DABCO (1,4-diazabicyclo .2.2ctane), also known as triethylenediamine or TEDA, is a bicyclic

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

with the formula N₂(C₂H₄)₃. This colorless solid is a highly nucleophilic tertiary amine base, which is used as a catalyst and reagent in

polymerization In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many f ...

and

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

. It is similar in structure to quinuclidine, but the latter has one of the nitrogen atoms replaced by a carbon atom.

Reactions

The p''K''_a of DABCOsup>+ (the protonated derivative) is 8.8, which is almost the same as ordinary alkylamines. The nucleophilicity of the amine is high because the amine centers are unhindered. It is sufficiently basic to promote C–C coupling of terminal acetylenes, for example,

phenylacetylene Phenylacetylene is an alkyne hydrocarbon containing a phenyl group. It exists as a colorless, viscous liquid. In research, it is sometimes used as an analog for acetylene; being a liquid, it is easier to handle than acetylene gas. Preparation In ...

couples with electron-deficient iodoarenes. : DABCO Sonogashira

Catalyst

DABCO is used as a base-catalyst for: *formation of

polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane is produced from ...

from alcohol and isocyanate functionalized monomers and pre-polymers. * Baylis-Hillman reactions of aldehydes and unsaturated ketones and aldehydes. : Baylis Hilman Reaction Scheme

Lewis base

As an unhindered amine, it is a strong

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elect ...

and

Lewis base A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...

. It forms a crystalline 2:1 adduct with

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3 ...

and

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic a ...

Quencher of singlet oxygen

DABCO and related amines are quenchers of singlet oxygen and effective antioxidants, and can be used to improve the lifetime of

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

s. This makes DABCO useful in

dye laser A dye laser is a laser that uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths, often spanning 50 to 100 ...

s and in mounting samples for fluorescence microscopy (when used with

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

and PBS). DABCO can also be used to demethylate

quaternary ammonium salt In chemistry, quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure , R being an alkyl group or an aryl group. Unlike the ammonium ion () and the primary, secondary, or tertiary ammonium cation ...

s by heating in

dimethylformamide Dimethylformamide is an organic compound with the formula ( CH3)2NC(O)H. Commonly abbreviated as DMF (although this initialism is sometimes used for dimethylfuran, or dimethyl fumarate), this colourless liquid is miscible with water and the majo ...

(DMF).

Production

It is produced by thermal reactions of compounds of the type H₂NCH₂CH₂X (X = OH, NH₂, or NHR) in the presence of zeolitic catalysts. An idealized conversion is shown for the conversion from ethanolamine: :3 H₂NCH₂CH₂OH → N(CH₂CH₂)₃N + NH₃ + 3 H₂O

Uses

In chemical and biological defense,

activated carbon Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that increase the surface area availa ...

is impregnated with DABCO for use in filters for masks, collective protection systems, and the like.