Tetraphenylmethane is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

consisting of a

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

core with four

phenyl In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula , and is often represented by the symbol Ph (archaically φ) or Ø. The phenyl group is closely related to benzene and can be viewed as a benzene ...

substituent In organic chemistry, a substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. The suffix ''-yl'' is used when naming organic compounds that contain a single bond r ...

s. It was first synthesized by

Moses Gomberg Moses Gomberg (February 8, 1866 – February 12, 1947) was a chemistry professor at the University of Michigan. He was elected to the National Academy of Sciences and the American Philosophical Society, and served as president of the American Chem ...

in 1898.

Synthesis

Gomberg's classical

organic synthesis Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...

shown below starts by reacting triphenylmethyl bromide 1 with

phenylhydrazine Phenylhydrazine is the chemical compound with the formula . It is often abbreviated as . It is also found in edible mushrooms. Properties Phenylhydrazine forms monoclinic prisms that melt to an oil around room temperature which may turn yellow ...

2 to the

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

Oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

with

nitrous acid Nitrous acid (molecular formula ) is a weak and monoprotic acid known only in solution, in the gas phase, and in the form of nitrite () salts. It was discovered by Carl Wilhelm Scheele, who called it " phlogisticated acid of niter". Nitrous ac ...

then produces the

azo compound Azo compounds are organic compounds bearing the functional group diazenyl (, in which R and R′ can be either aryl or alkyl groups). IUPAC defines azo compounds as: "Derivatives of diazene (diimide), , wherein both hydrogens are substituted ...

4 from which on heating above the

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

gas evolves with formation of tetraphenylmethane 5.{{cite journal , title = On tetraphenylmethane , first= M. , last=Gomberg , journal =

J. Am. Chem. Soc. The ''Journal of the American Chemical Society'' (also known as JACS) is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ...

, year = 1898 , volume = 20 , issue = 10 , pages = 773–780 , doi= 10.1021/ja02072a009, url= https://zenodo.org/record/1428930 : Gomberg was able to distinguish this compound from

triphenylmethane Triphenylmethane or triphenyl methane (sometimes also known as Tritan), is the hydrocarbon with the formula (C6H5)3CH. This colorless solid is soluble in nonpolar organic solvents and not in water. Triphenylmethane is the basic skeleton of many syn ...

(

elemental analysis Elemental analysis is a process where a sample of some material (e.g., soil, waste or drinking water, bodily fluids, minerals, chemical compounds) is analyzed for its elemental and sometimes isotopic composition. Elemental analysis can be qualita ...

was not an option given the small differences in the hydrogen fractions of 6.29% and 6.60%) by

nitration In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group () into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters () between Alcohol ...

of 5 with

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

to 6. A strong base would be able to abstract the methine proton of the nitrated triphenylmethyl compound if present, forming a strongly colored compound. He obtained further evidence for the formation of tetraphenylmethane by reducing the nitro groups to

amino In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

groups with

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

dust in

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main compone ...

to the

leuco dye A leuco dye (from the Greek λευκό ''leuko'': white ) is a dye which can switch between two chemical forms, one of which is colorless. Reversible transformations can be caused by heat, light or pH, resulting in examples of thermochromism, ...

7, which on exposure to

hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...

eliminates

aniline Aniline (From , meaning ' indigo shrub', and ''-ine'' indicating a derived substance) is an organic compound with the formula . Consisting of a phenyl group () attached to an amino group (), aniline is the simplest aromatic amine. It is an in ...

to the known compound

pararosaniline Pararosaniline, pararosaniline free base, Basic Red 9, or C.I. 42500 is an organic compound with the formula . It is the free base form of pararosaniline hydrochloride, , a magenta solid with a variety of uses as a dye. It is one of the four comp ...

8. Gomberg's success in synthesizing tetraphenylmethane set him on the attempt to prepare the next homologue

hexaphenylethane Hexaphenylethane is a hypothetical organic compound consisting of an ethane core with six phenyl substituents. All attempts at its synthesis have been unsuccessful. The trityl free radical, Ph3C, was originally thought to dimerize to form hexap ...

, which led him to the discovery of the

triphenylmethyl radical The triphenylmethyl radical (often shortened to trityl radical after 1927 suggestion by Burckhardt Helferich, Helferich et al.) is an organic compound with the formula (C6H5)3C. It is a persistent radical. It was the first radical (chemistry), rad ...

References

Aromatic hydrocarbons Phenyl compounds Substances discovered in the 19th century

Synthesis

See also

References