Azide 248135 220218071 2008-06-18T20:36:02Z ChemNerd 2246483 formatting references {{Double image stack|right|Azid-Ion.svg|Azide-2D.png |200|The azide anion|The azide functional group}} '''Azide''' is the anion with the formula N<sub>3</sub><sup>−</sup>. It is the [[conjugate base]] of [[hydrazoic acid]]. N<sub>3</sub><sup>−</sup> is a linear anion that is [[isoelectronic]] with [[carbon dioxide|CO<sub>2</sub>]] and [[nitrous oxide|N<sub>2</sub>O]]. Per [[valence bond theory]], azide can be described by several resonance structures, an important one being <big>N<sup>−</sup>=N<sup>+</sup>=N<sup>−</sup></big>. Azide is also a [[functional group]] in [[organic chemistry]], RN<sub>3</sub>.<ref>'''Review:''' S. Bräse, C. Gil, K. Knepper, V. Zimmermann, Angew. Chem. 2005, 117, 5320-5374; Angew. Chem. Int. Ed. 2005, 44, 5188-5240.</ref> ==Inorganic azides== Azide forms both covalent and ionic compounds with metals. [[Sodium azide]], NaN<sub>3</sub>, is a salt that is widely used as the propellant in [[airbag]]s. Covalent azides are numerous,<ref>Tornieporth-Oetting, I. C.; Klapoetke, T. M. "Covalent Inorganic Azides" Angewandte Chemie, International Edition in English (1995), volume 34, pages 511-20. AN 1995:483017</ref> an example being [Co(NH<sub>3</sub>)<sub>5</sub>N<sub>3</sub>]Cl<sub>2</sub>, in which it is a monodentate [[ligand]] in a [[complex (chemistry)|coordination complex]] of Co<sup>3+</sup>. A metal-organic azide is [[trimethylsilyl]]azide, which is sometimes used as an anhydrous source of N<sub>3</sub><sup>−</sup>. ==Azides in biochemistry== The azide anion is toxic, inhibiting the function of [[cytochrome c oxidase]] by binding irreversibly to the heme cofactor, in a process similar to that of [[cyanide]]. Azide salts are also used in studies of [[mutagenesis]]. == Organic azides==<!-- This section is linked from [[Organic reaction]] --> Organic azides engage in useful [[organic reactions]]. The terminal nitrogen is mildly nucleophilic. Azides easily extrude diatomic [[nitrogen]], a tendency that is exploited in many reactions such as the [[Staudinger Ligation]] or the [[Curtius rearrangement]] or for example in the synthesis of γ-imino-β-enamino esters.<ref>''An efficient synthesis of γ-imino- and γ-amino-β-enamino esters'' Mangelinckx, S.; Van Vooren, P.; De Clerck, D.; Fülöp, F.; De Kimpea, N. [[Arkivoc]] JC-1560E '''2005''' [http://www.arkat-usa.org/ark/journal/2006/I03_Coxon/1560/JC-1560E.asp Online Article]</ref> <ref>Reaction conditions: a) [[sodium azide]] 4 eq., [[acetone]], 18 [[hour|hrs]] [[reflux]] 92% [[chemical yield]] b) [[amine|isopropyl amine]], [[titanium tetrachloride]], [[diethyl ether]] 14 hr reflux 83% yield. Azide '''2''' is formed in a [[nucleophilic aliphatic substitution]] reaction displacing chlorine in '''1''' by the azide anion. The [[ketone]] reacts with the [[amine]] to an [[imine]] which [[tautomer]]izes to the [[enamine]] in '''4'''. In the next [[rearrangement reaction]] nitrogen is expulsed and a proton transferred to '''6'''. The last step is another tautomerization with the formation of the enamine '''7''' as a mixture of cis and [[trans isomer]]s</ref> [[Image:Iminoenaminoester.gif|center|γ-imino-β-enamino esters from azides]] In the [[azide alkyne Huisgen cycloaddition]], organic azides react as [[1,3-dipole]]s. Examples of organic azides are the chemical reagent [[phenyl azide]] and the antiviral drug [[zidovudine]] (AZT). Another azide regular is [[tosyl azide]] here in reaction with [[norbornadiene]] in a nitrogen insertion reaction:<ref>''A Facile Synthesis of a Polyhydroxylated 2-Azabicyclo[3.2.1]octane'' Damon D. Reed and Stephen C. Bergmeier ''[[J. Org. Chem.]]''; '''2007'''; 72(3) pp 1024 - 1026; (Note) {{DOI|10.1021/jo0619231}}</ref> [[Image:Azidenorbornadieneinsertion.png|center|400px|Norbornadiene reaction with tosyl azide]] ==Dutt-Wormall reaction== A classic method for the synthesis of azides is the '''Dutt-Wormall reaction''' <ref>''CCXLI.