|Molar mass||112.17 g·mol−1|
|Appearance||White crystalline powder|
|Melting point||156 °C (313 °F; 429 K)|
|Boiling point||174 °C (345 °F; 447 K)|
|Acidity (pKa)||3.0, 8.8 (in water)|
|H228, H302, H315, H319, H335, H412|
|P210, P261, P273, P305 + P351 + P338|
|R-phrases||R11, R22, R36/37/38, R52/53|
|Flash point||62 °C (144 °F; 335 K)|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
DABCO or 1,4-diazabicyclo[2.2.2]octane is a chemical compound and a registered trademark for Air Products' catalyst product line including 1,4-diazabicyclo[2.2.2]octane. It is a polyurethane catalyst, Baylis-Hillman reaction catalyst, complexing ligand, and Lewis base. It is used to regulate the reaction rate in Flexplay time-limited DVDs by adjusting pH. Antioxidants, like DABCO, are used to improve the lifetime of dyes. This makes DABCO useful in dye lasers and in mounting samples for fluorescence microscopy (when used with glycerol and PBS). DABCO can also be used to demethylate quaternary ammonium salts by heating in dimethylformamide (DMF).
Although the first pKa is 8.8 that is almost the same as ordinary alkylamines, the nucleophilicity is high because the alkyl groups does not disturb the lone pairs.
DABCO has been used as a catalyst for a metal-free Sonogashira coupling, with or without microwave enhancement. For example, phenylacetylene couples with electron-deficient iodoarenes to furnish the Sonogashira product in 77% yield with 95% selectivity.
- D. H. Ripin, D. A. Evans (2002). "pKa's of Nitrogen Acids" (PDF).
- "Safety data for 1,4-diazabicyclo[2.2.2]octane (see MSDS)". Sigma-Aldrich.
- Cecchi, L.; DeSarlo, F.; Machetti, F. (2006). "1,4-Diazabicyclo[2.2.2]octane (DABCO) as an Efficient Reagent for the Synthesis of Isoxazole Derivatives from Primary Nitro Compounds and Dipolarophiles: The Role of the Base". European Journal of Organic Chemistry 2006 (21): 4852–4860. doi:10.1002/ejoc.200600475.
- Valnes, K.; Brandtzaeg, P. (1985). "Retardation of immunofluorescence fading during microscopy" (PDF). Journal of Histochemistry and Cytochemistry 33 (8): 755–761. PMID 3926864.
- Ho, T. L. (1972). "Dealkylation of Quaternary Ammonium Salts with 1,4-Diazabicyclo[2.2.2]octane". Synthesis 1972 (12): 702. doi:10.1055/s-1972-21977.
- Luque, R.; Macquarrie, D. J. (2009). "Efficient solvent- and metal-free Sonogashira protocol catalysed by 1,4-diazabicyclo(2.2.2) octane (DABCO)". Organic and Biomolecular Chemistry 7 (8): 1627–1632. doi:10.1039/b821134p. PMID 19343249.
- Baylis, A. B.; Hillman, M. E. D. German Patent 2155113, 1972.