with enhanced functional properties. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We demonstrate an optically switchable half-wave plate (HWP) composed of a photoaligned and axially symmetric liquid crystal (ASLC) film containing two azobenzene derivatives, methyl red (MR) and 4-butyl-4′-methoxyazobenzene (BMAB). MR is responsible for photoalignment, and BMAB is used for optical tuning and switching the state of polarization (SOP) of probe beam (633 nm He–Ne laser) passing through the MR/BMAB doped ASLC film. The photoaligned ASLC film is first fabricated using a line-shaped laser beam (532 nm) exposure applied on a rotating LC sample. The fabricated ASLC film can passively change the linearly polarized light. Under UV light exposure, the formation of cis -BMAB (bend-like shape) within the film disrupts the LC molecules, switches the LC orientation, and further changes the SOP of the probe beam. Under laser irradiation (532 nm), the formation of trans -BMAB (rod-like shape) reverts the LC orientation back and simultaneously generates cis -MR, helping anchor the LC in the previously photoaligned orientation. The photoaligned MR/BMAB-doped LC HWP can change the linear SOP under alternating UV and visible light exposure. [ABSTRACT FROM AUTHOR]

Molecular mobility in liquid crystalline (LC) side-chain polyacrylates and polymethacrylates with cyanoazobenzene side mesogens and methylene spacers of different lengths was investigated by dielectric spectroscopy and thermally stimulated depolarization currents methods. For both series of LC polymers, near glass transition temperature (Tg), two relaxations of cooperative character related to segmental motion (α process) and reorientation of mesogens around their short axis (δ process) are observed. Cooperativity of these processes decreases with increasing length of side chains being higher for the α process. Good correlation between dielectric spectroscopy and thermally stimulated depolarization currents methods is obtained for the temperature transitions of the α and δ processes. [ABSTRACT FROM PUBLISHER]

Twelve novel homologues having azolinkage of the series 4-Carbethoxy-[3′chloro-4′(4″-n-alkoxy benzoyloxy)] azobenzenes has been synthesized. The methyl ton-hexyl homologues exhibit only a nematic mesophase, while then-heptyl ton-dodecyl homologues exhibit both smectic and nematic mesophases. Then-tetradecyl andn-hexadecyl homologues exhibit only smectic mesophases. The plot of transition temperatures versus number of carbon atoms in alkoxy chain exhibits an odd-even effect for the nematic-isotropic transition temperatures. The mesogenic behavior of present series is explained by comparing its homologue with other homologue of related mesogenic series. The synthesized compounds were characterized by combination of elemental analysis and standard spectroscopic methods. For the exhibition of mesomorphic property the role of ester and azo linkages has been discussed. The impact of lateral chloro group on mesomorphism is also discussed. [ABSTRACT FROM PUBLISHER]

Two new groups of azobenzene ester derivatives were synthesised: alkyl 4-[4-(nonyloxy)phenyl]diazenyl]benzoates and 4-[4-(nonyloxy)phenyl]diazenyl]phenyl alkanoates. All 35 presented homologues are mesogenic. Moreover, some of the above-mentioned compounds exhibit rich liquid-crystalline polymorphism likewise tetramorphism. During this investigation by the use of polarising optical microscopy, differential scanning calorimetry and X-Ray studies, six types of mesophases were detected: nematic, smectics (A, C, I, F) and G. Furthermore, due to the presence of the photosensitive azo moiety, the E–Z isomerisation reaction is possible. This process, which is initiated by the UV irradiation, causes significant changes in the UV-Vis absorption spectra of investigated compounds. However, the photoisomerisation is a reversible process and in the dark the thermal relaxation of Z isomer takes place. Based on the achieved data, the kinetic constants of the isomerisation and relaxation processes were calculated. It shows that conversion of the ester bond makes some changes in the optical properties. The shift of about 7 nm of the absorbance maximum was observed. Surprisingly, the inversion of the ester group has significant influence on the liquid-crystalline polymorphism replacing one mesophase (for benzoates) into four (for alkanoates). [ABSTRACT FROM PUBLISHER]

Photoresponsive materials (PRMs) have long been a hot topic and photo-modulated smart surface is very appealing. Particularly, liquid crystalline PRMs are able to amplify and stabilize photoinduced orientation thanks to their self-assembling and ordering characteristics. Herein, the first pillararene-based azobenzene liquid crystalline PRM with well-defined structure is presented, which can avoid the usually ill-defined composition drawback of polymer PRMs and prevent the severe H-aggregation from suppressing or even completely blocking photoresponse in simple azobenzene derivatives. The pillar[5]arene-based macrocyclic azobenzenes with variant length spacers show wide temperature range smectic liquid crystalline mesophases and excellent film-formation property. The tubular pillar[5]arene macrocyclic framework provides sufficient free volume for azobenzene moieties to achieve reversible photoisomerization and photoalignment; thus, their thin films demonstrate excellent light-triggered modulation of surface free energy, wettability, and even photoalignment-mediated orientation of an upper layer discotic liquid crystal columnar mesophase. Such pillararene-based azobenzene liquid crystals represent novel and promising PRMs with extensive fascinating applications. [ABSTRACT FROM AUTHOR]

