- Multistability at Room Temperature in a Bent-Shaped Spin-Crossover Complex Decorated with Long Alkyl Chains
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An iron(II) pyridyl-benzohydrazonate-based complex decorated with long alkyl chains is reported as a rare spin-crossover compound displaying a wide thermal hysteresis spanning room temperature. On heating, this compound exhibits a spin transition between
- Rosario-Amorin, Daniel,Dechambenoit, Pierre,Bentaleb, Ahmed,Rouzières, Mathieu,Mathonière, Corine,Clérac, Rodolphe
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Read Online
- Aggregation-induced emissions in the mesogenic BF2complexes of aroylhydrazines
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Herein, we report the synthesis of two new families of borondifluoride complexes derived from aroylhydrazines and the investigation of their mesomorphic and AIE properties. The crystallographic structure of the mesogenic complex1a-BF2(n= 8) was
- Cai, Yi-Hong,Chih, Hsin-Yun,Lai, Chung K.,Lee, Gene-Hsiang
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p. 12557 - 12568
(2021/07/25)
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- Nonsymmetrical cholesterol dimers constituting regioisomeric oxadiazole and thiadiazole cores: an investigation of the structure-property correlation
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Three series of chiral nonsymmetrical dimers were prepared by connecting promesogenic cholesterol to a bent structure derived from a substituted 1,3,4-oxadiazole or 1,2,4-oxadiazole or 1,3,4-thiadiazole moiety. These two mesogenic segments are interconnected through spacers of varying lengths and parity. The structures of the bent achiral unit were systematically varied with different central heterocyclic cores to understand the influence of bent angles on the thermal and gelation behavior. The bent angle of the achiral unit, which is determined by the heterocyclic core, has a major role in the stabilization of frustrated phases. Dimers based on the 1,3,4-oxadiazole unit with a more bent structure stabilized frustrated phases like blue phases and twist grain boundary phases. The bent system with a wider bent angle preferred to stabilize chiral nematic and smectic A phases. It is interesting to note that an increased bent structure reduced the mesophase stability as in the case of dimers based on the 1,3,4-oxadiazole unit, where many compounds exhibited monotropic phases. In the case of dimers with a wider bent angle, enantiotropic mesomorphism was observed. All the compounds showed blue light emission in the solution. Among these chiral dimers, only the compounds based on the 1,3,4-oxadiazole unit showed the gelation ability, which emphasizes how small structural changes like bent angle, dipole moment and the type of heteroatom in the heterocyclic unit affect the macroscopic self-assembly.
- Pradhan, Balaram,Chakraborty, Nirmalangshu,Gupta, Ravindra Kumar,Shanker,Achalkumar, Ammathnadu S.
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supporting information
p. 879 - 888
(2017/02/05)
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- Tuning the self-assembly and photophysical properties of bi-1,3,4-thiadiazole derivatives through electron donor-acceptor interactions and their application in OLEDs
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We report several shape anisotropic molecules that contain two centrally placed 1,3,4-thiadiazole units, which vary from each other with respect to the number and length of the flexible chains at the termini. The number, position and length of the periphe
- Yadav, Abhay Kumar,Pradhan, Balaram,Ulla, Hidayath,Nath, Subrata,De, Joydip,Pal, Santanu Kumar,Satyanarayan,Achalkumar, Ammathnadu S.
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supporting information
p. 9345 - 9358
(2017/09/29)
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- Polarization effects in mesogenic isoxazoles and 1,3,4-oxadiazoles
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Four new series of unsymmetric isoxazoles and 1,3,4-oxadiazoles were prepared, characterized and their mesomorphic properties investigated. Isoxazoles were obtained by condensation-cyclization of β-diketones with hydroxylamine hydrochloride in refluxing T
- Lu, Li-Yang,Kuo, Hsiu-Ming,Sheu, Hwo-Shuenn,Lee, Gene-Hsiang,Lai, Chung K.
