24bipyridyl

2,2'-bipyridyl, often abbreviated as bipy or bpy, is a heterocyclic organic compound with the chemical formula (C5H4N)2. It consists of two pyridine rings joined by a single bond at the 2-positions. This molecule is planar and has a delocalized pi electron system. It is a colorless solid that is soluble in many organic solvents.

The most significant property of 2,2'-bipyridyl is its ability to act as a chelating ligand in coordination chemistry. The two nitrogen atoms are positioned to readily bind to metal ions, forming stable five-membered chelate rings. This chelating ability makes it a widely used ligand for a variety of transition metals, including ruthenium, iron, copper, and nickel. The resulting metal complexes often exhibit interesting photophysical and electrochemical properties, leading to applications in areas such as catalysis, dye-sensitized solar cells, and luminescent materials.

Beyond its coordination chemistry, 2,2'-bipyridyl itself can be involved in various organic reactions. Its aromatic rings can undergo electrophilic substitution, although the nitrogen atoms deactivate them somewhat. Derivatives of 2,2'-bipyridyl, where substituents are added to the pyridine rings, are also common and are synthesized to fine-tune the electronic and steric properties of the ligand, thereby influencing the behavior of its metal complexes. For example, introducing electron-donating or withdrawing groups can alter the redox potentials and spectroscopic properties of the corresponding metal complexes.