From Self-sufficiency
Jump to: navigation, search
style="background: #F8EABA; text-align: center;" colspan="2" | Identifiers
CAS number 366-18-7
ChemSpider 13867714
RTECS number DW1750000
SMILES Script error: No such module "collapsible list".
style="background: #F8EABA; text-align: center;" colspan="2" | Properties
Molecular formula C10H8N2
Molar mass 156.18 g mol−1
Melting point

70-73 °C

Boiling point

273 °C

style="background: #F8EABA; text-align: center;" colspan="2" | Structure
Dipole moment 0 D
style="background: #F8EABA; text-align: center;" colspan="2" | Hazards
R-phrases 25
S-phrases 36/37-45
style="background: #F8EABA; text-align: center;" colspan="2" | Related compounds
Related compounds 4,4'-Bipyridine
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

2,2'-Bipyridine is a organic compound with the formula (C10H8N2). This colorless solid, commonly abbreviated bipy or bpy (pronounced "b-pee"), is an important isomer of the bipyridine family. It is a bidentate chelating ligand, forming complexes with many transition metals. Ruthenium complex and platinum complexes of bipy exhibit intense luminescence, which may have practical applications.

Preparation and general properties

It is prepared by the dehydrogenation of pyridine using Raney nickel:[1]


Although uncoordinated bipyridine is often drawn with its nitrogen atoms in cis conformation, the lowest energy conformation both in solid state and in solution is in fact coplanar, with nitrogen atoms in trans position. Only in acidic solution bipyridine adopts a cis conformation.[2] The related N-heterocyclic ligand phenanthroline does not have the same conformational flexibility and tends to bind metal ions more strongly.

Reflecting the popularity of this ligand design, many substituted variants of bipy have been described.[3][4]

Coordination chemistry

Illustrative complexes

Tris-bipy complexes

Bipyridine complexes absorb intensely in the visible part of the spectrum. The electronic transitions are attributed to metal-to-ligand charge transfer (MLCT). In the "tris(bipy) complexes" three bipyridine molecules coordinate to a metal ion, written as [M(bipy)3]n+ (M = metal ion; Cr, Fe, Co, Ru, Rh and so on; bipy = 2,2'-bipyridine). These complexes have six-coordinated, octahedral structures and two enantiomers as follows:

Three dimensional view of the [Fe(bipy)3]2+ complex.

These and other homoleptic tris-2,2'-bipy complexes of many transition metals are electroactive. Often, both the metal centred and ligand centred electrochemical reactions are reversible one-electron reactions that can be observed by cyclic voltammetry. Under strongly reducing conditions, most tris(bipy) complexes can be reduced to neutral derivatives containing bipy- ligands. Examples include M(bipy)3, where M = Al, Cr, Si.


  1. Sasse, W. H. F. (1973), "2,2'-Bipyridine", Org. Synth. ; Coll. Vol., 5: 102  Missing or empty |title= (help)
  2. Göller, A.; Grummt, U.-W.; "Torsional barriers in biphenyl, 2,2'-bipyridine and 2-phenylpyridine", Chem. Phys. Lett. 2000, 321, 399-405.
  3. Smith, A. P.; Lamba, J. J. S.; Fraser, C. L. (2004), "Efficient Synthesis of Halomethyl-2,2'-Bipyridines: 4,4'-Bis(chloromethyl)-2,2'-Bipyridine", Org. Synth. ; Coll. Vol., 10: 107  Missing or empty |title= (help)
  4. Smith, A. P.; Savage, S. A.; Love, J.; Fraser, C. L. (2004), "Synthesis of 4-, 5-, and 6-Methyl-2,2'-Bipyridine by a Negishi Cross-Coupling Strategy", Org. Synth. ; Coll. Vol., 10: 517  Missing or empty |title= (help)
  5. Lay, P. A.; Sargeson, A. M.; Taube, H. (1986). "cis-Bis(2,2'-Bipyridine-N,N') Complexes of Ruthenium(III)/(II) and Osmium(III)/(II)". Inorg. Synth. 24: 291–299. doi:10.1002/9780470132555.ch78. 

it:2,2'-bipiridina nl:2,2'-bipyridine pt:2,2'-bipiridina fi:2,2'-Bipyridiini zh:2,2'-联吡啶