Sumanene is a polycyclic aromatic hydrocarbon

Polycyclic aromatic hydrocarbon

Polycyclic aromatic hydrocarbons , also known as poly-aromatic hydrocarbons or polynuclear aromatic hydrocarbons, are potent atmospheric pollutants that consist of fused aromatic rings and do not contain heteroatoms or carry substituents. Naphthalene is the simplest example of a PAH...

 and of scientific interest because the molecule

Molecule

A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

 can be considered a fragment of buckminsterfullerene

Buckminsterfullerene

Buckminsterfullerene is a spherical fullerene molecule with the formula . It was first intentionally prepared in 1985 by Harold Kroto, James Heath, Sean O'Brien, Robert Curl and Richard Smalley at Rice University...

. Suman means "sunflower

Sunflower

Sunflower is an annual plant native to the Americas. It possesses a large inflorescence . The sunflower got its name from its huge, fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads...

" in both Hindi

Hindi

Standard Hindi, or more precisely Modern Standard Hindi, also known as Manak Hindi , High Hindi, Nagari Hindi, and Literary Hindi, is a standardized and sanskritized register of the Hindustani language derived from the Khariboli dialect of Delhi...

 and Sanskrit

Sanskrit

Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

. The core of the arene

Arene

Arene or Arênê or Arène may refer to:*an aromatic hydrocarbon*Arene , a genus of marine snails in the family Areneidae*Arene , the wife of Aphareus and mother of Idas and Lynceus in Greek mythology...

 is a benzene

Benzene

Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 ring and the periphery consists of alternating benzene rings (3) and cyclopentadiene

Cyclopentadiene

Cyclopentadiene is an organic compound with the formula C5H6. This colorless liquid has a strong and unpleasant odor. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a Diels–Alder reaction...

 rings (3). Unlike fullerene

Fullerene

A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called carbon nanotubes or buckytubes...

, sumanene has benzyl

Benzyl

In organic chemistry, benzyl is the term used to describe the substituent or molecular fragment possessing the structure C6H5CH2-. Benzyl features a benzene ring attached to a CH2 group.-Nomenclature:...

 positions which are available for organic reaction

Organic reaction

Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical reactions and redox reactions. In organic synthesis,...

s.

Organic synthesis

The structure of Sumanene can be inferred from oxidation of 1,5,9-trimethyltriphenylene

Triphenylene

In chemistry, the organic compound triphenylene is a flat polycyclic aromatic hydrocarbon consisting of four fused benzene rings. Triphenylene can be isolated from coal tar, but it is also made synthetically using benzyn chemistry. One molecule of triphenylene has delocalized 18-π-electron systems...

 but the first practical synthesis starts from norbornadiene

Norbornadiene

Norbornadiene is an organic compound. This bicyclic hydrocarbon is the most stable diolefin derived from the norbornane and norbornene. Norbornadiene is primarily of interest as a ligand in homogeneous catalysis, but it has been heavily studied due to its high reactivity and distinctive...

. Norbornadiene is converted into a stannane

Stannane

Stannane is the hydride of tin. Stannane can be prepared by the reaction of SnCl4 and LiAlH4. Stannane decomposes slowly at room temperature to give metallic tin and hydrogen and ignites on contact with air....

 by action of n-butyllithium

N-Butyllithium

n-Butyllithium is an organolithium reagent. It is widely used as a polymerization initiator in the production of elastomers such as polybutadiene or styrene-butadiene-styrene...

, dibromoethane

Dibromoethane

Dibromoethane can refer to either of two isomeric organobromides with the molecuar formula C2H4Br2:* 1,1-Dibromoethane * 1,2-Dibromoethane See also dibromoethene....

 and tributyltinchloride. A Ullmann reaction

Ullmann reaction

The Ullmann reaction or Ullmann coupling is a coupling reaction between aryl halides with copper. The reaction is named after Fritz Ullmann....

 of this stannane with CuTC

Copper(I)-thiophene-2-carboxylate

Copper-thiophene-2-carboxylate or CuTC is a thiophene and a reagent in organic chemistry that especially promotes the Ullmann reaction between aryl halides....

 affords the benzene core. The 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 ....

 groups created in this conversion then migrate in a tandem ring-opening metathesis and ring-closing metathesis

Ring-closing metathesis

Ring-closing metathesis or RCM is a variation on olefin metathesis that allows the closing of previously hard to make rings...

 by the Grubbs' catalyst

Grubbs' catalyst

Grubbs' Catalyst is a transition metal carbene complex named after Robert H. Grubbs, the chemist who first synthesized it. There are two generations of the catalyst, as shown on the right. In contrast to other olefin metathesis catalysts, Grubbs' Catalysts tolerate other functional groups in the...

