pnictogen bond

abbreviation: PnB
https://doi.org/10.1351/goldbook.09033
Weak attractive interaction between an electrophilic region on a pnictogen atom in a molecular entity (wherein the pnictogen is involved in other stronger bonds) and a nucleophilic region in another, or the same, molecular entity.
Notes:
  1. A typical PnB is denoted by the three dots in R−Pn⋅⋅⋅A, wherein R is collectively representing the groups covalently bonded to the pnictogen atom Pn, Pn (the PnB donor atom) is any atom (possibly hypervalent) of Group 15 having at least one electrophilic (electron poor) region (the PnB donor region) involved in a bond with A, R−Pn (the PnB donor) is a molecular entity containing the electrophilic pnictogen atom, and A (the PnB acceptor) is a molecular entity having at least one nucleophilic (electron rich) region (the PnB acceptor region).
  2. An electrophilic region (typically associated with a σ- or π-hole) on a pnictogen atom in a molecular entity and a nucleophilic region in another or the same molecular entity can form bonds spanning a range of separations, energies, and other experimental or theoretical parameters; the use of the term PnB has to be limited to cases where separations, energies, and/or other experimental/theoretical parameters differ from those of corresponding covalent/ionic bonds.
  3. The polar character of the pnictogen atom in the interaction (i.e., the electrophilic role in pnictogen bonded systems or its nucleophilic role in the other systems) is established by considering the physical and chemical properties of the starting molecular entities before the interaction formation and/or of the system assembled by the interaction (see onward).
  4. Bonds wherein a pnictogen atom acts as the nucleophile and those wherein its electrophilic role cannot be identified must not be named PnBs.
  5. Pnictogen atoms can concurrently form one or more than one PnB; the PnB donor and/or PnB acceptor can be charged molecular entities, thus forming charge-assisted PnBs.
Source:
PAC, 2024, 96, 135. (Definition of the pnictogen bond (IUPAC Recommendations 2023)) on page 135 [Terms] [Paper]
Citation: 'pnictogen bond' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.09033 RIS BibTex EndNote
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