4,4'-Bipyridine

4,4′-Bipyridine (abbreviated to 4,4′-bipy or 4,4′-bpy) is an organic compound with the formula (C₅H₄N)₂. 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 [(C₅H₄NCH₃)₂]²⁺, known as paraquat.

4,4′-Bipyridine

Names
Preferred IUPAC name 4,4′-Bipyridine
Identifiers
CAS Number	553-26-4 Y
3D model (JSmol)	Interactive image
Beilstein Reference	113176
ChEBI	CHEBI:30985 Y
ChEMBL	ChEMBL1374568
ChemSpider	10636 Y
ECHA InfoCard	100.008.216
EC Number	209-036-3
Gmelin Reference	3759
PubChem CID	11107
UNII	X4O2OD61CB
CompTox Dashboard (EPA)	DTXSID2027200
InChI InChI=1S/C10H8N2/c1-5-11-6-2-9(1)10-3-7-12-8-4-10/h1-8H N Key: MWVTWFVJZLCBMC-UHFFFAOYSA-N N
SMILES c1cnccc1-c2ccncc2
Properties
Chemical formula	C10H8N2
Molar mass	156.188 g·mol−1
Melting point	114 °C (237 °F; 387 K)
Boiling point	305 °C (581 °F; 578 K)
Structure
Dipole moment	0 D
Related compounds
Related compounds	2,2′-Bipyridine Pyridine 4-Pyridylnicotinamide Terpyridine Biphenyl
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

History

4,4′-Bipyridine was first obtained in 1868 by the Scottish chemist Thomas Anderson via heating pyridine with sodium metal.^[1] However, Anderson's empirical formula for 4,4′-bipyridine was incorrect.^[2] 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.^[3]

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.^[4]

Reactions

The reducing agent is N,N'-bis(trimethylsilyl)-4,4'-bipyridinylidene is produced by reduction of 4,4'-bipyridine in the presence of trimethylsilyl chloride (Me = CH₃):

NC₅H₄C₅H₄N + 2 Li + 2 Me₃SiCl → Me₃SiNC₅H₄C₅H₄NSiMe₃ + 2 LiCl

The silylated derivative, which is red, is used in salt-free reductions.^[5]

4,4′-bipyridine forms a variety of coordination polymers.^[6]

References

1. See:

   • Anderson, Thomas (1868). "On the products of the destructive distillation of animal substances. Part V." Transactions of the Royal Society of Edinburgh. 25: 205–216. doi:10.1017/S0080456800028167. S2CID 251577345. Anderson called 4,4′-bipyridine "Dipyridine".
   • German translation: Anderson, Th. (1870). "Ueber die Producte der trockenen Destillation thierischer Materien. Fünfter Theil" [On the products of the dry distillation of animal materials. Fifth part.]. Annalen der Chemie und Pharmacie (in German). 154: 270–286. doi:10.1002/jlac.18701540303.
   • See also: Fehling, Hermann Christian von, ed. (1890). Neues Handwörterbuch der Chemie [New Concise Dictionary of Chemistry] (in German). Vol. 5. Braunschweig, Germany: Friedrich Vieweg und Sohn. p. 974. See γ-Dipyridyl.
2. Anderson gave the empirical formula for 4,4′-bipyridine as C₁₀H₁₀N₂. See:

   • (Anderson, 1868), p. 209.
   • (Fehling, 1890), p. 974 (γ-Dipyridyl).
3. Weidel, H.; Russo, M. (1882). "Studien über das Pyridin" [Studies of pyridine]. Monatshefte für Chemie (in German). 3: 850–885. doi:10.1007/BF01516855. S2CID 97065714. The empirical formula for 4,4′-bipyridine (γ-Dipyridyl) appears on p. 856 ; the molecular structure of 4,4′-bipyridine (γ-Dipyridyl) appears on p. 867.
4. "Paraquat and Diquat". IPCS INCHEM.
5. Tsurugi, Hayato; Mashima, Kazushi (2019). "Salt-Free Reduction of Transition Metal Complexes by Bis(trimethylsilyl)cyclohexadiene, -dihydropyrazine, and -4,4′-bipyridinylidene Derivatives". Accounts of Chemical Research. 52 (3): 769–779. doi:10.1021/acs.accounts.8b00638. PMID 30794373. S2CID 73505603.
6. Biradha, K.; Sarkar, M.; Rajput, L. (2006). "Crystal engineering of coordination polymers using 4,4′-bipyridine as a bond between transition metal atoms". Chemical Communications (40): 4169–79. doi:10.1039/B606184B. PMID 17031423.