Azobenzenes organization

Liu Z, Loo B FI, Baba R and Fu]ishima A 1990 Exoellent reversible photoohromio behaviour of 4-ootyl-4 -(5-oarboxyl-pentamethyleneoxy)-azobenzene in organized monolayer assemblies Chem. Lett. 1023-6... 

Problem 24.19 Propose a synthesis of y>(dimelhylamino)azobenzene from benzene as your only organic starting material. 

Organic synthesis 38 [OS 38] Formation of an azobenzene derivative from N,N-dimethylaniline with 4-nitrobenzenediazonium tetrafluoroborate... 

Organic synthesis 39 [OS 39) Formation of azobenzene derivatives for pigment production... 

Kang, E.-H. Bu, T. Jin, R Sun, J. Yang, Y. Shen, J. 2007. Layer-by-layer deposited organic/inorganic hybrid multilayer films containing noncentrosymmetrically orientated azobenzene chromophores. Langmuir 23 7594-7601. 

Organic compounds which show reversible color change by a photochemical reaction are potentially applicable to optical switching and/or memory materials. Azobenzenes and its derivatives are one of the most suitable candidates of photochemical switching molecular devices because of their well characterized photochromic behavior attributed to trans-cis photoisomerization reaction. Many works on photochromism of azobenzenes in monolayers LB films, and bilayer membranes, have been reported. Photochemical isomerization reaction of the azobenzene chromophore is well known to trigger phase transitions of liquid crystals [29-31]. Recently we have found the isothermal phase transition from the state VI to the state I of the cast film of CgAzoCioN+ Br induced by photoirradiation [32]. 

Larson et al. (1992) studied the photosensitizing ability of 2, 3, 4, 5 -tetraacetylriboflavin to various organic compounds. An aqueous solution containing aniline was subjected to a medium-pressure mercury arc lamp (X >290 nm). The investigators reported that 2, 3, 4, 5 -tetraacetylribofiavin was superior to another photosensitizer, namely riboflavin, in degrading aniline. Direct photolysis of aniline without any photosensitizer present resulted in a half-life of 23 h. In the presence of riboflavin and 2, 3, 4, 5 -tetraacetylribofiavin, the half-lives were 1 min and 45 sec, respectively. Photoproducts identified in both reactions were azobenzene, phenazine, and azoxybenzene. 

Weber and Wolfe (1986, 1987) reported that azobenzene, when incubated in air with four anaerobic lake sediments containing about 2-4% organic matter, was reduced to aniline with a reaction half- life of about 2700-5700 minutes, depending on the source and date of specimen collection. 

Food Chain Bioaccumulation. 1,2-Diphenylhydrazine reacts rapidly in water to form azobenzene and other oxidation products (half-life in wastewater is 60 minutes). Because of this and based upon the log octanol/water partition coefficient, no bioaccumulation is expected in any aquatic organism. 

Harada J, Ogawa K (2001) Invisible but common motion in organic crystals a pedal motion in stilbenes and azobenzenes. J Am Chem Soc 123 10884-10888... 

It is well known that nitrogen-containing ligands are readily metallated by paHadium(II). The first reaction of this type was described in 1965 by Cope et al.1 for azobenzene. Since then numerous examples of similar reactions have been described in the literature.2 These cyclometallated compounds have been shown to be reactive intermediates in organic synthesis, especially in the... 

What structural features are required in order to allow an organic compound to absorb sunlight at a significant rate Give examples of compounds that absorb sunlight (a) only in the uv-range, (b) in both the uv and visible range. What color is a concentrated solution of azobenzene (Fig. 15.2d and Table 15.2) ... 

The incorporation of a cationic azobenzene derivative, p-( a> -dimethyl-ethanolammonioethoxyj-azobenzene bromide, into nanoporous silica films and the photochemical reactions of the adsorbed dye were investigated. The nanoporous silica films were prepared from tetramethoxysilane and octadecyltrimethyl-ammonium chloride by the rapid solvent evaporation method which we have reported previously. The adsorption of the cationic azo dye was conducted by casting an ethanol solution of the dye onto the nanoporous silica films. Upon UV light irradiation, trans-azobenzene isomerized photochemically to the c/s-form and photochemically formed c/ s-form turned back to the frans-form upon visible light irradiation. The nanoporous silica films were proved to be an excellent reaction media to immobilize organic photocromic species. 

We now report the photochromic reaction of an azobenzene in the nanoporous silica film. Since the photochromic behavior is environmentally sensitive, photochromism of organic substances in solid matrices has been investigated to understand as well as to modify the photochromic behavior.[21] Photochromism of azobenzene and its derivatives due to cis-trans isomerization (Scheme I) has widely been investigated. Photocontrol of chemical and physical functions of various supramolecular systems has vigorously been studied by using photochemical configurational change of azobenzene derivatives.[22,23]... 

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