Photodecomposed product

In 500 ml of benzene, 0.5g of azide compound was solved. In a flask equipped with UV light source, the azide in benzene was photodecomposed passing nitrogens gass. The photodecomposed products were separated by column chromatography with developement... 

Pig. 2 shows the Infrared spectra of 2-phenylamino-5-azidobenzoic acid III and the photodecomposed product in KBr tablet by UV irradiation. 

Phenylamino-5-azidobenzoic acid IH was photo-decomposed in benzene without oxygen, and then the photodecomposed products were separated by column chromatography. Pig. 3 shows the Infrared spectrum of the photodecomposed component obtained from the developed layer of the column. 

The same tendency was observed in the cases of stylene,stilbene( 6) and cinnamoyloxy group( 6). The calculated value of Ti is 21700 cm". The So-)Ti absorption spectrum in EtI gives only tail near the calculated value. The emission spectrum in EPA gave such a phosphorescence as was shown in Fig.3. The Intensity Increases with the irradiation time. Therefore, it is clear that the emission spectrum is that of the photodecomposed product, which is estimated to be aniline from the similarity of the phosphorescence of the authentic sample. 

Hb and Ni-reconstituted Hb were prepared according to reported methods (13). Mb was made by the method of Alston and Storm (14) Solutions of the proteins in 0.05 M phosphate buffer at pH 7.5 were used for obtaining spectra. The proteins are stable in air and do not photodecompose. Ni protoporphyrin IX (Ni(ProtoP)), Ni uroporphyrin I (Ni(UroP)), and Ni octaethylporphyrin (Ni(OEP)) were obtained from Porphyrin Products and used without further purification. All solvents were of highest purity obtainable from commercial sources. All materials showed the literature uv-visible absorption spectra. Absorption spectra were obtained on a Perkin-Elmer Model 330 spectrophotometer. 

The dimer of CH3NO was observed early by Thompson and Linnett.419 They photodecomposed Hg(CH3)2 with 2537-A radiation in the presence of NO at 17°C. A white solid was found as a product. 

The explosive properties of a series of 5 amminecobalt(III) azides were examined in detail. Compounds were hexaamminecobalt triazide, pentaammineazidocobalt diazide, cis- and traw.v-tetraamminediazidocobalt azide, triamminecobalt triazide [1], A variety of hydrazine complexed azides and chloroazides of divalent metals have been prepared. Those of iron, manganese and copper could not be isolated cobalt, nickel, cadmium and zinc gave products stable at room temperature but more or less explosive on heating [2]. Some polyammine azido-metal nitrates of Cr, Ni and Cu were found to be explosively photosensitive. Replacement of ammonia by triethanolamine gave compounds smoothly photodecomposing [3]. 

However, flash photolysis experiments suggest that NO3- photodecomposes forming the oxide radical, O -, and O atoms via parallel primary processes (Equations 6.92 and 6.93)48 All the other products such as NO- and 02 are the products of secondary reactions. It can be seen that in the confirmation of the transient products in reactions such as those shown in Equations 6.89-6.95, flash photolysis plays a fundamental role. 

Benzyltriphenylphosphonium chloride photodecomposes to yield radical products [153], while the corresponding tetrafluoroborate gives both radical products and an ionic product (the A-benzylacetamide in acetonitrile) the last type of compounds predominates with most of the substituted benzyl derivatives studied, except with 3- and 4-methoxy, while only radical products were formed upon triplet sensitization [154]. The 4-cyanobenzylphosphonium salt gave only radicalic products [155], but... 

Early studies have shown that cyclobutanone photodecomposes to give two distinct pairs of products by C2 and C3 pathways, and new insight to its transformation mechanism became known recently. 

Compounds I and III at 313 and 238-265 nm photodecompose efficiently to CO and hydrocarbon products (i.e., co = 0.77 and 0.87, respectively). In contrast, compounds II and IV photode-composed much less efficiently under identical conditions. However, compound II photoisomerized efficiently to 3-methyl-2-cyclopentenone. This rearrangement is comparable to the photoisomerization of methylcyclopropyl ketone to methylpropenyl ketone (190). 

The pharmacodynamically active molecular structure of the calcium channel blocker, nifedipine, is photodecomposed by UV-VIS radiation (8). This effect is manifested by a change in color (from yellow to colorless) or the fading of colored preparations, formation of precipitation and alteration of the taste of the product. Such changes during storage may give patients the sense of uneasiness, confusion, and doubt as to the safety and efficacy of the product. 

Fig. 1 shows the spectral sensitivities of these azide compounds. The mechanism of the color reaction is not clear, but it is assumed that the various reaction products of nitrenes from photodecomposed azide compounds produce the mixed coloring matter. 

Wavelengths longer than 220 nm. The absence (2) of fluorescenci or phosphorescence in carbon suboxide excited in the ultraviolet would suggest that it is efficiently photodecomposed in this region of the spectrum. From its structural similarity to ketene, it is expected that this will involve production of C2O in step 1. The work of Bayes has in fact shown that this is the most probable process in the absorption region with a maximum at 265 nm. Bayes (11) found that photolysis of 02/02 mixtures led to production of allene rather than the acetylene, which is known (12) to be formed by insertion of carbon atoms into C2H. ... 

Laser flash photolysis has, as usual, illuminated the problem. Jones and Rettig photodecomposed 9-diazofluorene (188) in hexafluorobenzene and cw-4-methyl-2-pentene mixtures, and showed that the degree of stereoselectivity in the cyclopropane products depended on the concentration of the alkene. Laser flash photolysis showed that the first detectable intermediate in the photolysis reaction is the triplet carbene, and suggests that the product studies are consistent with initial formation of a singlet fluorenylidene which has an extremely short life (less than 5 ns) before forming the triplet. The singlet can be trapped only by high alkene concentrations while the more stable triplet is easily trapped. 

---