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+–Zmesomer-arrowX–Y+=Zmesomer-arrowX+–Y–Zmesomer-arrowX=Y–Z+ (X, Z = C, N, or O; Y = N or O)
  2. Propargyl type X≡N+–Zmesomer-arrowX=N+=Zmesomer-arrowX=N–Z+mesomer-arrowX–N=Z (X = C or O, Z = C, N, or O)
  3. Carbene type X:–C=Zmesomer-arrowX+=C–Z (X = C or N; Z = C, N, or O)
    PAC, 1995, 67, 1307 (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1333