. The final structure is obtained by oxidation by DDQ

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone is the chemical reagent with formula C8Cl2N2O2. This oxidant is useful for the dehydrogenation of alcohols, phenols and steroid ketones in organic chemistry. DDQ decomposes in water, but is stable in aqueous mineral acid.-Preparation:Synthesis of DDQ...

.

Properties

Sumanene is a bowl

Bowl (vessel)

A bowl is a common open-top container used in many cultures to serve food, and is also used for drinking and storing other items. They are typically small and shallow, although some, such as punch bowls and salad bowls, are larger and often intended to serve many people.Bowls have existed for...

-shaped molecule

Molecule

A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

 with a bowl depth of 118 picometers. The 6 hub carbon atoms are pyramidalized

Trigonal pyramid (chemistry)

In chemistry, a trigonal pyramid is a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base. When all three atoms at the corners are identical, the molecule belongs to point group C3v. One example of a molecule with a trigonal pyramidal geometry is ammonia...

 by 9° and the molecule displays considerable bond alternation (138.1 to 143.1 pm). Sumanene also experiences bowl-to-bowl inversion with an inversion barrier

Inversion barrier

In molecular geometry, the term inversion barrier refers to the amount of energy required for the geometric structure of a molecule to undergo the conformational change of inversion; i.e. for the molecule to be turned inside out. Nitrogen inversion is one example of such a transition in the...

 of 19.6 kcal/mol

Mole (unit)

The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as an amount of a substance that contains as many elementary entities as there are atoms in 12 grams of pure carbon-12 , the isotope of carbon with atomic weight 12. This corresponds to a value...

 (82 kJ/mol) at 140 °C which is much higher than that found for its corannulene

Corannulene

Corannulene is a polycyclic aromatic hydrocarbon with chemical formula C20H10. The molecule consists of a cyclopentane ring fused with 5 benzene rings, so another name for it is [5]circulene. It is of scientific interest because it is a geodesic polyarene and can be considered a fragment of...

 cousin.
Like any benzylic proton

Hydrogen atom

A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively-charged proton and a single negatively-charged electron bound to the nucleus by the Coulomb force...

, the sumanene protons can be abstracted by a strong base

Base (chemistry)

For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

 such as t-butyl lithium

Organolithium reagent

An organolithium reagent is an organometallic compound with a direct bond between a carbon and a lithium atom. As the electropositive nature of lithium puts most of the charge density of the bond on the carbon atom, effectively creating a carbanion, organolithium compounds are extremely powerful...

 to form the sumanene mono carbanion

Carbanion

A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons. The carbanion exists in a trigonal pyramidal geometry. Formally a carbanion is the conjugate base of a carbon acid.where B...

. This strong nucleophile

Nucleophile

A nucleophile is a species that donates an electron-pair to an electrophile to form a chemical bond in a reaction. All molecules or ions with a free pair of electrons can act as nucleophiles. Because nucleophiles donate electrons, they are by definition Lewis bases.Nucleophilic describes the...

 can react with an electrophile

Electrophile

In general electrophiles are positively charged species that are attracted to an electron rich centre. In chemistry, an electrophile is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile...

 such as trimethylsilyl chloride

Trimethylsilyl chloride

Trimethylsilyl chloride, also known as chlorotrimethylsilane is a silyl halide, with a variety of different uses in chemistry. It has the formula 3SiCl, and under standard conditions it is a colourless liquid, which is stable in the absence of water...

 to the trimethylsilyl

Trimethylsilyl

A trimethylsilyl group is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom [−Si3], which is in turn bonded to the rest of a molecule...

 derivative.

The trianion has also been reported . Electron transport properties have been investigated as well as carbon NMR 

Derivatives

Sumanene derivatives such as naphtosumanene and trisialsumanene have been described. Chiral sumanenes are of some interest with respect to inherent chirality

Inherent chirality

In chemistry, inherent chirality refers to molecules and complexes whose lack of symmetry does not originate from a classic stereogenic element, but is rather the consequence of the presence of a curvature in a structure that would be devoid of symmetry axes in any bidimensional representation.The...

, examples are chiral trimethylsumanene and a chiral sumanene cyclopentadienyl iron complex