A new series of liquid crystals whose molecular structure consists of a U-shaped unit as a central core and two rod-like azobenzenes as the peripheral units are synthesized. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. The existence of nematic and smectic A phase was confirmed by textures and X-ray diffraction. The trans -form of azo compounds showed a strong band in the UV region at ~ 365 nm for the π–π* transition, and a weak band in the visible region at ~ 450 nm due to the n–π* transition. These molecules exhibit a strong photoisomerization behavior in which trans–cis take 50 and 55 s for compounds L4/5 and L4/6, respectively, whereas cis–trans take place almost 29 and 30 h, respectively. Long thermal back relaxation allows us to realize that optical storage devices with these materials which need longer periods. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pattern of liquid crystal droplets dispersed in isotropic liquid is being formed. [•] Formation of the pattern is reversible and pattern diffracts light into orders. [•] Such grating can be recorded in certain temperature and light intensity range. [•] Photothermal and orientational effects are assumed as responsible for the effect. [ABSTRACT FROM AUTHOR]

We present results of fast switching of birefringence changes and diffraction grating recording in a photochromic liquid crystalline molecules, showing liquid-crystalline nematic state close to the room temperature. Dynamic birefringence switching is done in Optical Kerr Effect setup and holographic recording of phase-type gratings is performed in a Degenerate Two Waves Mixing setup. For the induction of refractive index changes in the material in both setups the pulsed lasers are used. We study the dynamics of birefringence changes of the material after excitation, occurring in the range of micro- and milliseconds. [ABSTRACT FROM AUTHOR]

Photosensitive trisazobenzene-based layers, after irradiation with polarized light, are employed to align the common liquid-crystal (LC) compound 4-cyano-4′-heptylbiphenyl (7CB) into predetermined patterns. Surface analysis of the trisazobenzene films indicate that ordering of the LC material is not caused by illumination-induced surface relief structures, but through “molecular mesoepitaxial” phenomena. This finding can be exploited to produce in one-step in-plane patterns of randomly oriented and ordered macroscopic LC domains by irradiation of the substrates. [ABSTRACT FROM AUTHOR]

• Three series of BCLCs were studied for photoswitching. • The effect of linking groups on azodyes was responsible for this effect. • Resorcinol with benzoate ester showed the slowest thermal back relaxation. • Potential materials for optical storage device. • Exhibiting strong structure–property relationship. In this paper, we report on the photoisomerization process of three series of photosensitive bent-core liquid crystals with a lateral chlorine atom in the central resorcinol core and various linkers. The effect of linkers, such as benzoate ester, biphenyl, cinnamate, Schiff base and stilbene on the photoisomerization and thermal back relaxation have been studied using UV–Vis spectroscopy. Resorcinol with benzoate ester showed the longest thermal back relaxation of 7 h, whereas, the bent-cores with the stilbene linker rendered the shortest relaxation time of 4 h. The compiled results suggest the influence of linkers, central resorcinol core and position of the azobenzene moiety on the photoisomerization. Additionally, optical storage device fabricated using cinnamate containing bent-core LC (A3), showed the visibility of bright and dark regions in a crossed polarizers upon illumination at λ = 365 nm, indicating the changes from the ordered to disordered state. The observed properties of constructed device demonstrate the potential application of reported azobenzene derivatives in optical storage devices. [ABSTRACT FROM AUTHOR]

• "T-type" azopolyimides with azopyridine or azobenzene moieties were characterized. • Polyimides with azo groups exhibited large modulations of SRGs up to 330 nm. • Cis-trans isomerization was more stable for polyimides with azobenzene groups. • Azopolyimide exhibited good orienting properties of liquid crystal mixture. In this work series of "T-type" polyimides with azobenzene or azopyridine moieties were investigated. It is the first report where the "T-type" polyimides with derivatives of azopyridine were investigated. The cis - trans isomerization in the dark in the solid-state was showed. Polyimides with azobenzene derivatives exhibited higher stability of cis - trans recovery than their azobenzene analogues. For the inscription of the surface relief gratings, two different intensities of light (10 and 45 mJ/cm2) and a number of pulses (10 and 100) were used. Polyimides showed the modulation of SRGs up to almost 330 nm. Our studies showed, that azopolyimides are able to orient the nematic liquid crystal molecules in cell-based on effect at the twisted nematic. The obtained maximum value of t ON was 0.9 ms (1 kHz, 1. 5 V/μm) for polyimide with azobenzene moieties. Azopolyimides may be successfully used in many photonic devices based on the alignment of the liquid crystal mixture i.e. LC diffraction gratings, Fresnel lens, Vortex, in a photo-pattering technology for creating radical and azimuthal orienting layers. [ABSTRACT FROM AUTHOR]

C18H18N2O4, monoclinic, P21/n (no. 14), a=5.2291(2) Å, b=10.5932(4) Å, c=15.3775(6) Å, β=96.619(2)°, V =846.13(6) Å3, Z =4, Rgt(F)=0.0479, wRref(F2)=0.1438, T =293(2) K. [ABSTRACT FROM AUTHOR]

C18H18N2O4, monoclinic, P21/n (no. 14), a=5.2291(2) Å, b=10.5932(4) Å, c=15.3775(6) Å, β=96.619(2)°, V =846.13(6) Å3, Z =4, Rgt(F)=0.0479, wRref(F2)=0.1438, T =293(2) K. [ABSTRACT FROM AUTHOR]

Information about the Polish Liquid Crystal Society (PLCS) meeting held in Wroclaw in June 2014 is presented. Professor Agnieszka Iwan discusses the use of liquid crystals in organic photovoltaics. Professor Stanislaw Bartkiewicz delivers lecture on liquid crystal systems' photorefraction. Izabela Niezgoda demonstrates the ester group inversion influence on azobenzene derivative liquid crystalline polymorphism.