dipolar compounds

Electrically neutral molecules carrying a positive and a negative charge in one of their major canonical descriptions. In most dipolar compounds the charges are delocalized; however the term is also applied to species where this is not the case. 1,2-Dipolar compounds have the opposite charges on adjacent atoms. The term 1,3-dipolar compounds is used for those in which a significant canonical resonance form can be represented by a separation of charge over three atoms (in connection with 1,3-dipolar cycloadditions). Subclasses of 1,3-dipolar compounds include:
  1. Allyl type X=Y+–Z↔︎ X–Y+=Z↔︎ X+–Y–Z↔︎ X=Y–Z+ (X, Z = C, N, or O; Y = N or O)
    See: azo imides, azomethine imides, azomethine ylides, azoxy compounds, carbonyl imides, carbonyl oxides, carbonyl ylides, nitro compounds, nitrones
  2. Propargyl type X≡N+–Z\(\leftrightarrow\) X=N+=Z\(\leftrightarrow\) X=N–Z+\(\leftrightarrow\) X–N=Z (X = C or O, Z = C, N, or O)
    See: azides, diazo compounds, nitrile imides, nitrile oxides, nitrile ylides, nitrilium betaines
  3. Carbene type X:–C=Z\(\leftrightarrow\) X+=C–Z (X = C or N; Z = C, N, or O)
    See: acyl carbenes, betaines, imidoyl carbenes, vinyl carbenes
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1333 (https://doi.org/10.1351/pac199567081307)