5443-37-8Relevant academic research and scientific papers
Self-assembly of bistriazole BDT based bolaamphiphiles into SmA phase and helical organogels
Cheng, Xiaohong,Gao, Hongfei,Liu, Yuantao,Yan, Qi,Zhang, Deling
, (2021/01/12)
Bistriazole benzo[1,2-b:4,3-b′]dithiophene (BDT) contained bolaamphiphiles have been synthesized via Sonogashira coupling and click reactions as key steps. For such compounds, the central bent bistriazole BDT core, the flexible methylene spacer led the rodlike core together with the terminal diol groups to twist to be U-shaped polar region. Micro-segregation of U-shaped polar region from the lipophilic chains generated a SmA phase. Furthermore, these compounds can act as super organogelators to gel different kinds of solvents with the lowest critical gelation concentration (CGC) of 0.2 mg/ml. Gel morphologies with scarcely reported nanostructures including nanofibers, nanobelts, nanodisks, nanotrumpets and nanotubes were firstly observed in bolaamphiphilic self-assembly system.
Enantioselective Construction of Si-Stereogenic Center via Rhodium-Catalyzed Intermolecular Hydrosilylation of Alkene
He, Tao,Liu, Li-Chuan,Ma, Wen-Peng,Li, Bin,Zhang, Qing-Wei,He, Wei
supporting information, p. 17011 - 17015 (2020/11/30)
Catalytic, enantioselective synthesis of stereogenic silicon compounds remains a challenge. Herein, we report a rhodium-catalyzed regio- and enantio-selective intermolecular hydrosilylation of alkene with prochiral dihydrosilane. This new method features a simple catalytic system, mild reaction conditions and a wide functional group tolerance.
A series of novel side chain liquid crystalline polysiloxanes containing cyano- and cholesterol-terminated substituents: Where will the structure-dependence of terminal behavior of the side chain reappear?
Yao, Wenhuan,Gao, Yanzi,Zhang, Cuihong,Li, Chenyue,Li, Fasheng,Yang, Zhou,Zhang, Lanying
, p. 1765 - 1772 (2017/04/13)
A series of polysiloxane side chain liquid crystal polymers with strong polarity cyano substitution-terminated achiral side chains and cholesterol-terminated chiral side chains was successfully synthesized via thiol-ene click chemistry. 1H-NMR, FT-IR, and thermogravimetric analysis were used to confirm their chemical structures and thermal stabilities. Their phase transition behaviors and phase structures were systematically investigated by a combination of analysis methods such as differential scanning calorimetry, polarized optical microscopy, and X-ray. Results revealed that attributing to the decisive role of the polarity interaction, all the polymers only developed a monolayer interdigitated SmA phase in which the period arrangement was determined by the cyano-terminated side chains, the increased content of cholesterol-terminated chiral side chains (Xchol) just expanded the distance between neighboring molecules within a layer.
Synthesis and self-assembly behaviours of side-chain smectic thiol-ene polymers based on the polysiloxane backbone
Yao, Wenhuan,Gao, Yanzi,Yuan, Xiao,He, Baofeng,Yu, Haifeng,Zhang, Lanying,Shen, Zhihao,He, Wanli,Yang, Zhou,Yang, Huai,Yang, Dengke
, p. 1425 - 1440 (2016/02/23)
A series of polysiloxane side chain liquid crystal polymers (PSCLCPs) with chiral and achiral substitutions in the side chains, denoted as PMMS-Xchol-n (n = 0, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5 0.6, 0.7. 0.8, 0.9, and 1.0, respectively, the molar content of the chiral cholesteric unit (Xchol) in a specific polymer), were successfully synthesized via thiol-ene click chemistry. The molecular structures of the polymers were confirmed by 1H-NMR, FT-IR, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). Their liquid crystalline (LC) properties and self-assembling behaviors were investigated in detail by a combination of various techniques, such as differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction. The results demonstrated that the phase transition behaviour and the self-assembly structure of the polymers were significantly influenced by Xchol and temperatures. With increased Xchol, the clearing points increased significantly, their mesogenic temperature ranges greatly widened, and abundant mesophases developed. Generally, two different types of LC phase structures and three different molecular arrangements were observed, depending on the two LC building blocks. Polymers with Xchol below 0.3 could self-assemble into a smectic E (SmE)-like structure and a single layer smectic A (SmAs) structure upon heating. When Xchol was between 0.4 and 0.7, a single phase structure of a SmAs or a bilayer smectic A (SmAd) could be observed. While for polymers with Xchol over 0.8, a SmAd phase structure was self-organized, further heating led to a SmAs structure. Moreover, when the molar ratio of the chiral group or achiral group was about 0.1, a microphase-separated smectic morphology could be found, indicating that the introduction of a small amount of any components in the copolymers might destroy the well-ordered structures.
Synthesis and characterization of liquid crystalline organosiloxanes containing 4-methoxyphenyl 4-(2-alkenyloxy)benzoate
Chen, Cheng-Chih,Lin, Chih-Hung
, p. 1270 - 1274 (2016/04/10)
A series of new organosiloxane liquid crystalline materials based on the 4-methoxyphenyl-4-(ù-alkenyloxy)benzoate as mesogenic units have been synthesized and their mesomorphic and physical properties have been characterized. A series of new disiloxanes and trisiloxanes contain 4-methoxyphenyl 4-(ù-alkenyloxy)benzoate as mesogenic these were synthesized by addition of 4-methoxyphenyl 4-(ù-alkenyloxy)benzoate moiety to pentamethylhydrodisiloxane or heptamethylhydrotrisiloxane catalyzed by platinum divinyltetramethyldisiloxane complex. The thermal properties of this new series of thermotropic liquid-crystalline siloxanes were studied by differential scanning calorimetry and polarized optical microscope. Disiloxane series compounds were not showed any liquid crystal phase. Trisiloxanes series compounds exhibited nematic liquid crystal phase. The siloxane molecule helped to reduce the melting temperature. The thermal properties of the new siloxane series exhibited a pronounced odd-even effect with the length of alkyl segment.
