
	Where results make sense

Topic: Azobenzene

Related Topics

Photoisomerization

List of compounds

List of biomedical topics, A to E

Cypriot dialect

Cidade de Deus

	Azobenzene (CASRN 103-33-3) \| IRIS \| US EPA
		Azobenzene was positive in a reverse mutation plate incorporation assay in Salmonella (Ames test) upon addition of hepatic extracts for metabolism.
		Azobenzene causes DNA single strand breaks with <30% cytotoxicity by the alkaline elution/rat hepatocyte assay (Sina et al., 1983) and produces unscheduled DNA synthesis in human lymphocytes (Gaudin et al., 1971).
		It should be noted that azobenzene may be converted non-enzymatically under the acidic conditions in the stomach to the known human carcinogen benzidine.
	www.epa.gov /iris/subst/0351.htm (1111 words)

	NTP: Abstract for TR-154 - Azobenzene
		Azobenzene occurs as a by-product during the manufacture of benzidine.
		Azobenzene itself has no known uses as a dyestuff and is only produced in small quantities for research purposes.
		It is concluded that under the conditions of this bioassay, azobenzene was carcinogenic (sarcomagenic) for F344 rats, inducing various types of sarcomas in the spleen and other abdominal organs of both males and females.
	ntp-server.niehs.nih.gov /index.cfm?objectid=07051F9D-C2D6-772E-8ED2E7AD0F65D31A (553 words)

	recent-99-10-02e
		Azobenzene photo- isomerizes from trans to cis upon UV light irradiation and from cis to trans around 440 nm visible light.
		The mixture of 1 and 2 wt% of azobenzene derivative 2 (didodecyl azobenzene:Scheme 2) to 1 (dicholesteryl ester: Scheme 1) was melted between glass plates and cooled to a cholesteric temperature to obtain a thin film with a thickness of about 10 mu m.
		Moreover, it became clear that at cholesteric temperature, the helical pitch of cholesteric liquid crystal decreases with the photo isomerization of azobenzene, whereas once the liquid crystal is solidified, cis-2 formed by photo reaction isomerizes simply to trans-2 thermally, and the cholesteric reflection band is not affected by the isomerization of 2 at all.
	www.aist.go.jp /NIMC/recent/r99-10-02e.htm (1046 words)

	Woolley Lab Online: Publications
		Photoisomerization of the azobenzene core in the trans to cis direction is triggered by photon absorption but isomerization from cis to trans occurs thermally as well as photochemically.
		A water-soluble azobenzene cross-linker for photocontrol of peptide conformation.
		Irradiation of the peptide producing a conformational change in the azobenzene cross-linker was accompanied by an increase in the helicity of the peptide.
	www.chem.utoronto.ca /staff/GAW/papers.html (6185 words)

	NTP: ChemIDPlus/HSDB 103-33-3 Toxicity
		Azobenzene was tested by the oral route in mice and by the subcutaneous route in mice and rats.
		Azobenzene is non-carcinogenic in mice, but a potent rat carcinogen, inducing tumors in the spleen and other abdominal organs.
		Conventional rats metabolized azobenzene to hydrazobenzene and split to aniline due to the reductional and hydrolytic capability of the gut flora.
	ntp.niehs.nih.gov /index.cfm?objectid=E87BAD0A-BDB5-82F8-F7072D2B3C733162 (1723 words)

	COLL 211 - Incorporating azobenzene dyes into self-assembled and spin-assembled polyelectrolyte multilayers (Site not responding. Last check: 2007-11-02)
		Polyelectrolyte self assembled multilayers incorporating azobenzene dye molecules may be useful in fabricating new light sensitive optical materials.
		Initial studies were made on the kinetics of the polycation-azobenzene dye system, and on the incorporation of the azobenzene dye in a 10-bilayer system.
		A decrease in deposition of the azobenzene dye was observed when the films were prepared by spin assembly compared to self-assembly.
	membership.acs.org /c/coll/neworleans/P629447.HTM (192 words)

	AZOBENZENE (DIPHENYL DIIMIDE)
		Azobenzene is a compound composed of two phenyl rings linked by azo double bond.
		Azobenzene compounds are easily incorporated into polymer and rubber matrices and used as stabilizers of them.
		Azobenzene is used as a acaricide or fumigant directly.
	www.chemicalland21.com /industrialchem/organic/AZOBENZENE.htm (257 words)