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p. 5999 - 6011
(2015/03/30)
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- Synthesis and anticonvulsant activity evaluation of 4-butyl-5-(4- alkoxyphenyl)-2H-1,2,4-triazole-3(4H)-ones
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A series of 4-butyl-5-(4-alkoxyphenyl)-2H-1,2,4-triazole-3(4H)-ones (6a-6u) was designed and synthesized. The anticonvulsant effects and neurotoxicity of the compounds were evaluated with maximal electroshock test and rotarod test. Among the synthetic compounds, 4-butyl-5-(4-(2-fluorinebenzyl)phenyl)-2H-1,2,4- triazole-3 (4H)-one (6k) was the most potent with ED50 value of 27.4 mg/kg and protective index (PI = TD50/ED50) value of 12.0. Besides the anti-MES efficacy, the potency of compound 6k against seizures induced by pentylenetetrazole (PTZ), 3-mercaptopropionic acid (3-MP), and bicuculline (BIC) was also established, which suggested that the mechanisms of action including enhancing of GABAergic activity might be involved in its anticonvulsant activity.
- Zhu, Zi-Shi,Wang, Shi-Ben,Deng, Xian-Qing,Liu, Da-Chuan,Quan, Zhe-Shan
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p. 628 - 635
(2014/05/20)
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- Synthesis, characterization and mesomorphic investigations of ester-substituted aroylhydrazones possessing a lateral hydroxyl group
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The synthesis, characterization and investigation of a new liquid crystalline series of ester containing aroylhydrazones with a lateral hydroxyl group, N-[4-(4′-alkoxy)benzoyloxy-2-hydroxy-benzylidene]-N′- [4″-alkoxybenzoyl]hydrazine (Cm,nLH), with the same or different peripheral alkoxy chains, and some of their nickel(II) and copper(II) complexes are described. All the ligands, except those with no terminal chains on either end of the molecule, exhibit an enantiotropic SmC mesophase, as evidenced by polarizing optical microscopy and differential scanning calorimetric studies. It has been found that addition of a lateral hydroxyl group along with ester-substitution to the aroylhydrazone core increases the mesomorphic as well as thermal stability of the ligands. Also, the coordination of Ni2+ and Cu2+ with the aroylhydraozone core inhibits the mesomorphic potential of the ligands. A temperature dependent Raman study of one of the members, C12,12LH (m = n = 12) has been made to identify phase transitions and to understand the molecular rearrangement as a result of changes in intermolecular interactions at the phase transition. DFT calculations have been performed to obtain the stable electronic structure of the ligand (C6,6LH) and its nickel(II) complex.
- Singh, Sachin Kumar,Singh, Hemant Kumar,Nandi, Rajib,Kumar, Vijay,Tarcea, Nicolae,Popp, Jürgen,Singh, Ranjan K.,Singh, Bachcha
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- Ligand-structure effect on the formation of one-dimensional nanoscale Cu(II)-schiff base complexes and solvent-mediated shape transformation
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We report here a Cu(II)-Schiff base complex that can assemble into one-dimensional (1D) nanoscale fibers, belts, and rods under different synthetic conditions. The ligand-structure effect is investigated by modification of the ligand structure. The format
- Wang, Wenjing,Chen, Qianhuo,Li, Qing,Sheng, Yu,Zhang, Xuanjun,Uvdal, Kajsa
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experimental part
p. 2707 - 2713
(2012/07/31)
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- Preparation and properties of oxadiazole-containing polyacetylenes as electron transport materials
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A series of functional polyacetylenes (PAs) bearing diphenyl oxadlazole pendant groups (P1-P4) were prepared, and the resultant polymers are completely soluble In common organic solvents, Their structures and properties were characterized and evaluated by
- Wang, Xin,Guan, Shanyi,Xu, Hongyao,Su, Xinyan,Zhu, Xuhui,Li, Chun
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scheme or table
p. 1406 - 1414
(2011/03/19)
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- Liquid crystals derived from semifluorinated alkoxybenzoyl hydrazines
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A variety of liquid crystals with semifluorinated tails including 4-alkoxybenzoic acids (1d-h), 4-alkoxybenzoyl hydrazines (2d-h), and N,N0-bis(4-alkoxybenzoyl) hydrazines (3d-m) have been synthesized, and their properties are compared with their perhydrogenated analogs. Semifluorination in compounds 1d-h suppressed nematic phases, and semifluorinated compounds 2d-h exhibit mesogenic behavior where none is found in their perhydrogenated counterparts. Compounds 3a-c with perhydrogenated chains display Cub and SmC phases. Introduction of one semifluorinated chain, 3d-h suppresses the Cub phase but induces a SmA phase, with lower melting but higher clearing temperatures compared to compounds with two semifluorinated chains, 3i-m. The mesogenic properties of some selected binary mixtures of these compounds 3a-d and some lateral fluoro substituted N,N'-bis (4-alkoxybenzoyl) hydrazines 7-9 are also discussed. Copyright Taylor & Francis Group, LLC.
