Hydrazoic acid metal complexes

Hydrazine, bis(allylthiocarbamido)-in gravimetry, 1, 534 liquid-liquid extraction, 1,546 Hydrazines, 2, 101 macrocyclic synthesis, 2,904 metal complexes, 2, 30 in plutonium extraction, 6, 948 Hydrazoic acid... 

In summary, aqueous hydrazoic acid solutions up to 1 molar are conveniently made by cation exchange and are obtained chemically pure from anion pure (nitrate) sodium azide and a prepurified resin. Purification of the latter by washing the heavy metals out as chloro complexes is simple in principle, but time-consuming. For projects requiring numerous hydrazoic acid batches the approach has its advantages, but for single preparations distillation methods are preferable. 

Hydrazoic acid (HN3) is another member of the set of 16 valence electron 1,3 dipoles. As with both NNO and HCNO, HNNN has a hypervalent central nitrogen atom that is both doubly and triply bound to its neighbouring atoms. The calculated properties of the neutral, protonated and metal ion complexed hydrazoic acid are tabulated in Tables 2, 3 and 33-36. The photochemistry and detonation properties of HN3 have been of particular interest. 

No phosphorus analogues of multiply bonded nitrogen species such as diazene, HN=NH, tetra-zene, H2N-N=N-NH2, and hydrazoic acid, HN3 have been isolated. Diphosphene, HP=PH, appears to have been detected spectroscopically [9,10], and some metal complexes have been made (8.262). Various organic derivatives RP=PR have been synthesised (Chapter 6.19), however, and the PH molecule has been studied spectroscopically [11]. Metallo derivatives of H2P-P=P-PH2 are known (Chapter 8). 

Knauss, 1970), and hydrazoic acid (Conner and Jones, 1971b) react with metal-carbene complexes to give cleavage products. 

Metal salts of hydrazoic acid from lead, silver, mercury, copper and other heavy metals are very sensitive to mechanical stimulus and explode easily. Heating of these metal azides causes stroug explosions. Table 1.1 suuunarizes some deflagration temperatures of well-known metal azides that decompose explosively when small samples embedded within a metal sleeve are dipped into a hot Wood metal bath. Although these temperatures are relatively high other new metal azide complexes might explode at much lower temperatures. 

The rapid reaction of the aquopenta-ammineruthenium(n) cation with hydrazoic add yields NH3, Ng, and ruthenium(iii) complexes, the ammonia produced being co-ordinated to the oxidized metal centre with the formation of [Ru(NH3)6] + compare the corresponding reaction with [Cr(H20)6] +, ref. 225. One mole of nitrogen is produced per mole of azide ion and the mechanism is considered to involve the co-ordination of the hydrazoic acid into the labile co-ordination sphere of the [Ru(NH3)5(H20)] + ion ... 

Photochemical reactions of the iridium(m) and rhodium(m) complexes [M(NH3)6(N3)] + result in the production of a co-ordinated nitrene intermediate. In concentrated hydrochloric add the iridium(m) product is [Ir(NH3)6(NH2Cl)] +, as in the equivalent thermal reaction. These iridium(ra) and rhodium(m) complexes thus behave photochemically in a similar mmmer to hydrazoic acid and to organic azides. Their behaviour contrasts with that of some other transition-metal azide complexes, e.g. those of ruthenium(n), where an azido-radical is the photochemical intermediate. One can indeed group transition-metal azide complexes into three groups, with their thermal and photochemical reactions depending on the relative ease of oxidation or reduction (or neither) of the transition-metal centre. ... 

A variety of reducing agents have been used to reduce nitroarenes to azo compounds. However, a mixture of zinc and sodium hydroxide is used most frequently. - Reduction under these conditions produces hydrazo compounds, which are then oxidized to azo compounds by dissolved atmospheric oxygen alternatively, air can be drawn through the product solution to achieve the conversion. - Occasionally, activation of the zinc dust is required prior to its use, and, since metal ions form chelated complexes with azo compounds, a vigorous post-treatment with acids is recommended. The zinc-sodium hydroxide reduction conditions are sufficiently mild that p-nitrostyrene (2 equation 2), can be reduced without reduction of the vinyl groups. ... 

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