—The action of diazo-salts on aromatic sulphonamides. Part I'' Pavitra Kumar Dutt, Hugh Robinson Whitehead and Arthur Wormall, J. Chem. Soc., Trans., '''1921''', 119, 2088 {{DOI|10.1039/CT9211902088}}</ref> in which a [[diazonium salt]] reacts with a [[sulfonamide]] first to a diazoaminosulfinate and then on [[hydrolysis]] the azide and a [[sulfinic acid]].<ref>''Name Reactions: A Collection of Detailed Reaction Mechanisms'' By Jie Jack Li Published '''2003''' Springer ISBN 3540402039</ref> ==Safety== * [[Sodium azide]] is toxic ([[LD50|LD<sub>50</sub>]] oral (rats) = 27 mg/kg) and can be absorbed through the skin. * [[Heavy metals|Heavy metal]] azides, such as [[lead azide]] are very unstable [[primary explosives|primary]] [[high explosive]]s [[detonation|detonable]] when heated or shaken. * Sodium azide decomposes explosively upon heating to above 275 °C. * Sodium azide reacts vigorously with [[carbon disulfide|CS<sub>2</sub>]], [[bromine]], [[nitric acid]], [[dimethyl sulfate]], and a series of heavy metals, including [[copper]] and [[lead]]. * In reaction with water or [[Brønsted acid]]s the highly toxic and explosive [[hydrogen azide]] is released. * It has been reported that sodium azide and polymer-bound azide reagents react with [[dichloromethane]] and [[chloroform]] to form di- and triazidomethane resp., which are both unstable in high concentrations in solution. Various devastating explosions were reported while reaction mixtures were being concentrated on a rotary evaporator. The hazards of diazidomethane (and triazidomethane) have been well documented.<ref>A. Hassner et al., ''Angew. Chem. Int. Ed. Engl.'', 25, 479 (1986), ''J. Org. Chem.'', 55, 2304 (1990).</ref> * Heavy-metal azides that are highly explosive under pressure or shock are formed when solutions of sodium azide or HN<sub>3</sub> vapors come into contact with heavy metals or their salts. Heavy-metal azides can accumulate under certain circumstances, for example, in metal pipelines and on the metal components of diverse equipment ([[rotary evaporator]]s, [[freeze drying|freezedrying]] equipment, cooling traps, water baths, waste pipes), and thus lead to violent explosions. Some organic and other covalent azides are classified as highly explosive and toxic (inorganic azides as neurotoxins; azide ions as [[cytochrome c oxidase]] (COX) inhibitors). * Solid iodoazide is explosive and should not be prepared in the absence of solvent.<ref>L. Marinescu, J. Thinggaard, I. B. Thomsen, M. Bols, ''J. Org. Chem''. 2003, 68, 9453 – 9455.</ref> == References == {{Reflist}} ==External links== * [http://organic-chemistry.org/synthesis/C1N/azides/index.shtm Synthesis of organic azides], recent methods * [http://www.ehs.ucsb.edu/units/labsfty/labrsc/factsheets/Azides_FS26.pdf Synthesizing, Purifying, and Handling Organic Azides] * [http://pubs.acs.org/cgi-bin/abstract.cgi/joceah/asap/abs/jo070162e.html Preparation of Polyfunctional Acyl Azides] * [http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/azide.rxns.html Synthesis and Reduction of Azides] [[Category:Functional groups]] [[Category:Azides| ]] [[bg:Азид]] [[de:Azide]] [[es:Azida]] [[fr:Azoture]] [[hr:Azidi]] [[it:Azide]] [[nl:Azide]] [[ja:アジ化物]] [[pl:Azydek]] [[ru:Азиды]] [[sv:Azidgrupp]] [[uk:Азиди]] [[zh:叠氮化合物]]