Zinc complexes azides

The complex azide is highly explosive and must be handled with extreme care. The analogous potassium and caesium derivatives of zinc azide and nickel azide deflagrate strongly in a flame and some are shock-sensitive [1], The potassium salt alone out of 8 azido-complexes exploded during X-irradiation in an ESCA study [2],... 

Narang, K. K. et al., Synth. React, lnorg. Met.-Org. Chem., 1996, 26(4), 573 The explosive properties of a series of 5 amminecobalt(III) azides were examined in detail. Compounds were hexaamminecobalt triazide, pentaammineazidocobalt diazide, cis- and fram-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],... 

In salts of [Zn(NCS)4], the thiocyanate ligand is N-bonded, whereas it is S-bonded to cadmium in [Cd(SCN)4] salts, reflecting the respective hard and soft characters of the respective metal ions. Zinc complexes with the azide ion are well known crystallographic determinations of the structures of the compounds M2Zn(N3)4 (M = K or Cs) show the presence of discrete [Zn(N3)4] tetrahedra with linear azide groups. Some of the complexes in this category, such as those with hydrazine and azide, for example [Zn(N2H4)2(N3)2], are of interest as primary explosives and care is needed in their manipulation. The 2,2 -dipyridylamine-azide complexes [Zn(dpa)(N3)2] and [Zn(dpa)(N3)(N03)], which have infinite 2D and 3D structures respectively, display fluorescence and phosphorescence. ... 

On the other hand, thermolysis of ferrocenylsulpkonyl azide (14) in aliphatic solvents may lead to the predominant formation of the amide (16) 17>. A 48.4% yield of (16) was obtained from the thermolysis in cyclohexane while an 85.45% yield of 16 was formed in cyclohexene. Photolysis of 14 in these solvents led to lower yields of sulphonamide 32.2% in cyclohexane, 28.2% in cyclohexene. This suggests again that a metal-nitrene complex is an intermediate in the thermolysis of 14 since hydrogen-abstraction appears to be an important made of reaction for such sulphonyl nitrene-metal complexes. Thus, benzenesulphonamide was the main product (37%) in the copper-catalyzed decomposition of the azide in cyclohexane, and the yield was not decreased (in fact, it increased to 49%) in the presence of hydroquinone 34>. On the other hand, no toluene-sulphonamide was reported from the reaction of dichloramine-T and zinc in cyclohexane. 

Sulphonyl nitrene-metal complexes also undergo insertion into aliphatic C—H bonds as witnessed by the insertion into dioxan on treatment with chloramine-T and copper 45> and into cyclohexane with di-chloramine-T and zinc 44> and into cyclohexene with benzenesulphonyl azide and copper 34> and with ferrocenylsulphonyl azide 25>. 

The formation of complexes of l,2,3,4-thiatriazole-5-thiol has been well described in CHEC-II(1996) 1,2,3,4-thiatriazole-5-thiol can form complexes with various metals such as palladium, nickel, platinum, cobalt, zinc, etc. <1996CHEC-II(4)691>. These complexes can be prepared either by cycloaddition reactions of carbon disulfide with metal complexes of azide anion (Equation 20) or directly from the sodium salt of l,2,3,4-thiatriazole-5-thiol with metal salts. For instance, the palladium-thiatriazole complex 179 can be obtained as shown in Equation (20) or it may be formed from palladium(ll) nitrate, triphenylphosphine, and sodium thiatriazolate-5-thiolate. It should be noted that complexes of azide ion react with carbon disulfide much faster than sodium azide itself. 

It is this local character of vibrational dephasing that is utilized in the experiments described in this section. In these experiments, spectral diffusion of test molecules bound to enzymes has been investigated in order to study the fluctuations of the reactive sites. The local character of these interactions can be pictured in great detail since in many cases high-resolution x-ray structure of the complexes are available. One example we have studied, shown in Fig. 8, is azide bound to carbonic anhydrase (CA-N3 ) (107). Carbonic anhydrase is a zinc enzyme that catalyzes the interconversion of... 

Misunobu substitution conditions (PPh3, DIAD) have also been successfully applied to the direct displacement of hydroxyl using zinc azide-pyridine complex [83]. 

Alkyl bromides and azides. Substitution of hydroxyl groups by bromine is readily performed with PhjP and 2,4,4,6-tetrabromo-2,5-cyclohexadienone. THP ethers and many silyl ethers are also converted to bromides directly. When zinc azide dipyridine complex is also present alcohols are transformed into azides. Inversion of configuration of the carbinolic center accompanies both transformations. 

On addition of sodium azide to the zinc(II) cryptate, a solid cascade complex was isolated. Evidence of cascade formation was provided by an investigation of azide ion infrared (IR) stretching frequencies (145). 

In view of its zinc content, the activity of yeast ADH was studied in the presence of a large variety of agents known to combine with this metal ioii in simple systems as salts, chelates, or complex ions. It was expected that the formation of such compounds would reduce the activity of the enzyme if zinc were involved in its mechanism of action. In addition to OP, aa D, 8-OHQ-5SA, DZ, and TU (Vallee and Hoch, 1955), the following have since been found to inhibit yeast ADH activity NaDDC, BAL, Cupferron, thiosemicarbazide, sodium sulfide, potassium cyanide, and sodium azide (Vallee and Hoch, in preparation for publication). Inhibition was found to be strongly dependent upon the time of contact between the enzyme and the inhibitor prior to the measurement of activity, the pH of the preincubation mixture, and the temperature at which the preincubation was allowed to take place. 

Hydroxymethyl-1,4-benzodioxin (137) obtained in 80% yield by reduction of ethyl 1,4-benzo-dioxin-2-carboxylate (39) with lithium aluminum hydride in refluxing ether <91TL5525> reacted with zinc azide bis-pyridine complex under Mitsunobu conditions (triphenylphosphine, diisopropyl azodicarboxylate) to yield exclusively compound (138) in 75% yield. Otherwise, (137) was first reacted with zinc iodide under the same conditions until complete transformation of the starting material into the mixture of regioisomers (139) and (140) excess of dry piperidine was then added to the crude reaction medium to yield the alkenic analogue (141) of Piperoxan <89TL1637>. 

Nalbandyan, 1982 Hodgson and Fridovich, 1975 Asada et al., 1975), whereas azide inhibits the enzymes in the following order iron > manganese > copper/zinc superoxide dismutase (Misra and Fridovich, 1978). Diethyldithiocarbamate is another well-characterized inhibitor of the copper/zinc superoxide dismutase (Heikkila et al., 1977). It forms a complex with the copper and removes the metal from all the protein ligands. The copper-diethyldithiocarbamate complex can be separated without affecting the zinc content of the protein (Cocco et al., 1981). 

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