	Dr. Paul Rochon RMC Physics (Site not responding. Last check: 2007-11-02)
		In these studies the azobenzene films are used as optical devices that can be made or altered in house to study various optical designs to achieve optical modulation.
		The azobenzene molecule is usually in the trans form, which can be considered to be uniaxial.
		We have found that in our typical polymer where the azobenzene is attached to the side on the methacrylate chain the light tends to move the polymer away from the high intensity regions into the low intensity regions.
	www.rmc.ca /academic/physics/rochon/index_e.html (1832 words)

	Solvent extraction of copper values using dihydroxy azoarenes - Patent 4003975
		The preferred extracting agents are the 2,2' dihydroxy azobenzenes with an alkyl substituent on at least one of the two benzene rings.
		When 0.1 grams of 2,2'-dihydroxy azobenzene was evaluated according to the above described test with the aqueous phase treated with sufficient sulfuric acid to achieve a pH of 2.29, it was found that 100 percent of the copper value was extracted into the organic phase.
		Proton NMR and Carbon 13 NMR indicated the presence of 10% 5-dodecyl-2,2'-dihydroxy azobenzene in the presence of a mixture of 5-dodecyl-2-hydroxy azobenzene and para-dodecyl phenol.
	www.freepatentsonline.com /4003975.html (2993 words)

	Pacifichem 2005 Symposia (Site not responding. Last check: 2007-11-02)
		Azobenzene is a very interesting photochromic molecule, which can be switched quickly and reversibly between 2 geometric forms using light.
		The focus will be equally placed on preparation routes to new and interesting materials containing azobenzene (both polymer and small molecule), and study of the photoswitchable properties which are common to the various materials and applications.
		Papers on azobenzene material synthesis, characterization, processing, self-assembly, order/disorder, morphology/rheology, surface science, bio-activity, optics, photonics, and all other potential applications are all welcome.
	www.pacifichem.org /c_symposia/c_symp_133.htm (219 words)

	03.Surface Science (Site not responding. Last check: 2007-11-02)
		The structure and growth of functionalized thiol self-assembled monolayers (SAMs) on Au(111) derived from a new compound, 12-(4-((4-hexylphenyl)azo)phenoxy)dodecane-1-thiol ("hexyl azobenzene thiol"), were examined by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), dynamic contact angles, Fourier transform infrared-reflection absorption spectroscopy (FTIR-RAS), and reflection UV-vis absorption spectroscopy.
		At the initial stage of SAM growth, formation of nanosize domains resulting from the rearrangement of molecules on the surface was confirmed in a similar manner as for alkanethiol SAMs with long alkyl chains.
		The hexyl azobenzene thiol SAM exhibited a unique molecular ordering due to the intermolecular interaction between tail groups.
	www.aist.go.jp /NIMC/publication/annual98/03/03_2.html (243 words)

	Anais da Academia Brasileira de Ciências - Supramolecular effects in dendritic systems containing photoactive groups (Site not responding. Last check: 2007-11-02)
		The peripheric azobenzene groups in these dendrimeric compounds can be regarded as single residues that retain the spectroscopic and photochemical properties of free azobenzene moiety.
		The total number of azobenzene residues for the first, second, third and fourth generations (G1 to G4) is respectively 4, 8, 16 and 32.
		The azobenzene units in these dendrimeric compounds can be regarded as single residues that retain the spectroscopic and photochemical properties of the free azobenzene moiety.
	www.scielo.br /scielo.php?script=sci_arttext&pid=S0001-37652000000100004 (1343 words)

	Research
		For example, when an azobenzene structure is introduced to LC molecules as the photosensitive moiety, the photochemical LC-to-isotropic phase transition takes place isothermally by the trans-cis photoisomerization of the azobenzene.
		Observation of the grating structure with a polarizing microscope confirmed that the isotropic phase was arranged with a spatial resolution of < 1 micrometer which corresponds to a storage capability of > 400 Mbits/cm2.
		Hologram Based on Photoinduced Alignment of LC Molecules: When azobenzene LC polymer films were irradiated with linearly polarized light, the reorientation of LC molecules was brought about with the molecular long axis perpendicular to the polarization direction of light.
	www.res.titech.ac.jp /~polymer/research-e-frame2.html (584 words)

