4105-89-9Relevant academic research and scientific papers
Thermotropic Liquid-Crystalline and Light-Emitting Properties of Bis(4-aalkoxyphenyl) Viologen Bis(triflimide) Salts
Agra-Kooijman, De?a M.,Al-Karawi, Muhammed Kareem M.,Bhowmik, Pradip K.,Chang, Anthony,Chen, Si L.,Cortez, Raymond G.,Dizon, Erenz J.,Fisch, Michael R.,Gutierrez, Bryan,Han, Haesook,Ho, Andy,Killarney, Shane T.,Kim, Jongin,Kumar, Satyendra,Mandal, Hari D.,Mendez, Klarissa,Principe, Ronald Carlo G.,Sharpnack, Lewis
, (2020/05/29)
A series of bis(4-alkoxyphenyl) viologen bis(triflimide) salts with alkoxy chains of different lengths were synthesized by the metathesis reaction of respective bis(4-alkoxyphenyl) viologen dichloride salts, which were in turn prepared from the reaction of Zincke salt with the corresponding 4-n-alkoxyanilines, with lithium triflimide in methanol. Their chemical structures were characterized by 1H and 13C nuclear magnetic resonance spectra and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by differential scanning calorimetry, polarizing optical microscopy, and variable temperature X-ray diffraction. Salts with short length alkoxy chains had crystal-to-liquid transitions. Salts of intermediate length alkoxy chains showed both crystal-to-smectic A (SmA) transitions, Tms, and SmA-to-isotropic transitions, Tis. Those with longer length of alkoxy chains had relatively low Tms at which they formed the SmA phases that persisted up to the decomposition at high temperatures. As expected, all of them had excellent thermal stabilities in the temperature range of 330-370 ?C. Their light-emitting properties in methanol were also included.
Synthesis and mesomorphic properties of novel Schiff base liquid crystalline EDOT derivatives
Gowda, Ashwathanarayana,Roy, Arun,Kumar, Sandeep
, p. 840 - 847 (2016/12/30)
Herein, we reported novel banana liquid crystals derived from ethylenedioxythiophene (EDOT) central unit encompass with Schiff base. Structural charecterization of these compounds was carried out from their spectral and elemental analysis. Physical properties of all the newly synthesized compounds were investigated by polarising optical microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and Raman spectroscopy. EDOT bearing three-ring Schiff base bent-core compounds are non-mesomorphic but all the Schiff bases containing five-rings exhibit enantiotropic mesophase behaviour. The higher homologues show long range nematic phase along with a smectic C phase at lower temperature. While the lower homologues exhibit only N phase. The bent-angle in these compounds is in between of calamitic LCs and banana LCs; therefore, the molecules escape from the polar order packing observed in typical bent core LCs. Detailed XRD investigation endorses the presence of the N phase in lower homologues and Sm C phase in higher homologues.
H-Shape mesogenic dimers-the spacer parity effect
Wolska,Kolpaczynska,Mieczkowski,Pociecha,Gorecka
, p. 20354 - 20359 (2017/04/19)
It was found that for H-shape dimers, the parity of the number of atoms in the spacer linking the mesogenic cores has important influence on the mesogenic properties only for the molecules with weak mesogenic core anisotropy. In the case of stronger core
Rod shaped oxovanadium(IV) Schiff base complexes: Synthesis, mesomorphism and influence of flexible alkoxy chain lengths
Gupta, Bishop Dev,Datta, Chitraniva,Das, Gobinda,Bhattacharjee, Chira R.
, p. 177 - 183 (2014/05/06)
A series of oxovanadium(IV) complexes of bidentate [N,O] donor Schiff-base ligands of the type [VO(L)2], [L = N-(4-n-alkoxysalicylaldimine)- 4′-octadecyloxyaniline, n = 8, 10, 12, 14, 16 and 18] have been synthesized. The compounds were characterized by elemental analyses, Fourier transform infrared spectroscopy (FTIR), 1H, 13C nuclear magnetic resonance (NMR), ultraviolet-visible spectroscopy (UV-Vis), and fast atom bombardment (FAB) mass spectrometry. The mesomorphic behavior of the compounds was studied by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The ligands and complexes are all thermally stable exhibiting smectic mesomorphism. The ligands 8-OR to16-OR show SmC phase at ～113-118 °C and an unidentified SmX phase reminiscent of soft crystal at ～77-91°C whereas the complexes all showed SmA phases. Interestingly the complexes with C10 and C12 alkoxy chain length exhibited additionally SmC phases also. The melting points of the ligands linearly increases whereas mesophase to isotropic transition temperature decreases as a function of increasing carbon chain length of alkoxy arm while no trend was apparently noticeable for the complexes.
Phototunable liquid-crystalline phases made of nanoparticles
Zep, Anna,Wojcik, Michal M.,Lewandowski, Wiktor,Sitkowska, Kaja,Prominski, Aleksander,Mieczkowski, Joef,Pociecha, Damian,Gorecka, Ewa
supporting information, p. 13725 - 13728 (2015/04/16)
The properties of liquid-crystalline (LC) hybrid systems made of inorganic nanoparticles grafted with photosensitive azo compounds are presented. For materials with a large density of azo ligands at the surface, the LC structure can be reversibly melted by UV light, and the return to the LC state does not require the absorption of visible light. For systems with a lower density of azo ligands, UV light causes shortening of the distance between metal sublayers in the lamellar phase. Interestingly, the azo derivatives attached to the nanoparticle surface show very different kinetics of cis/trans conformational change as compared to the free molecules. The cis form of free ligands in solution is stable for days, whereas the isomerization of molecules attached to the nanoparticle surface to the trans form takes only a few minutes. Apparently, owing to the crowded environment, azo ligands immobilized at a metal surface behave as they would in the condensed state.
