Английская Википедия:Benzenediazonium tetrafluoroborate
Шаблон:Short description Шаблон:Chembox
Benzenediazonium tetrafluoroborate is an organic compound with the formula [C6H5N2]BF4. It is a salt of a diazonium cation and tetrafluoroborate. It exists as a colourless solid that is soluble in polar solvents. It is the parent member of the aryldiazonium compounds,[1] which are widely used in organic chemistry.
Synthesis
Diazotization of aniline in the presence of hydrochloric acid:
- C6H5NH2 + HNO2 + HCl → [C6H5N2]Cl + 2 H2O
The tetrafluoroborate can be obtained from crude benzenediazonium chloride by salt metathesis using tetrafluoroboric acid.
- [C6H5N2]Cl + HBF4 → [C6H5N2]BF4 + HCl
The tetrafluoroborate is more stable than the chloride.[2]
Properties
Шаблон:Main The diazo group (N2) can be replaced by many other groups, usually anions, giving a variety of substituted phenyl derivatives:
- C6H5N2+ + Nu− → C6H5Nu + N2
These transformations are associated with many named reactions including the Schiemann reaction, Sandmeyer reaction, and Gomberg-Bachmann reaction. A wide range of groups that can be used to replace N2 including halide, SH−, CO2H−, OH−. Of considerable practical value in the dye industry are the diazo coupling reactions.
The reaction of phenyldiazonium salts with aniline gives 1,3-diphenyltriazene.[3]
The structure of the salt has been verified by X-ray crystallography. The N-N bond distance is 1.083(3) Å.[4]
Safety
Whereas the chloride salt is explosive,[5] the tetrafluoroborate is readily isolated.
References
