Azides chelating

Pandurangi, R.S. et al. (1997a) Recent trends in the evaluation of photochemical insertion characteristics of heterobifuncdonal perfluoroaryl azide chelating agents Biochemical implications in nuclear medicine. Photochem. Photobiol. 65(2), 208-221. 

Jacobsen and co-workers have used similar catalysts in the enantioselective opening of epoxide rings. Stereospecific hydrolysis with a cobalt acetate chelate can be used to resolve racemic epoxides.97 Propylene oxide was opened with trimethylsilylazide in the presence of a 7 7 chromium azide chelate catalyst to produce (5)-l-azido-2-trimethyl-siloxypropane in quantitative yield with 97% ee.98 Cyclohexene oxide was opened with benzoic acid in the presence of 1 mol% cobalt chelate catalyst to give the hydroxyben-zoate in 98% yield with 77% ee.99... 

R.S. Pandurangi, S.R. Karra, R.R. Kimtz, W.A. Volkert, Recent Trends in the Evaluation of Photochemical Insertion Characteristics of Heterobifunctional Perfluoroaryl Azide Chelating Agents Biochemical Implications in Nuclear Medicine, Photochem. Photohiol., 1997, 65, 208-221. 

Treatment via chelation has been observed for 2-acetylpyridine thiosemi-carbazone derivatives, which have been found to possess inhibitory activity for the RNA-polymerases of the influenza virus [133]. The iron(III) complexes were shown to be 3 to 6 times more active as inhibitors of partially purified ribonucleotide reductase (no added iron) compared to uncomplexed thiosemi-carbazone [128]. Raina and Srivastava [134] prepared and characterized low spin iron(III) complexes of 2-acetylpyridine thiosemicarbazone, [Fe(8-H)2A] (A = NO3, OH, Cl, N3, NCS or NO2), which were proposed as being seven-coordinate. However, all but the azide complex are 1 1 electrolytes in DMF and their solid ESR spectra are rhombic with the g-values being about 2.20,2.15 and 2.00. Of the six complexes, the azide ion seems to interact ihost strongly with the iron(III) center. 

Strategy has also been applied to the synthesis of the azide and dimethylamide chelate complexes (Scheme 37). The latter salt is not stable and undergoes elimination of triphenylmethane to produce a H2C = NMe adduct of 17. In this adduct, the imine interacts only with one boron center. 

Several types of corrosion inhibitors have been investigated in the last 20 years [53-55] these include calcium and sodium nitrites, sodium benzoate, sodium/potassium chromate, sodium salts of silicates and phosphates, stannous chloride, hydrazine hydrate, sodium fluorophosphate, permanganate, aniline and related compounds, alkalis, azides, ferrocyanide, EDTA and many chelating compounds. However, in terms of field practice and research data, nitrite-based compounds occupy a dominant position. 

In the square pyramidal complex [Ni(Me4cyclam)N3](C104) (379) (Me4cyclam is 1,4,8,11-tetramethylT,4,8,ll-tetraazacyclotetradecane) the coordinated azide anion is on the same side of the four methyl groups with the nickel atom 33 pm from the N4 plane. The five- and six-membered chelate rings are in the usual gauche and chair conformations respectively.2681 This complex is labile in comparison with the very inert dinuclear complex... 

R CO-5-R-ttaH) tetrazoles, respectively (114). The azide Pd(N3)2-(PPh3)2 also undergoes 1,3-cycloaddition reactions with organic isonitriles (RNC) (15) and isothiocyanates (RNCS) (114) to afford the complexes 42 and 43 (M = Pd), respectively. N-l-Coordinated tetrazolate chelate complexes 44 and 45 are formed by treatment of... 

As expected, azide addition to dimethyl maleate is very sluggish, and a triazoline is not isolated32 because the LUMOfumarale < LUMOmaleale.304a Recently, however, it has been found that azide coordinated in a cobalt chelate complex [N3Co(DH)2NH3] is sufficiently reactive to add to diethyl maleate, and 25% of the pure triazoline has been obtained (Scheme 80).30 5... 

Cesium antimony (III) chloride, 3CsCl-2SbCls, precipitation in extraction of cesium from pollucite, 4 6 Cesium azide, 1 79 Cesium dibromoiodate(I), 5 174 Cesium dichloroiodate(I)(iodo-dichloride), 4 9 5 174 analysis of, 4 11 Cesium diiodoiodate(I), 5 174 Cesium nitrate, 4 6 1-hydrogen nitrate, 4 7 Cesium titanium alum, 6 50 Charcoal, sugar, 2 74 Chelate compounds, of 1,3-diketones, 2 11 5 105 of o-hydroxyaldehydes and o-hy-droxyphenones, 2 11... 

An osmium(VI) nitrido complex with tetraanionic chelating amide ligand was prepared by the reaction of [Os(T 4-HBA-B)(PPh3)2] with phenyl azide in benzene at room temperature. The X-ray structure of [Osvi(N)(t)4-HBA-B)]- revealed a square-pyramidal structure with a measured Os=N distance of 1.64(1) A (282). 

Plant use of iron depends on the plant s ability to respond chemically to iron stress. This response causes the roots to release H+ and deduct ants, to reduce Fe3+, and to accumulate citrate, making iron available to the plant. Reduction sites are principally in the young lateral roots. Azide, arsenate, zinc, copper, and chelating agents may interfere with use of iron. Chemical reactions induced by iron stress affect nitrate reductase activity, use of iron from Fe3+ phosphate and Fe3+ chelate, and tolerance of plants to heavy metals. The iron stress-response mechanism is adaptive and genetically controlled, making it possible to tailor plants to grow under conditions of iron stress. 

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