Designer ionic liquid crystals based on congruently shaped guanidinium sulfonates
Butschies, Martin,Frey, Wolfgang,Laschat, Sabine
supporting information; experimental part, p. 3014 - 3022 (2012/04/10)
Ionic liquid crystals are mesogenic compounds that consist of cations and anions, usually rod-like cations and spherical anions. Herein we report a new method for the synthesis of ionic liquid crystals by using cations and anions of the same molecular shape with oppositely charged head groups. Thus, 4-alkoxyphenylpentamethylguanidinium 4-alkoxyphenylsulfonate ion pairs have been synthesised. 4-Alkoxyphenylpentamethylguanidinium iodides were also prepared to determine the influence of congruently shaped anions, in comparison with their spherical counterparts, on mesophase behaviour, which was investigated by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction (XRD). All the liquid crystalline salts exhibit smectic A mesophases with strongly interdigitated bilayer structures. The guanidinium sulfonate ion pairs show mesomorphic properties from shorter alkyl chain lengths (≥C9) and lower melting points (≈10 K), whereas the corresponding guanidinium iodides are liquid crystalline for longer alkyl chain lengths (≥C14). For chains with ≥C18, however, the mesophase range decreases for the sulfonate ion pairs, but not for the iodide salts. Tuning mesophase stability: Guanidinium sulfonate ion pairs with congruently shaped anions and cations with short alkyl chains R (see scheme) have favourable mesogenic properties with respect to mesophase stability in comparison with their guanidinium counterparts with spherical iodide anions. Copyright
Studies of calamitic liquid crystalline compounds involving ester-azo central linkages with a biphenyl moiety
Thaker,Dhimmar,Patel,Solanki,Patel,Chothani,Kanojiya
experimental part, p. 172 - 191 (2012/07/27)
Two mesogenic homologous series involving ester-azo central linkages with a biphenyl moiety have been synthesized, such as 4'-[(4-n-alkoxyphenyl)diazenyl] biphenyl-4-ol (series I) and 4'-[(4-n-alkoxyphenyl) diazenyl]-4-butoxy phenyl biphenyl-4-carboxylate (series II). Azobiphenyl of series I having a free hydroxyl group with strong hydrogen bonding exhibits a high-temperature enantiotropic smectic phase. Whereas in series II, compounds containing C 1-C8 carbon atoms exhibit only a monotropic smectic phase and compounds with C10, C12, C14, and C 16 atoms show an enantiotropic smectic phase. These compounds were characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectral studies. The phase transition and mesogenicity of these substances were studied by polarizing optical microscopic and differential scanning calorimetric techniques. Their thermal stabilities and other characteristics are discussed. Copyright Taylor &Francis Group, LLC.
Modulating the self-assembly of rigid "clicked" dendrimers at the solid-liquid interface by tuning non-covalent interactions between side groups
Cadeddu, Andrea,Ciesielski, Artur,El Malah, Tamer,Hecht, Stefan,Samori, Paolo
supporting information; experimental part, p. 10578 - 10580 (2011/11/06)
First generation poly(triazole-phenylene) dendrimers equipped with peripheral alkyl or carboxylic acid groups to engage in van der Waals and hydrogen-bonding interactions, respectively, assemble into distinct two-dimensional nano-structures at the solid-l
Role of terminal heterocyclic ring on mesomorphic properties of homologous series
Thaker,Patel,Solanki,Dhimmer,Dave
experimental part, p. 63 - 80 (2010/09/05)
Two new homologous series of compounds with a heterocyclic ring having sulfur and oxygen as a hetero atom derived from p-hydroxy acetophenone and alkoxy aniline containing cinnamate-azomethine as central linkages have been synthesized. viz. 4(furalacryloxy) α-methyl benzylidine-4′-alkoxy aniline and 4(thianylacryloxy) α-methyl benzylidine-4′-alkoxy aniline. The compound of both the series have been characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectrometry method. Their liquid crystalline properties have been investigated by optical polarizing microscopy and differential scanning calorimetry (DSC) studies. All the derivatives are mesomorphic in nature showing the nemetic phase. The mesomorphic properties of the present two series are compared with other structurally related series to evaluate the effect of thiophene and furan on mesomorphism. Copyright Taylor & Francis Group, LLC.
Hydrogen bonded supramolecular liquid crystalline complex of 2,4,6-triarylamino-1,3,5-triazines with semiperfluorinated benzoic acids
Cheng, Xiaohong,Jin, Jie,Li, Quan,Dong, Xing
experimental part, p. 1957 - 1962 (2011/06/19)
Hydrogen bonded supramolecular complexes of 2,4,6-triarylamino-1,3,5-triazines (Tn) with semiperfluorinated benzoic acids have been prepared. The mesophase behaviors of such complexes were investigated with POM (polarized optical microscopy), DSC (differe
