fenolien

Fenolien, or phenylenes, are a class of hydrocarbon fragments derived from benzene in which two positions on the ring are used to connect to other parts of a molecule. The most common phenylenes are the benzenediyl substituents, designated as o-phenylenyl, m-phenylenyl, and p-phenylenyl, reflecting the ortho, meta, and para relationships of the two attachment points. As building blocks, phenylenes are valued for their rigid, planar aromatic cores that can enforce geometry and promote pi-electron conjugation in larger molecules.

Isomerism among phenylenes affects their properties and how they influence the shape and electronics of the assembled structures. Para-phenylenes tend to support extended, linear conjugation, while ortho- and meta-phenylenes can introduce twists or kinks that alter electronic distribution. Phenylenes can be generated through various synthetic routes, including dehydrogenation or oxidation of suitable dihydrobenzenes, or via cross-coupling methods that install a benzenediyl linkage. They appear as subunits in conjugated polymers and related materials, where they contribute to charge transport, optical properties, and structural rigidity. They also occur in complex polycyclic aromatics and as ligands in coordination chemistry.

In naming, the term phenylene serves as a prefix or suffix in many chemical names, indicating a benzene-derived linking unit. Fenolien/phenylenen units are particularly valued in materials science for their tunable electronics and their role as modular, rigid building blocks in organic synthesis and polymer chemistry.