A staffane or [n]staffane is an organic compound, a polycyclic hydrocarbon with molecular structure H-[-Câ¡(-CH<sub>2</sub>-)<sub>3</sub>â¡C-]<sub>n</sub>-H, for some integer n âÂÂ¥ 1. The chemical formula is therefore C<sub>5n</sub>H<sub>6n+2</sub>
Staffanes were first obtained in 1988 by Piotr Kaszyà Âski and Josef Michl, by spontaneous polymerization of [1.1.1]-propellane C<sub>5</sub>H<sub>6</sub> or C<sub>2</sub>(=CH<sub>2</sub>)<sub>3</sub>. In the reaction, the axial C-C bond of the propellane (the "bridge") is broken, creating a free bond on each of the two axial carbons (the "bridgeheads"). The resulting structural unit [-Câ¡(-CH<sub>2</sub>-)<sub>3</sub>â¡C-] is a rigid cage, consisting of two carbon atoms joined by three methylene bridges; therefore the joined units are constrained to lie on a straight line. This feature has generated substantial interest among nanotechnology researchers, who have considered staffane oligomers as convenient "rigid rods" for building all sorts of nanostructures.
An oligomer with a specific number n of units is named [n]staffane (e.g., [1]staffane is bicyclo[1.1.1]pentane, [2]staffane, etc.) The notation [n]staffane is used when the number of units is variable or unspecified; in this case the "n" in the brackets is not a variable, but the letter "n" iself, and therefore considered part of the name.