Systematic name	2,2'-bipyridine
Chemical formula	C10H8N2
Molecular mass	xx.xx g/mol
Density	x.xxx g/cm3
Melting point	xx.x °C
Boiling point	xx.x °C
CAS number	*
SMILES	xxxx
Chemical infobox

Bipyridine is one of the simplest polypyridine compounds. It consists of two pyridine molecules bound with a single bond, reflected in its molecular formula: C₁₀H₈N₂.

Bipyridine is a white solid, soluble in organic solvents, and slightly soluble in water. There are six isomers of bipyridine; among them, a well-known structure is 2,2'-bipyridine.

2,2'-bipyridine is a chelate ligand and forms a complex with a transition metal ion. The bipyridine-coordinated complexes are typical examples of polypyridine complexes. The bipyridine complexes in which three bipyridine molecules are coordinated to a metal ion are called trisbipyridine complexes, written as ^*n+ (M = metal ion; Cr, Fe, Co, Ru, Rh and so on; bpy = 2,2'-bipyridine). The abbreviation bpy is often pronounced "bippy" by chemists in the lab. The complexes have six-coordinated, octahedral structures and two enantiomers as follows:

The bipyridine complexes exhibit characteristic optical properties. For example, an iron complex, ^*2+, exhibits strong absorption attributed to metal-to-ligand charge transfer (MLCT) in the visible light region, so this complex is used for the colorimetric analysis of iron ions. A ruthenium complex and a platinum complex exhibit luminescence, and these complexes are expected to be used for luminescent materials.

The homoleptic tris-2,2'-bipy complexes of many transition metals are electroactive species. Normally both the metal centred and ligand centred electrochemical reactions are reversible one electron reactions which can be observed by cyclic voltammetry.

4,4'-bipyridine (4,4'-bipy) is a ligand which can bridge between metal centres; using this compound a series of polymers of metal centres connected by the bipy units have been made.

Pyridines | Chelating agents

Bipyridin | ビピリジン