A nitrenium ion in organic chemistry

Organic chemistry

Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...

 is a reactive intermediate

Reactive intermediate

In chemistry a reactive intermediate is a short-lived, high energy, highly reactive molecule. When generated in a chemical reaction it will quickly convert into a more stable molecule. Only in exceptional cases can these compounds be isolated and stored, e.g. low temperatures, matrix isolation...

 based on nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 with both an electron lone pair

Lone pair

In chemistry, a lone pair is a valence electron pair without bonding or sharing with other atoms. They are found in the outermost electron shell of an atom, so lone pairs are a subset of a molecule's valence electrons...

 and a positive charge and with two substituents (R₂N⁺). Nitrenium ions are isoelectronic to carbenes, and can exist in either a singlet or a triplet state

Triplet state

A spin triplet is a set of three quantum states of a system, each with total spin S = 1 . The system could consist of a single elementary massive spin 1 particle such as a W or Z boson, or be some multiparticle state with total spin angular momentum of one.In physics, spin is the angular momentum...

. The parent nitrenium ion, NH₂⁺, is a ground state triplet species with a gap of 30 kcal/mol to the lowest energy singlet state. Conversely, most arylnitrenium ions are ground state singlets. Certain substituted arylnitrenium ions can be ground state triplets, however. Currently, nitrenium ions see heavy study in the groups of Matt Platz (Ohio State), Michael Novak (Miami), and Daniel Falvey (University of Maryland).

Aryl nitrenium ions are currently investigated because of their involvement in certain DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 damaging processes. These intermediates can have microsecond or longer lifetimes in water. They can also be exploited for useful synthetic processes.

Nitrenium ions are also intermediates in organic reactions; for instance, the Bamberger rearrangement

Bamberger rearrangement

The Bamberger rearrangement is the chemical reaction of N-phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols...

. They can also act as 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...

s in electrophilic aromatic substitution

Electrophilic aromatic substitution

Electrophilic aromatic substitution EAS is an organic reaction in which an atom, usually hydrogen, appended to an aromatic system is replaced by an electrophile...

.

The term imidonium ion with the same meaning, is now obsolete.