pyridin4yl

Pyridin-4-yl, also written as 4-pyridyl, is a monovalent substituent derived from pyridine by removing a hydrogen atom at the 4-position (para to the nitrogen). It is used as a building block in organic synthesis and as a coordinating fragment in inorganic and materials chemistry. The systematic IUPAC name is pyridin-4-yl.

Structure and properties: The substituent consists of a pyridine ring attached through its carbon at position 4 to another moiety. The ring remains planar and aromatic, and the pyridine nitrogen provides a Lewis base site that can coordinate to metal centers. The 4-pyridyl group is relatively electron-poor compared with phenyl, a factor that influences its coordination behavior and reactivity in cross-coupling and other transformations.

Applications: 4-Pyridyl groups are widely used as ligands and linkers in coordination chemistry, metal-organic frameworks (MOFs), and supramolecular assemblies, thanks to the pyridine nitrogen’s ability to bind metals and to bridge units. In organic synthesis, the 4-pyridyl fragment is commonly installed via cross-coupling methods, such as Suzuki–Miyaura couplings using 4-pyridyl boronic acids or 4-pyridyl halides, as well as other C–H activation or substitution strategies. 4-Pyridyl motifs also appear in pharmaceutical and agrochemical research as heteroaromatic components that can influence binding, metabolism, and pharmacokinetic properties.

See also: pyridine, pyridinyl, 4-substituted arylpyridines.