4,4'-Bipyridine

4,4′-Bipyridine is an organic compound with the formula. It is one of several isomers of bipyridine. It is a colorless solid that is soluble in organic solvents. is mainly used as a precursor to N,''N''′-dimethyl-4,4′-bipyridinium ²⁺, known as paraquat.

History

4,4′-Bipyridine was first obtained in 1868 by the Scottish chemist Thomas Anderson via heating pyridine with sodium metal. However, Anderson's empirical formula for 4,4′-bipyridine was incorrect. The correct empirical formula, and the correct molecular structure, for 4,4′-bipyridine was provided in 1882 by the Austrian chemist Hugo Weidel and his student M. Russo.

Uses

4,4'-Bipyridine is an intermediate in the production of paraquat, a widely used herbicide. In this process, pyridine is oxidized to 4,4'-bipyridine in a coupling reaction, followed by dimethylation to form paraquat.

Reactions

The reducing agent N,N'-bis-4,4'-bipyridinylidene is produced by reduction of 4,4'-bipyridine in the presence of trimethylsilyl chloride :
The silylated derivative, which is red, is used in salt-free reductions.
4,4′-bipyridine forms a variety of coordination polymers.