Bipyridine
Bipyridines also known as bipyridyls, dipyridyls, and dipyridines, are a family of chemical compounds with the formula (C5H4N)2, which are formed by the coupling of two pyridine rings. They are aromatic nitrogen heterocycles that form complexes with most transition metals. They interact with metals via both σ-donating nitrogen atoms and π-accepting molecular orbitals. Bipyridines figure prominently in studies of electron and energy transfer, supramolecular and materials chemistry, and catalysis.