- Khairuddean, Melati,Twieg, Robert J.
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experimental part
p. 3 - 31
(2012/08/13)
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- Thermally stable oxadiazole-containing polyacetylenes: Relationship between molecular structure and nonlinear optical properties
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Two novel high molecular weight functional polyacetylenes bearing oxadiazole groups as pendants, poly(2-(4-decyloxyphenyl)-5-(4-ethynylphenyl)-1, 3, 4-oxadiazole) (P1) and poly(2-(4-butyloxyphenyl)-5-(4-ethynylphenyl)-1, 3, 4-oxadiazole) (P2) were designe
- Wang, Xin,Guang, Shanyi,Xu, Hongyao,Su, Xinyan,Yang, Junyi,Song, Yinglin,Lin, Naibo,Liu, Xiangyang
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scheme or table
p. 4204 - 4209
(2010/02/28)
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- Synthesis and characterization of 1,3,4-oxadiazole derivatives containing alkoxy chains with different lengths
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The synthesis, optical properties, electrochemical properties, electronic structures and applications in electroluminescent device of three series of 1,3,4-oxadiazole derivatives, 1,4-bis[(4-methylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD1), 5,5′-di-(4-methyl)-2,2′-p-(2,5-bisalkoxyphenylene)-bis-1,3,4 -oxadiazole (OXD2-n) and 1,4-bis[(4-alkoxyphenyl)-1,3,4-oxadiazolyl]phenylene (OXD3-n) are reported. The molecular structures of the oxadiazole compounds were confirmed by FT-IR, 1H NMR spectroscopy and elemental analysis. The optical and electrochemical properties of the compounds were investigated by UV-vis absorption and photoluminescence spectroscopy as well as cyclic voltammetry. The results show that introduction of two alkoxy groups whose electron-donating ability is stronger than that of methyl groups increases the electron density of the conjugated segment of OXD2-n (with side-on alkoxy substituents) and OXD3-n (with end-on alkoxy substituents), and thus leads to the absorption maximum bathochromic-shift compared to that of OXD1. The HOMO and LUMO energy levels of the compounds studied are in the range of -2.78 to -2.89 and -5.75 to -6.20 eV. Calculations on the representative compounds by the Dmol3 package of MS Modeling 3.0 revealed that the increase of energy levels in both OXD2-n and OXD3-n was due to the change of the frontier molecular orbital distribution in the central benzene ring. The light-emitting devices have been fabricated using blends of MEH-PPV and these compounds as emissive layers, among which, maximum brightness up to 11810 cd m-2 (8.5 V) has been observed, which is 40 times brighter than that with MEH-PPV. The result of the devices suggested that oxadiazole derivatives studied function well as electron-transporting materials and can be used in LEDs, and thus to enhance the efficiency of LEDs.
- Zhang, Xiao-bing,Tang, Ben-chen,Zhang, Peng,Li, Min,Tian, Wen-jing
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- Synthesis and mesomorphic properties of azo compounds derived from phenyl- and thienyl-1,3,4-thiadiazole
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The synthesis and mesomorphic behaviour of new series of liquid crystals containing 1,3,4-thiadiazole and thiophene rings with azo central bond are reported (series 5a and 5b). All compounds of series 5a exhibit enantiotropic nematic mesophase and the hig
- Parra,Villouta,Vera,Belmar,Zú?iga,Zunza
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p. 1533 - 1538
(2007/10/03)
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- Aroylhydrazinatonickel(II) and Copper(II) Complexes; a New Class of Metallomesogens
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A series of aroylhydrazinato-nickel(II) and -copper(II) complexes have been synthesised in high yield and shown to form a new class of metallomesogens, which form smectic C and nematic phases; the nickel(II) complexes were found to be highly stable even i
- Abser, Mohammed N.,Bellwood, Martin,Holmes, Michael C.,McCabe, Richard W.
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p. 1062 - 1063
(2007/10/02)
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