Synthesis and optical and transport properties of a phenyl-substituted polythiophene
作者:Siraye E. Debebe、Desta A. Gedefaw、Wendimagegn Mammo、Teketel Yohannes、Francesca Tinti、Alberto Zanelli、Valeria Fattori、Nadia Camaioni
DOI:10.1002/pola.24701
日期:2011.6.15
The synthesis and characterization of a novel polythiophene substituted with a 2′‐pentyloxy‐5′‐(1″′‐oxooctyl) phenyl group (PPOPT) is reported. The bulk transportproperties of thin films of PPOPT are investigated by admittance spectroscopy. The dramatic effect of the phenyl side chain on the mobility of positive carriers in films of PPOPT is described. The photophysics of PPOPT in both solution and
π-Conjugated Triphenylene Twins Exhibiting Polymesomorphism Including the Nematic Phase
作者:Sanjay Kumar Varshney、Hideo Takezoe、Veena Prasad、D. S. Shankar Rao
DOI:10.1080/15421400902987677
日期:2009.12.7
Novel discotic liquid crystals possessing two triphenylene (TP) mesogenic cores covalently connected via a rigid spacer, i.e., -conjugated ethynyl- or butadiynyl-bridge, (TP twins) are reported. The TP twins are categorized by the lengths of -substituted chains (R2 and R3) and peripheral alkoxy or branched aliphatic chains (R1 and R4). Three varieties of TP twins are prepared: A) TP twins having identical -substituted and peripheral chains (R1=R2=R3=R4), B) equivalent TP entities having a -substituted chain (R2=R3) and peripheral chains (R1=R4) of different length from the substitution, and C) TP twins with different TP entities having the same -substituted and peripheral alkoxy chains (R1=R2, R3=R4). The phase behavior is characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) studies. These TP twins exhibit a discotic nematic (N) and/or columnar rectangular (Colr) mesophases over a wide temperature range. We found that the relative length of rigid spacer and -substituted alkoxy chains play an important role in the creation of the molecular self-assembly and formation of the mesophases. To the best of our knowledge, this is the first report of TP twins exhibiting polymesomorphism.
Synthesis and Liquid-Crystalline Properties of β-Bromopentakis(Alkoxy) Triphenylene: Reactivity of VOCl<sub>3</sub>, MoCl<sub>5</sub>, and FeCl<sub>3</sub>as Oxidants
作者:Sanjay Kumar Varshney、Hiroki Nagayama、D. S. Shankar Rao、Hideo Takezoe
DOI:10.1080/15421406.2010.504514
日期:2010.10.14
We present a simple synthetic strategy leading to nonsymmetrical functionalized hexasubstituted triphenylene. Further, new -bromopentakis(alkoxy)triphenylene was synthesized applying this strategy and reactivity of oxidizing agents such as VOCl3, MoCl5, and FeCl3 was investigated. The liquid-crystalline properties were studied by polarizing optical microscope (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) studies. The higher homologues exhibit a columnar hexagonal (Colh) phase, whereas lower homologues also exhibit a columnar hexagonal plastic (Colhp) phase. These mesophases are stable below and above the ambient temperature. We studied the effect of polar substitution on molecular self-assembly and found that a bromo bulky substituent at the -position of pentakis(alkoxy)triphenylenes stabilized the intra- or intermolecular interaction between the cores to form columnar mesophases.
Micellar effects on the monohalogenation of n-pentyl phenyl ether
作者:David A. Jaeger、Raymond E. Robertson
DOI:10.1021/jo00440a022
日期:1977.9
2-PYRIDINE CARBOXAMIDE DERIVATIVES AS SODIUM CHANNEL MODULATORS