	CSIRO PUBLISHING - Australian Journal of Chemistry
		Azobenzene reduces in two one-electron steps, as is thecase in acetonitrile and dimethylformamide.
		Acetic acid exhibits a single irreversible proton reduction wave.On addition of acid, azobenzene is reduced to hydrazobenzene via azoniumbenzene formed by protonation of azobenzene.
		In pyridine the reduction of azobenzene in the presence of proton donors is similar to that observed in acetonitrile.
	www.publish.csiro.au /?paper=CH9741623 (187 words)

	Brinker Nanostructures Research Group - Current Research
		Incorporation of covalently-bonded, “switchable” azobenzene ligands as pendant groups within a porous framework is expected to result in nanocomposites with dynamically controllable pore size (Fig.
		The measured oxidative current increased and decreased in response to alternating UV and visible light exposure, which correlates strongly with the photoisomerization state of the azobenzene ligands (Fig.
		This indicates that the optically switchable conformation (trans or cis) of azobenzene ligands controls the effective pore size, and, correspondingly, transport behavior on the nanoscale.
	www.unm.edu /~solgel/research/nanguo_nanovalves.html (347 words)

	Azobenzene
		The chemical structure of Azobenzene is shown at the right.
		This is a graph of the molar extinction coefficient of Azobenzene dissolved in benzene.
		Azobenzene has a molar extinction coefficient of 22,387 M
	omlc.ogi.edu /spectra/PhotochemCAD/html/azobenzene.html (137 words)

	Research: azobenzene monolayers
		The orientation and packing of the molecules within the monolayer affect their optical characteristics which can be used in the eventual design of molecular machines.
		This two-dimensional molecular assemblies provide the opportunity to study light-triggered changes in their structure which are dependent on their molecular orientation and aggregation state.
		We are currently working on the elucidation of the combination of mechanisms which may account for the dynamic behaviour of the photostationary states of some Lagmuir monolayers of azobenzenes containing the mesogenic trans-isomer as a major component, under different conditions of light phototriggering.
	www.qf.ub.es /d1/research_azo.html (454 words)

	H-Aggregation of Azobenzene-Substituted Amphiphiles in Vesicular Membranes
		Since the ease of switching depends on the strength of the bilayer packing, particular emphasis has been placed on the occurrence of H-aggregation in the hydrophobic core of the vesicles.
		UV-vis spectrometry was employed to monitor H-aggregation and showed how this process depends on the ionic strength and on the mode of preparation of the vesicles.
		Two types of H-aggregates were observed in mixed DOPC vesicles with 5 mol % of azobenzene phosphate: one with λmax at around 300nm and one with λmax at 305-320 nm.
	stratingh.eldoc.ub.rug.nl /root/EngbertsJBFN/2004/LangmuirKuiper (243 words)

	Molecular 'Scissors' Work in Response to Light
		Driving the motion are two handles strapped with photoresponsive molecules called azobenzene, which not only has the ability to absorb light, but comes in two isomeric forms: a long-form and short-form.
		Upon exposure to ultraviolet (UV) light, the long-form of azobenzene is converted into the short-form.
		When UV and visible light are used interchangeably, the length of the azobenzene decreases and increases, which drives the handles in an open-close motion.
	photonics.com /content/news/2007/March/26/86996.aspx (679 words)

	Photo-induced phase transitions in azobenzene-doped liquid crystals
		The effect of irradiation (UV-visible light) on a nematic liquid crystal doped with a photoactive azobenzene derivative was investigated.
		The authors investigate the cause and magnitude of the phase depression as a function of the amount of doped 4-butyl-4'-methoxyazobenzene (photoactive unit) in 4-cyano-4'-n-pentylbiphenyl (liquid crystal unit), and as a function of the percentage conversion of E implies Z (caused by isomerization) in the azobenzene.
		The photostationary state of the doped mixtures achieved by Z implies E isomerization is considered and its effect upon the transition temperature of the mixture and response time of the system is discussed.
	stacks.iop.org /0022-3727/25/492 (320 words)

