Biologically, Aniline is an Organic Compound in which a Phenyl Group is attached to an Amino Group.

 

Aniline 

C6H5NH2 is the formula for aniline, an organic compound. Aniline is the most basic aromatic amine, consisting of a phenyl group attached to an amino group. It is a commodity chemical with industrial significance as well as a versatile starting material for fine chemical synthesis. Its primary application is in the production of precursors to polyurethane, dyes, and other industrial chemicals. It has the odour of rotten fish, as do most volatile amines. It burns with a smoky flame, which is typical of aromatic compounds. It is poisonous to humans.

Aniline is an organic chemical compound made up of a phenyl group and an amino group. It is primarily used in the manufacture of polyurethane and other chemical products. It has more electrons than benzene. As a result, it participates in electrophilic aromatic substitution reactions more quickly. Similarly, it is prone to oxidation: while freshly purified aniline is nearly colourless, exposure to air causes gradual darkening to yellow or red due to the formation of strongly coloured, oxidised impurities. Diazotization of aniline produces a diazonium salt, which can then undergo various nucleophilic substitution reactions.

The term "Aniline" is derived from the Portuguese anil, which means "the indigo shrub," with the suffix -ine indicating "derived substance." Aniline, like other amines, is both a base (pKaH = 4.6) and a nucleophile, though to a lesser extent than structurally similar aliphatic amines. Because coal tar was an early source of the benzene from which they are derived, aniline dyes are also known as coal tar dyes.

Aryl-N distances - The CN bond length in aniline is 1.41,[8] compared to 1.47 in cyclohexylamine, indicating partial -bonding between N and C. In Anilines, the C(aryl)-NH2 distance is extremely sensitive to substituent effects. In 2,4,6-trinitroaniline, this distance is 1.34, while in 3-methylaniline, it is 1.44.

The amine in Anilines is a slightly pyramidalized molecule, with nitrogen hybridization occurring between sp3 and sp2. The nitrogen is said to have a high p character. Because of the conjugation of the lone pair with the aryl substituent, the amino group in aniline is flatter (i.e., a "shallower pyramid") than that of an aliphatic amine. The observed geometry is the result of a trade-off between two competing factors: 1) Stabilization of the N lone pair in an orbital with significant s character favours pyramidalization (s character orbitals have lower energy), whereas 2) delocalization of the N lone pair into the aryl ring favours planarity (a lone pair in a pure p orbital has the best overlap with benzene ring orbitals).

Substituted Anilines with electron donating groups are more pyramidalized, whereas those with electron withdrawing groups are more planar. The lone pair in the parent aniline is approximately 12% s character, corresponding to sp7.3 hybridization. (By contrast, alkylamines typically have lone pairs in orbitals close to sp3.) 142.5° is the pyramidalization angle between the C-N bond and the bisector of the H-N-H angle. [14] In comparison, the angle in more strongly pyramidal methylamine is 125°, while formamide has an angle of 180°.