9-Methylene-fluorene

9-Methylene-fluorene or dibenzofulvene (DBF) is a polycyclic aromatic hydrocarbon with chemical formula (C6H4)2C\dCH2. It is best known as one product from deprotection of the Fmoc group. It can be prepared by treatment of 9-hydroxymethylfluorene with strong base.

Properties
It is an analog of a 1,1-diphenylethylene. Polymerization of 9-methylene-fluorene produces a π-stacked polymer.