	L. Grill - Latest News - Azobenzene Isomerization
		We studied TBA molecules, which are azobenzene derivatives equipped with four tert-butyl "legs", on a Au(111) surface.
		While at rather small tip heights (below 9.5 Å) the process is related to the tunnelling electrons, the linear relationship at larger heights shows that the isomerization is driven by the electric field in the junction.
		This observation, which has been proposed recently by theoretical calculations, is the first experimental evidence of an electric-field induced isomerization process of azobenzene molecules or derivatives (and, to our knowledge, of any molecular switches).
	www.physik.fu-berlin.de /~grill/research/isomerization (227 words)

	Peptide packs in holographic data - Brief Article Science News - Find Articles
		The original azobenzene peptides appeared promising, but "one of the major drawbacks was the response time," says Bernard Kippelen of the University of Arizona's Optical Sciences Center in Tucson.
		Films of a two-unit peptide made up of copies of the dye azobenzene (orange) attached to proline amino acids (blue) can be used as a medium for storing data holographically.
		Although azobenzene peptides are among several promising potential holographic materials, many issues must be resolved before they can become practical for data storage.
	findarticles.com /p/articles/mi_m1200/is_21_155/ai_54859140?lstpn=article_results&lstpc=search&lstpr=external&lstprs=other&lstwid=1&lstwn=search_results&lstwp=body_middle (597 words)

	Woolley Lab Online: Research Interests
		In the dark, at equilibrium, azobenzene is >99% trans.
		Cis and trans isomers of azobenzene different significantly in structure and dipole moment.
		In this configuration, trans→cis isomerization introduces a dipole at the center of the membrane oriented such that the positive end of the dipole is directed at the cation path (Fig.
	www.chem.utoronto.ca /staff/GAW/research.html (2100 words)

	The brightest azobenzene
		It is substituted with a boron group and shows 30 000 fold light emitting efficiency compared to the unsubstituted azobenzene.
		Azo dyes, derivatives of azobenzene, are very frequently used as dyes.
		Takayuki Kawashima and coworkers from the University of Tokyo, were studying the effects of adding main group substituents to the nitrogen in the 2-position of the azobenzene.
	www.rsc.org /Publishing/Journals/cc/News/B615966D_Kawashima_110107.asp (201 words)

	Tiny Motor, Giant Leap - Popular Science
		The azobenzene molecule has two configurations (above): the trans-configuration and the shorter cis-configuration.
		Azobenzene, a polymer molecule, has a unique characteristic: It changes from one shape to another when exposed to light of different wavelengths.
		Then they exposed the azobenzene to alternate wavelengths of light.
	www.popsci.com /popsci/science/db51359b9fa84010vgnvcm1000004eecbccdrcrd.html (319 words)

	Index
		We have compared the UV-Vis absorption spectra, the trans-to-cis photoisomerization and the cis-to-trans thermal isomerization of azobenzene peptides with those of precursor 4,4´-diaminoazobenzene, 4,4´-dicarboxylic acid azobenzene and parent azobenzene.
		The chain elongations of both the push-push and pull-pull azobenzenes by amide group with alanine residues cause the rate reduction in all cases.
		The rate reduction of amide derivatives from push-push azobenzene is more significant than that of amide derivatives from pull-pull azobenzene.
	nbn-resolving.de /urn/resolver.pl?urn=urn:nbn:de:hbz:294-15460 (148 words)

	Almeria Natansohn
		X-ray investigations of formation efficiency of buried azobenzene polymer density gratings.
		Photoinduced birefringence and surface relief gratings in novel polyurethanes with azobenzene groups in the main chain.
		Synthesis of polymers containing azobenzene side groups bound to the main chain through an electron donor or an electron acceptor substituent.
	www.chem.queensu.ca /people/faculty/publications/natansohn.htm (1908 words)

	Molecular 'Scissors' Work in Response to Light
		Driving the motion are two handles strapped with photoresponsive molecules called azobenzene, which not only has the ability to absorb light, but comes in two isomeric forms: a long-form and short-form.
		Upon exposure to ultraviolet (UV) light, the long-form of azobenzene is converted into the short-form.
		When UV and visible light are used interchangeably, the length of the azobenzene decreases and increases, which drives the handles in an open-close motion.
	www.photonics.com /content/news/2007/March/26/86996.aspx (715 words)

Try your search on: Qwika (all wikis)