Fluorene is a polycyclic aromatic hydrocarbon insoluble in water and soluble in many organic solvents. Fluorenes are one of the most important fluorescent molecules with applications in polymers, electronic devices, sensors, and photochromic materials.
Aromatic hydrocarbons are cyclic, planar compounds that resemble benzene in electronic configuration and chemical behavior. Benzene has the molecular formula C6H6 and is the simplest aromatic hydrocarbon. The carbon atoms in benzene are linked by six equivalent σ bonds and six π bonds.