Staffane
Encyclopedia
A staffane or [n]staffane is an organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

, a polycyclic
Polycyclic compound
In organic chemistry, a polycyclic compound is a cyclic compound with more than one hydrocarbon loop or ring structures . In general, the term includes all polycyclic aromatic compounds, including the polycyclic aromatic hydrocarbons, the heterocyclic aromatic compounds containing sulfur,...

 hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

 with molecular structure H-[-C≡(-CH2-)3≡C-]n-H, for some integer n ≥ 1. The chemical formula is therefore C5nH6n+2

Staffanes were first obtained in 1988 by P. Kazynski and J. Michl, by spontaneous polymerization of [1.1.1]-propellane
1.1.1-Propellane
[1.1.1]Propellane is an organic compound, the simplest member of the propellane family. It is a hydrocarbon with formula C5H6 or C23. The molecular structure consists of three rings of three carbon atoms each, sharing one C-C bond....

 C5H6 or C2(=CH2)3. 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 carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

s (the "bridgeheads"). The resulting structural unit [-C≡(-CH2-)3≡C-] is a rigid cage, consisting of two carbon atoms joined by three methylene
Methylene
Methylene is a chemical species in which a carbon atom is bonded to two hydrogen atoms. Three different possibilities present themselves:* the -CH2- substituent group: e.g., dichloromethane ....

 ribs; therefore the joined units are constrained to lie on straight line. This feature has generated substantial interest among nanotechnology
Nanotechnology
Nanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometres...

 researchers, who have considered staffane oligomers as convenient "rigid rods" for building all sorts of nanostructures.

An oligomer
Oligomer
In chemistry, an oligomer is a molecule that consists of a few monomer units , in contrast to a polymer that, at least in principle, consists of an unlimited number of monomers. Dimers, trimers, and tetramers are oligomers. Many oils are oligomeric, such as liquid paraffin...

with a specific number n of units is denoted by [n]staffane (e.g., [1]staffane, [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", considered part of the name.
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