Olympicene is an organic carbon based molecule formed of five rings, of which four are benzene rings, joined in the shape of the

Olympic rings The International Olympic Committee (IOC) uses icons, flags and symbols to elevate the Olympic Games. These symbols include those commonly used during Olympic competition—such as the flame, fanfare and theme—as well as those used throughout ...

. The molecule was conceived in March 2010 as a way to celebrate the

2012 London Olympics The 2012 Summer Olympics (officially the Games of the XXX Olympiad and also known as London 2012) was an international multi-sport event held from 27 July to 12 August 2012 in London, England, United Kingdom. The first event, the ...

by Graham Richards of

University of Oxford , mottoeng = The Lord is my light , established = , endowment = £6.1 billion (including colleges) (2019) , budget = £2.145 billion (2019–20) , chancellor ...

and Antony Williams. It was first synthesized by researchers Anish Mistry and David Fox of the

University of Warwick , mottoeng = Mind moves matter , established = , type = Public research university , endowment = £7.0 million (2021) , budget = £698.2 million (2020 ...

in the UK. Relative energies of olympicene and its isomers were first predicted from quantum electronic-structure computations by Andrew Valentine and David Mazziotti of the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...

Electron counting

Olympicene has 18

pi electrons In chemistry, pi bonds (π bonds) are covalent chemical bonds, in each of which two lobes of an orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally. Each of these atomic orbitals ...

in its ring system; as it is a flat molecule, this makes it an aromatic molecule. The central ring is not an aromatic ring.

Related compounds

A very similar molecule ( benzo 'c''henanthrene) which lacks the -CH₂- spacer between the two sides of the molecule has been known for many years. This earlier molecule has been studied by X-ray crystallography and due to the

steric Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions ...

clash between two hydrogen atoms the molecule is not flat. It is likely that the olympicene is flatter as no steric clash will exist between the two rings. A molecule where the -CH₂- spacer has been replaced with a

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...

(C=O) group (

naphthanthrone Naphthanthrone is an organic carbon based molecule formed of five rings, of which four are benzene rings, joined in the shape of the Olympic rings. The compound can be synthesized by the condensation of pyrene and glycerol in sulfuric acid. Its ...

) has been known for decades. Molecules where the CH₂ spacer has been replaced with oxygen and sulfur atoms have been known for some time. The sulfur compound has a C-S-C angle of 104.53° which suggests that the sulfur atom is an sp³ hybridized atom rather than being sp². This suggests that the sulfur atom is not part of the pi system of the molecule. Olympic Rings

Professor Sir

Martyn Poliakoff Sir Martyn Poliakoff (born 16 December 1947) is a British chemist, working on gaining insights into fundamental chemistry, and on developing environmentally acceptable processes and materials. The core themes of his work are supercritical fluid ...

of the University of Nottingham has pointed out that the Olympic rings are interlinked, rather than tangent as in olympicene, and that a better likeness could be made using

catenane In macromolecular chemistry, a catenane () is a mechanically interlocked molecular architecture consisting of two or more interlocked macrocycles, i.e. a molecule containing two or more intertwined rings. The interlocked rings cannot be se ...

s. A catenane-based olympic molecule was synthesized in 1994 by

Fraser Stoddart Sir James Fraser Stoddart (born 24 May 1942) is a British-American chemist who is Board of Trustees Professor of Chemistry and head of the Stoddart Mechanostereochemistry Group in the Department of Chemistry at Northwestern University in ...

and given the name

olympiadane Olympiadane is a mechanically interlocked molecule composed of five interlocking macrocycles that resembles the Olympic rings. The molecule is a linear pentacatenane or a atenane. It was synthesized and named by Fraser Stoddart and coworkers ...

Synthesis

The synthesis starts using a

Wittig reaction The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent. Wittig reactions are most commonly used to convert aldehydes and ketones to alkenes. Most o ...

pyrene Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is . This yellow solid is the smallest peri-fused PAH (one where the rings are fused through mor ...

carboxaldehyde. To obtain the

ylide An ylide or ylid () is a neutral dipolar molecule containing a formally negatively charged atom (usually a carbanion) directly attached to a heteroatom with a formal positive charge (usually nitrogen, phosphorus or sulfur), and in which both atoms ...

needed, firstly

triphenyl phosphine Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists ...

is reacted with

ethyl bromoacetate Ethyl bromoacetate is the chemical compound with the formula CH2BrCO2C2H5. It is the ethyl ester of bromoacetic acid and is prepared in two steps from acetic acid. It is a lachrymator and has a fruity, pungent odor. It is also a highly toxic alky ...

to form a

phosphonium In polyatomic cations with the chemical formula (where R is a hydrogen or an alkyl, aryl, or halide group). These cations have tetrahedral structures. The salts are generally colorless or take the color of the anions. Types of phosphonium ...

salt; after treatment of this salt with a mild base, the ylide can be reacted with the aldehyde in

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) at ...

. After

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a Catalysis, catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or S ...

of the alpha,beta unsaturated carbonyl compound using

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

and

palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...

in ethyl acetate the ester was converted into the acid chloride using

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

, acid and then

thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately per year bein ...

. By means of a

Friedel–Crafts reaction The Friedel–Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877 to attach substituents to an aromatic ring. Friedel–Crafts reactions are of two main types: alkylation reactions and acylation reactions ...

using

aluminium chloride Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms hexahydrate with the formula , containing six water molecules of hydration. Both are colourless crystals, but samples are often contam ...

dichloromethane Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour is widely used as a solvent. Although it is not miscible with ...

a ketone was formed. On reduction of this ketone using

lithium aluminium hydride Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula Li Al H4. It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic ...

the alcohol 3,4-dihydro-5''H''-benzo 'cd''yren-5-ol was obtained, the 3,4-dihydro-5''H''-benzo 'cd''yren-5-ol was treated with an acid in the form of ion exchange resin to furnish the product.

Images

Preliminary images of it were made using

scanning tunnelling microscopy A scanning tunneling microscope (STM) is a type of microscope used for imaging surfaces at the atomic level. Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer, then at IBM Zürich, the Nobel Prize in Physics in 1986. ...

. More detailed images were made by IBM researchers in Zurich using

non-contact atomic force microscopy Non-contact atomic force microscopy (nc-AFM), also known as dynamic force microscopy (DFM), is a mode of atomic force microscopy, which itself is a type of scanning probe microscopy. In nc-AFM a sharp probe is moved close (order of Angstroms) to ...

in 2012.

References

{{PAHs Polycyclic aromatic hydrocarbons 2012 Summer Olympics Olympic culture

Electron counting

Related compounds

Synthesis

Images

See also

References