Azobenzenes substituted

Shimomura, T. Funaki, T. Ito, K. Choi, B.-K. and Hashizume, T. (2002) Circular dichroism study of the inclusion-dissociation behavior of complexes between a molecular nanotube and azobenzene substituted linear polymers, J. Incl. Phenom. 44, 275-278. 

Photoresponsive host-guest systems based on azobenzene-substituted crown ethers have been shown to be particularly effective in the control of molecular recognition by light, due to their large geometrical changes upon E-Z isomerization. 55 A num-... 

Polymers containing chromophores such as acridine and azobenzene have also been prepared by palladium-catalyzed amination according to two approaches [222-224]. The first approach involved the polymerization of monomers containing the chromophore. For example, 4-aminoazobenzene was condensed with 1,3-dibromobenzene (Eq. (39)) or 4,4 -dibromobiphenyl ether to form polymeric materials with Mw values of 9.0 x 103 and 19 x 103, respectively. Alternatively, polymers prepared by polymerization of 4-bromostyrene or copolymerization of styrene and 4-bromostyrene were coupled with N-phenyl-4-amino azobenzene. Substitution of the aryl bromides by the amino azobenzene unit was essentially quantitative when using P(tBu)3 as the ligand. 

There are, however, azobenzenes that have wavelength-independent isomerization quantum yields and thus obey Kasha s rule. The structure of these molecules inhibits rotation. Rau and Liiddecke investigated azobenzeno-phane 9 and Rau the azobenzene capped crown ether 14, and these researchers found identical E,E —> E,Z, and E —> Z quantum yields respectively, regardless of which state was populated. The photoisomerization of azobenzenophanes and 13 could not be evaluated in the same way because the photoisomerization is intensity-dependent. A series of azobenzenes substituted in all ortho positions to the azo group has equal quantum yields for n —> n and k —> k excitation if the substituents are ethyl, isopropyl, tert.butyl, or phenyl. This provides clues for the elucidation of the isomerization mechanism (Section 1.6). 

Autret, M., Le Plouzennec, M., Molnet, C., and Sirnonneaux, G. (1994). Intramolecular Fluorescence Quenching in Azobenzene-substituted Porphyrins. J. Chem. Soc., Chem. Commun. 1169-1170. 

In sum, a larger repulsion between specific parts of the alkyl chains in a bilayer is reflected in a higher lateral pressure, a decrease in chain order and more area available for that part of the tails. Such changes can be induced by, for example, a higher temperature or introduction of a cis C=C bond into the tail or via trans-cis isomerization of double-tailed, azobenzene-substituted amphihiles. ... 

Figure 16.3 Schematic representation of a lateral pressure profile in a vesicular bilayer. Only one monolayer is shown here, the same profile applies for the other monolayer. The lateral pressure n depends on the depth (Z) in the monolayer. From M. Kuiper, Azobenzene-substituted Phosphate Amphiphiles Effect of Ught-induced trans-cis Isomerisation on Vesicular Properties and the Channel Protein MscL, Ph. D. Thesis, University of Groningen, p 2, 2005...

Ye L, Liu X, ZhangA, Feng P (2013) The preparation and characterization of dual stimuli-responsive novel triblock copolymers comprising azobenzene substituted polyrotaxane middle block flanked by PNIPAAm blocks. In ref. [18], 1395... 

This photo-induced chromic effect is reversible and the irradiated polymers slowly recover their initial absorptions features. Moreover, the same effect has been observed in solid state upon irradiation of thin film of azobenzene-substituted polythiophenes, opening the way to the design of novel photochromic polythiophenes that can be useful in a variety of optical devices. 

A copolymer (DCV-MMA) of methyl methacrylate and 4,4(dicyano-vinyl)-4 -(dialkylamino)azobenzene-substituted methacrylate (Fig. 4.9) formed by a novel azo coupling reaction [67] has been used [68] for corona poling and electro-optic experiments. The DCV-MMA has a Tg of 127 °C and when poled exhibits a 33 value of 5.1 x 10 esu, relaxing to 4.6. This... 

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