1,2-Difluorobenzene, also known as DFB, is an aromatic compound with formula C₆H₄F₂. This colorless liquid is a solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 used in the electrochemical studies of transition metal complexes.

Synthesis

1,2-Difluorobenzene is prepared by a simple substitution reaction of fluorine

Fluorine

Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

 with fluorobenzene

Fluorobenzene

Fluorobenzene is the chemical compound with the formula C6H5F, often abbreviated PhF. This species is a derivative of benzene, with a single fluorine atom attached. Its melting point is 44 °C lower than that of benzene, indicative of the remarkable effect of fluorination on the intermolecular...

.

C₆H₅F + F₂ → C₆H₄F₂ + HF

The 1,4-isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

 and small amounts of the 1,3-isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

 are also produced in the reaction as the fluorine group on the aromatic ring of fluorobenzene

Fluorobenzene

Fluorobenzene is the chemical compound with the formula C6H5F, often abbreviated PhF. This species is a derivative of benzene, with a single fluorine atom attached. Its melting point is 44 °C lower than that of benzene, indicative of the remarkable effect of fluorination on the intermolecular...

 is ortho- and para- directing.

Applications

1,2-Difluorobenzene has been used as solvent for the electrochemical analysis of transition metal complexes. It is relatively chemically inert, non-coordinating, and has a dielectric constant high enough to dissolve many electrolytes and metal complex salts. It is used instead of the common solvents for metal complexes acetonitrile

Acetonitrile

Acetonitrile is the chemical compound with formula . This colourless liquid is the simplest organic nitrile. It is produced mainly as a byproduct of acrylonitrile manufacture...

, DMSO

Dimethyl sulfoxide

Dimethyl sulfoxide is an organosulfur compound with the formula 2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water...

, and DMF

Dimethylformamide

Dimethylformamide is an organic compound with the formula 2NCH. Commonly abbreviated as DMF , this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions...

because they can be coordinating.