27914-60-9Relevant articles and documents
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)
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.
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
, p. 5836 - 5845 (2011)
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.
Design and phase transition behavior of siloxane-based monomeric and dimeric liquid crystals bearing cholesteryl mesogenic groups
Katsuki, Kaito,Kaneko, Kosuke,Kaneko, Kimiyoshi,Kato, Riki,Miyamoto, Nobuyoshi,Hanasaki, Tomonori
, p. 34 - 39 (2019)
A series of siloxane-based monomeric and dimeric liquid crystals (LCs) bearing cholesteryl mesogenic groups were newly synthesized and their phase transition behavior was investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). All the siloxane-based LCs obtained in this study showed a smectic A phase in a wide temperature range. Among the siloxane-based LCs obtained, only the dimeric LC with a shortest siloxane unit at a central part of a spacer was found to exhibit a chiral nematic phase and a blue phase in addition to the smectic A phase. The difference in the thermal properties of the siloxane-based dimeric LCs was investigated in terms of their conformations. Furthermore, the results obtained for the siloxane-based LCs were discussed with comparing with those of homologues having the normal alkyl chains and spacers.
Full-spectrum selective reflection annular side chain liquid crystal oligomer film and preparation method thereof
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Paragraph 0049; 0054; 0057-0058, (2021/08/06)
The invention discloses a full-spectrum selective reflection annular side chain liquid crystal oligomer film and a preparation method thereof. The preparation method comprises the following steps: respectively carrying out graft copolymerization on a chiral liquid crystal monomer and an achiral rod-like monomer or two chiral liquid crystal monomers and annular polymethyl hydrogen-containing siloxane to construct the full-spectrum selective reflection annular side chain liquid crystal oligomer film, the structural formula is shown as a formula I. The cyclic side chain liquid crystal oligomer can realize full-spectrum selective reflection in the heating process; at room temperature, the annular side chain liquid crystal oligomer film can realize full-spectrum selective reflection along with the change of an incident angle. The cyclic side chain liquid crystal oligomer prepared by the method has dual characteristics that dynamic full-spectrum selective reflection changes along with temperature and incident angle, and has a wide application prospect in the optical field, the preparation process is safe to operate, and reaction conditions are mild.
TRUNCATED ITRACONAZOLE ANALOGUES AND METHODS OF USE THEREOF
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Paragraph 0097; 0101, (2021/02/19)
Disclosed herein are analogues of itraconazole that are potent hedgehog signaling pathway inhibitors. The compounds are expected to be useful in the treatment of cell proliferation disorders such as cancer, particularly cancers that are dependent upon the hedgehog signaling pathway such as basal cell carcinoma and medulloblastoma.
Visible-Light-Induced Deoxygenation/Defluorination Protocol for Synthesis of γ,γ-Difluoroallylic Ketones
Guo, Yuan-Qiang,Wang, Ruiguo,Song, Hongjian,Liu, Yuxiu,Wang, Qingmin
supporting information, p. 709 - 713 (2020/01/31)
Herein, we describe an efficient, practical photocatalytic deoxygenation/defluorination protocol for the synthesis of γ,γ-difluoroallylic ketones from commercially available aromatic carboxylic acids, triphenylphosphine, and α-trifluoromethyl alkenes. The protocol has good functional group tolerance and a broad substrate scope. Using this method, we accomplished the late-stage functionalization of several bioactive molecules.