Influence of shorter backbone and cholesteric monomer percentage on the phase structures and thermal-optical properties of linear siloxane tetramers containing cholesterol and benzene methyl ether groups
Yao, Wenhuan,Gao, Yanzi,Li, Fasheng,Zhang, Lanying,Yang, Zhou,Yang, Huai
, p. 87502 - 87512 (2016/09/23)
A series of new linear polysiloxane tetramers containing cholesterol and benzene methyl ether groups as side chains was successfully synthesized via a typical hydrosilylation reaction. Their chemical structures were confirmed by 1H-NMR, FT-IR and thermogravimetric analysis (TGA). A combination of analysis methods such as differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction was carried out to systematically investigate their phase transition behaviours and phase structures. The results revealed that the mesophase structures of all the polymers were greatly dependent on the molar content of the chiral cholesteric unit (Xchol). Polymers with Xchol below 0.60 or over 0.70 could develop a stable cholesteric phase or smectic A phase, while both smectic A and cholesteric phases could be formed for polymers with Xchol between 0.60 and 0.70. Besides, polymers with Xchol below 0.60, which developed a cholesteric phase with sufficiently wide temperature ranges in the entire mesomorphic state (minimum over 50 °C and maximum over 130 °C), could also exhibit tunable selective reflection wavelengths between 470-560 nm upon heating and arbitrarily regulated glass transition temperatures between 0-40 °C. As a result, a thermochromism liquid crystalline material for temperature sensors was successfully obtained. Surprisingly, different from the results previously reported, an unusual phenomenon of the centre selective light reflection wavelength (λm) vs. Xchol, which decreased dramatically (blue shift) at first, then had a remarkable red shift with increasing Xchol, was first observed.
Laterally connected bent-core dimers and bent-core-rod couples with nematic liquid crystalline phases
Shanker, Govindaswamy,Prehm, Marko,Tschierske, Carsten
supporting information, p. 168 - 174 (2013/01/12)
First examples of laterally connected bent-core dimesogens and liquid crystalline dimesogens involving bent-core units and rod-like units are reported. Four distinct types of dimesogens have been synthesized and investigated by polarizing microscopy (PM),
Wide-band reflective films produced by side-chain cholesteric liquid-crystalline elastomers derived from a binaphthalene crosslinking agent
Wu, Xiaojuan,Yu, Lilong,Cao, Hui,Guo, Renwei,Li, Kexuan,Cheng, Zihui,Wang, Feifei,Yang, Zhou,Yang, Huai
experimental part, p. 5836 - 5845 (2012/04/04)
A series of novel side-chain cholesteric liquid-crystalline elastomers based on polysiloxane and cholesterol derivate monomer were prepared by adopting a crosslinking agent containing binaphthalene group. The chemical structures and mesomorphic properties of the monomers and elastomers were confirmed by FT-IR, 1H NMR, DSC and POM measurements. Worthily, the elastomers exhibited unusual temperature dependence of the helical twisting power (HTP) which is demonstrated resulting from coordination of the crosslinking agent and the mesogenic units. With increase in temperature, the HTP of elastomers containing small quantity of the crosslinking unit exhibited a turning point, while that of elastomers comprising much more crosslinking unit shifted straight. Furthermore, a single layer wide-band reflective film with non-uniform pitch distribution was prepared by utilizing the HTP variety of elastomers with change in temperature. From scanning electron microscopy (SEM) investigations, the mechanism of the broadband reflection was verified.
Concise strategy for the synthesis of elevenmembered and ansa-bridged thirteen-membered lactone macrolides by ring-closing metathesis reaction
Majumdar, Krishna C.,Chattopadhyay, Buddhadeb,Ansary, Inul
experimental part, p. 472 - 477 (2009/10/17)
The eleven-membered macrolides and thirteen-membered ansa-bridged macrolides have been synthesized successfully ring-closing metathesis reaction in the absence of the additive Ti(OiPr)4, which is essential for the metathesis of the ester precursors.
Synthesis of 1-(2,4-dichlorophenyl)-4-cyano-5-(4-[11C] methoxyphenyl)-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide ([ 11C]JHU75528) and 1-(2-bromophenyl)-4-cyano-5-(4-[ 11C]methoxyphenyl)-N-(piperidin-1-yl)-1H-pyrazole-3-c
Fan, Hong,Ravert, Hayden T.,Holt, Daniel P.,Dannals, Robert F.,Horti, Andrew G.
, p. 1021 - 1036 (2007/10/03)
Two novel ligands for cerebral cannabinoid receptor (CB1), 1-(2,4-dichlorophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin-1-yl) -1H-pyrazole-3-carboxamide (JHU75528) and 1-(2-bromophenyl)-4-cyano-5-(4- methoxyphenyl)-N-(piperidin-1-yl)-1H-pyrazole-3-carb
