View source for 3,3'-Diaminobenzidine

{{chembox
|   Name = 3,3'-Diaminobenzidine
|   ImageFile = 3,3'-Diaminobenzidine.svg
|   ImageSize = 200px
|   ImageName = 3,3'-Diaminobenzidine
|   IUPACName = 3,3',4,4'-Tetraamino-diphenyl
| Section1 = {{Chembox Identifiers
|  CASNo = 91-95-2
|   CASOther = <br>[7411-49-6] (4HCl)
|   SMILES = 
|   RTECS = DV8750000<br>DV8753000 (4HCl)
|   ECNo = 202-110-6
  }}
| Section2 = {{Chembox Properties
|   Formula = C<sub>12</sub>H<sub>14</sub>N<sub>4</sub><br>C<sub>12</sub>H<sub>18</sub>Cl<sub>4</sub>N<sub>4</sub> (4HCl)
|   MolarMass = 214.27 g/mol<br>360.11 g/mol (4HCl)
|   Density =
|   MeltingPt = 175&ndash;177 °C<br>280 °C (4HCl.2H<sub>2</sub>O)
|   BoilingPt =
  }}
| Section7 = {{Chembox Hazards
|   ExternalMSDS =[http://physchem.ox.ac.uk/MSDS/DI/3,3'-diaminobenzidine.html External MSDS]
|   EUClass = Harmful ('''Xn''')
|   FlashPt =
|   RSPhrases = {{R20}} {{R21}} {{R22}} {{R40}}
|   SPhrases = {{S36}} {{S37}} {{S45}}
|   NFPA-H = 2 | NFPA-F = 1 | NFPA-R = 2
|   LD50 = mouse, oral Acute: 1834 mg/kg.
  }}
}}

'''3,3'-Diaminobenzidine''' (DAB) is an [[organic compound]]. This derivative of [[benzidine]] is a precursor to [[polybenzimidazole fiber]]<ref name=Ullmann>Hans Schwenecke, Dieter Mayer “Benzidine and Benzidine Derivatives” in Ullmann’s Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim.</ref>.  As its water-soluble [[hydrochloride|tetrahydrochloride]], it has been used in [[immunohistochemical staining]] of [[nucleic acid]]s and [[proteins]].{{Fact|date=November 2007}}

==Preparation==
Diaminobenzidine, which is commercially available, is prepared by reacting [[3,3'-dichlorobenzidine]] and [[ammonia]] with a copper catalyst at high temperature and pressure, followed by acidic [[Workup (chemistry)|workup]].<ref>{{Ref patent
 |country= US
 |number=3943175
 |status=
 |title=Synthesis of pure 3,3'-diaminobenzidine
 |pubdate=
 |gdate=1976-03-09
 |fdate=
 |pridate=
 |invent1=Druin, Melvin L.
 |invent2=Oringer, Kenneth
 |assign1=Celanese Corporation
 |assign2=
 |class=564/309 
}}</ref>

==Applications==
Diaminobenzidine is oxidized by [[hydrogen peroxide]] in the presence of [[hemoglobin]] to give a dark brown color. This is used to detect fingerprints in blood.<ref>{{cite web | title = D.A.B. (Diaminobenzidine) | publisher = Chesapeake Bay Division, International Association for Identification | url = http://www.cbdiai.org/Reagents/dab.html | accessdate = 2007-11-09}}</ref> Improperly prepared tissue samples may give false positives<ref>{{cite web
| accessdate=2008-02-02
| url=http://www.dako.co.uk/prod_downloadpackageinsert.pdf?objectid=105426004
| format=pdf
| title=Liquid DAB Substrate
| publisher=Dako
}}</ref>
In neuroscience, this reaction is used to stain neurons which were prepared to contain hydrogen peroxidase, using complexes of injected [[biocytin]] with avidine or streptavidine, biotin, and the peroxidase.

==References==
{{reflist}}

==External links==
* [https://fscimage.fishersci.com/msds/65650.htm Fishersci.com]
* [http://www.polysciences.com/shop/product.asp?pf_id=04008&dept_id=1025 Polysciences.com]

{{DEFAULTSORT:Diaminobenzidine, 3,3'-}}
[[Category:Aromatic amines]]

[[ru:3,3'-диаминобензидин]]
[[Category:2Fix]]