fenyyliryhmästä

Fenyyliryhmä, often referred to as a phenyl group, is a cyclic organic substituent derived from benzene. Its chemical formula is C₆H₅−. In this structure, five hydrogen atoms of a benzene molecule are replaced by a bond to another atom or group. The phenyl group is a fundamental building block in organic chemistry and is found in a vast number of organic compounds, including pharmaceuticals, dyes, and polymers.

The phenyl group is a planar, aromatic ring. Its aromaticity contributes to its stability and reactivity. When attached to a molecule, the phenyl group can influence the physical and chemical properties of that molecule. For instance, it can increase lipophilicity, which is important in drug design for absorption and distribution within the body. It can also participate in various chemical reactions, such as electrophilic aromatic substitution, due to the electron-rich nature of the benzene ring.

The term "phenyl" is commonly used in naming organic compounds. For example, compounds containing a phenyl group attached to an alkyl chain are called alkylbenzenes, like toluene (methylbenzene). When a phenyl group is bonded to a hydroxyl group, it forms phenol. The presence of one or more phenyl groups in a molecule can significantly alter its electronic and steric properties, making it a versatile functional group in synthetic chemistry and a key component in many naturally occurring and synthetic substances.