Sulflower (a

portmanteau A portmanteau word, or portmanteau (, ) is a blend of wordssulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

and

sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...

) is a stable heterocyclic octacirculene based on

thiophene Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. It is a colorless liquid with a benzene-like odor. In most of its reacti ...

. Sulflower does not contain any hydrogen. With molecular formula (C₂S)₈ the compound is considered a type of carbon sulfide. The molecule is flat and together with the 9-membered homolog is at a local strain energy minimum. Its synthesis (a variation of the

Ferrario reaction Ferrario is an Italian surname. Notable people with the surname include: * Bill Ferrario (born 1928), American footballer * Carlo Ferrario (born 1986), Italian footballer * Joseph Anthony Ferrario (1926–2003), American Roman Catholic bishop ...

) is based on

deprotonation Deprotonation (or dehydronation) is the removal (transfer) of a proton (or hydron, or hydrogen cation), (H+) from a Brønsted–Lowry acid in an acid–base reaction.Henry Jakubowski, Biochemistry Online Chapter 2A3, https://employees.csbsju.ed ...

of a tetrathiophene with lithium diisopropylamide followed by reaction with elemental

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

to a sulfur-substituted intermediate followed by

vacuum pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...

. The sulflower molecule has a planar structure with D_8h symmetry, i.e., all eight sulfur atoms as well as the two faces of the molecule are undistinguishable. Because of its planar structure, it is predicted to be able to store many hydrogen molecules between the stacks. The conformation of the H₂ molecule is calculated to be "standing up" over the five membered rings. Detailed DFT calculations have been performed on these molecules.

References

{{Reflist Polycyclic aromatic compounds Thiophenes