tsüklopentadienüülrühmaga

Tsüklopentadieen is an organic compound with the chemical formula C5H6. It is a colorless liquid with a distinct, pungent odor. At room temperature, it exists as a highly reactive diene, readily undergoing various chemical reactions. A key characteristic of tsüklopentadieen is its ability to dimerize via a Diels-Alder reaction to form ditsüklopentadieen. This dimerization occurs spontaneously at room temperature but can be reversed by heating, a process known as retro-Diels-Alder.

Tsüklopentadieen is an important building block in organic synthesis. Its aromaticity, or rather its propensity to form an aromatic anion, is significant. The deprotonation of tsüklopentadieen yields the tsüklopentadienyl anion (Cp-), which is a planar, cyclic, and aromatic species with 6 pi electrons, following Hückel's rule. This anion is particularly important in organometallic chemistry, where it acts as a ligand, forming stable complexes with many transition metals. These metal tsüklopentadienyl complexes, often referred to as metallocenes, have found applications in catalysis, particularly in polymerization reactions. The compound is typically synthesized from petroleum-derived feedstocks.