Acenaphthene is a polycyclic aromatic hydrocarbon (PAH) consisting of naphthalene with an ethylene bridge connecting positions 1 and 8.
[3] Acenaphthene was prepared for the first time in 1866[4] by Marcellin Berthelot by reacting hot napthalene vapours with acetylene, and a year later he reproduced a similar reaction with ethylene as well as discovered acenaphthene in coal tar.
[5] Later Berthelot and Bardy synthesized the compound by cyclization of α-ethylnaphthalene.
Industrially, it is still obtained from coal tar together with its derivative acenaphthylene (and many other compounds).
Like other arenes, acenaphthene forms complexes with low valent metal centers.