نتایج جستجو برای: phenylene terephthalamide

تعداد نتایج: 2167  

Journal: :Molecules 2011
Alejandro Madrid Villegas Luis Espinoza Catalán Iván Montenegro Venegas Joan Villena García Héctor Carrasco Altamirano

Catechols were synthesized from safrole. Nine derivatives were prepared and assessed for antiproliferative effects using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. The derivatives 4-allylbenzene-1,2-diol (3), 4 4-[3-(acetyloxy)propyl]-1,2-phenylene diacetate (6) and 4-[3-(acetyloxy)propyl]-5-nitro-1,2-phenyle...

2017
Ashlea R Hughes Nick J Brownbill Rachel C Lalek Michael E Briggs Anna G Slater Andrew I Cooper Frédéric Blanc

Using variable temperature 2 H static NMR spectra and 13 C spin-lattice relaxation times (T1 ), we show that two different porous organic cages with tubular architectures are ultra-fast molecular rotors. The central para-phenylene rings that frame the "windows" to the cage voids display very rapid rotational rates of the order of 1.2-8×106  Hz at 230 K with low activation energy barriers in the...

Journal: :Dalton transactions 2013
Mirtha A O Lourenço Renée Siegel Luís Mafra Paula Ferreira

N-alkylation reaction of amine functionalized phenylene moieties in crystal-like mesoporous silica is successfully achieved with about 87% of conversion in two reaction cycles. A potassium iodide catalyzed method commonly used for the selective N-monoalkylation of aniline is adapted and optimized to the N-monoalkylation reactions of the amine functionalized periodic mesoporous phenylene-silica ...

2008
Zhi-Qiang Wang Chen Xu Ying-Fei Li Fei-Fei Cen Yu-Qing Zhang

The mol-ecule of the title compound, C(16)H(24)N(2)O(6), which lies on a crystallographic inversion centre in the centre of the benzene ring, adopts an anti conformation in terms of the relative orientation of two amide carbonyl groups. One pair of the 2-hydroxy-ethyl groups is partially disordered with site occupancy factors of 0.811 (2) and 0.189 (2). The dihedral angle between the amide grou...

In this paper, new (2E, 2'E)-3, 3'-(((3- hydroxypropane-1, 2-diyl) bis (oxy)) bis (2, 1-phenylene)) bis (1-phenylprop-2-en-1-one) (2a) was prepared in good yield by condensation reaction of acetophenone with bisaldehyde (1a) in ethanolic NaOH solutions at room temperature. The (2E, 2'E)-3, 3'-(((3- hydroxypropane-1, 2-diyl) bis (oxy)) bis (2, 1-phenylene)) bis (1-phenylprop-2-en-1-one) (2a) was...

Journal: :Chemical communications 2011
Thomas A Albright Sander Oldenhof Oluwakemi A Oloba Robin Padilla K Peter C Vollhardt

Cyclopentadienylcobalt complexes of linear [4]phenylene undergo thermally reversible photoinduced metallahaptotropism between the inner and outer cyclobutadiene ring.

Journal: :Journal of the American Chemical Society 2002
Zhengguo Zhu Timothy M Swager

Stable solutions of conjugated poly(phenylene vinylene)s and poly(phenylene ethynylene)s in nematic liquid crystals are reported. The polymers all contain triptycene units fused into their backbones to obtain the high solubility needed to maintain solubility in complex liquid crystalline media. The polymer backbones align with the director of the nematic liquid crystal, and by applying electric...

Journal: :Chemistry 2003
Lior Eshdat Roy E Hoffman Andreas Fechtenkötter Klaus Müllen Mordecai Rabinovitz

Hexa(4-n-dodecylbiphenylyl)benzene (HDBB) was reduced by a series of alkali metals in THF under high vacuum. Three reduction states were identified by NMR spectroscopy, namely the dianion, tetraanion and hexaanion. The NMR spectra of HDBB(6-) revealed a remarkable distortion of symmetry, which is interpreted by adoption of a twisted conformation of the central benzene ring and a slow rotation o...

2000
P. A. Lane A. J. Cadby H. Mellor S. J. Martin D. G. Lidzey D. D. C. Bradley W. J. Blau

We have investigated the photophysics of the luminescent polymer poly~1,3-phenylenevinylene-alt-2,5dioctyloxy-1,4-phenylenevinylene! by a variety of optical spectroscopies. The incorporation of alternating meta-phenylene and para-phenylene rings restricts conjugation with respect to poly~para-phenylenevinylene! derivatives. As a consequence, excited states are blueshifted and the nonlinear susc...

2009
Maher A. Qaddoura Kevin D. Belfield

Several divinylic mesogenic monomers were synthesized based on coupling the monomer 4-(4-pentenyloxy)benzoic acid with chlorohydroquinone, 2,5-dihydroxy- acetophenone, methylhydroquinone or 2-methoxyhydroquinone. This resulted in novel mesogens of phenylene esters with different lateral substituent groups. The effect of the lateral substituent group on the thermotropic phase behavior for these ...

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