|Preferred IUPAC name
[1,1'-Biphenyl]-3,3',4,4'-tetraamine (not recommended)
3D model (Jmol)
|Molar mass||214.27 g/mol
360.11 g/mol (4HCl)
|Melting point||175 to 177 °C (347 to 351 °F; 448 to 450 K) (280 °C for 4HCl.2H2O)|
|Safety data sheet||External MSDS|
EU classification (DSD)
|S-phrases||S36 S37 S45|
|R/S statement||R20 R21 R22 R40|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|mouse, oral Acute: 1834 mg/kg.|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
3,3'-Diaminobenzidine (DAB) is an organic compound that is both chemically and thermodynamically stable. This derivative of benzidine is a precursor to polybenzimidazole fiber. This fiber can be used to construct materials that are resistant to chemicals and high temperature. Fabrics made from these fibers do not melt when exposed to flame and do not burn. As its water-soluble tetrahydrochloride, DAB has been used in immunohistochemical staining of nucleic acids and proteins.
DAB is symmetric about the central carbon bond between both ring structures. In the crystal, the rings of each molecule are co-planar and the amine units connect molecules to form an intermolecular 3-dimensional hydrogen bond network.
- (NH2)C6H4C6H4(NH2) + 2(CH3CO)2O ⟶ (NHCOCH3)C6H4C6H4(NHCOCH3) + 2CH3CO2H
- (NHCOCH3)C6H4C6H4(NHCOCH3) + 2HNO3 ⟶ (O2N)(NHCOCH3)C6H3C6H3(NHCOCH3)(NO2) + 2H2O
- (O2N)(NHCOCH3)C6H3C6H3(NHCOCH3)(NO2) + 2NaOH ⟶ (O2N)(NH2)C6H3C6H3(NH2)(NO2) + 2(NaOCOCH3)
- 3(O2N)(NH2)C6H3C6H3(NH2)(NO2) + 12HCl + 10Fe0 ⟶ 3(NH2)2C6H3C6H3(NH2)2 + 4Fe2O3 + 6FeCl2
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. The solubility of DAB in water allows for adaptability compared to other detection solutions which use toxic solvents. Improperly prepared tissue samples may give false positives In research, this reaction is used to stain cells that were prepared with hydrogen peroxidase enzyme, following common immunocytochemistry protocols. In research being done on Alzheimer's disease, Aβ protein amyloid plaques are targeted by a primary antibody, and subsequently by a secondary antibody, which is conjugated with a peroxidase enzyme. This will bind DAB as a substrate and oxidize it, producing an easily observable brown color. Plaques can then be quantified for further evaluation. One other method uses complexes of injected biocytin with avidin or streptavidin, biotin, and then peroxidase.
- Hans Schwenecke, Dieter Mayer "Benzidine and Benzidine Derivatives" in Ullmann’s Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim.
- Roschzttardtz, H.; Grillet, L.; Isaure, M.-P.; Conejero, G.; Ortega, R.; Curie, C.; Mari, S. (2011), "The Plant Cell Nucleolus as a Hot Spot for Iron", The Journal of Biological Chemistry, 286 (32): 27863–27866, doi:10.1074/jbc.C111.269720, PMC , PMID 21719700
- Hui-Fen Qian & Wei Huang (2010). "Biphenyl-3,3',4,4'-tetraamine". Acta Crystallographica. E66 (5): o1060. doi:10.1107/S1600536810012511. PMC . PMID 21579117.
- US 3943175, Druin, Melvin L. & Oringer, Kenneth, "Synthesis of pure 3,3'-diaminobenzidine", issued 1976-03-09, assigned to Celanese Corporation
- "D.A.B. (Diaminobenzidine)". Chesapeake Bay Division, International Association for Identification. Archived from the original on 23 December 2007. Retrieved 2007-11-09.
- Sahs P (1992), "DAB: An Advancement in Blood Print Detection", J. Forensic Ident., 42: 412–420
- "Liquid DAB Substrate" (pdf). Dako. Retrieved 2008-02-02.
- Falangola, M. F.; Lee, S. P.; Nixon, R. A.; Duff, K. & Helpern, J.K. (2005). "Histological co-localization of iron in Abeta plaques of PS/APP transgenic mice". Neurochemical Research. 30 (2): 201–205. doi:10.1007/s11064-004-2442-x. PMC . PMID 15895823.