Amine ($R{\mathrm{NH}}_2,R_2\mathrm{NH},R_3\mathrm{N}$)

A simple neutral amine has nitrogen bonded to one, two, or three groups attached through carbon, with hydrogen filling the remaining positions in the neutral three-bond form. These are the primary, secondary, and tertiary forms respectively. An amide has different connectivity to a carbonyl group. ^[ref]

In neuroscience, a class of transmitters including serotonin and the catecholamines norepinephrine and dopamine. Their effects depend on receptor, pathway and temporal context as well as amount.

A primary alkylamine, ${\mathrm{C}}_6{\mathrm{H}}_{11}\mathrm{N}{\mathrm{H}}_2$, that binds through the nitrogen lone pair as a neutral sigma donor.

An amine with three organic substituents on its nitrogen atom in the ordinary neutral amine classification.

A tertiary amine with three methyl groups. Its nitrogen accepts hydrogen bonds but the molecule has no N–H donor.

An amine with two organic substituents on its nitrogen atom in the ordinary neutral amine classification.

An amine with one organic substituent on its nitrogen atom in the ordinary neutral amine classification.

$\mathrm{C}{\mathrm{H}}_3\mathrm{N}{\mathrm{H}}_2$. reductive amination with an aldehyde can make an N-methyl secondary amine.

A primary amine with both nitrogen lone-pair acceptor ability and N–H donor groups. Self-association differs from that of its constitutional isomer trimethylamine.

Diisopropylethylamine is a sterically hindered tertiary amine base. It can remove protons and trap acid while competing relatively weakly as a nucleophile.

2-Picolylamine is pyridin-2-ylmethanamine, with a pyridine nitrogen and an aminomethyl nitrogen adjacent on the ring. It binds as an unsymmetrical neutral bidentate ligand, forming a five-membered chelate ring.

Dimethylaniline here denotes N,N-dimethylaniline, $\mathrm{PhNM}{\mathrm{e}}_2$. Its neutral amino group donates into the ring, but strong acid protonates nitrogen and changes the directing behavior.

Triethylamine is a tertiary amine, $\mathrm{NE}{\mathrm{t}}_3$, often used to capture acid generated during substitution. Protonation gives triethylammonium.