Alternative Motifs for Halogen Bonding

Abstract

The halogen‐bonding interaction is one of the rising stars in supramolecular chemistry. Although other weak interactions and their influence on the structure and chemistry of various molecules, complexes and materials have been investigated thoroughly, the field of halogen bonding is still quite unexplored and its impact on chemistry in general is yet to be fully revealed. In principle, every Y–X bond (Y = electron‐withdrawing atom or moiety, X = halogen atom) can act as a halogen‐bond donor when the halogen is polarized enough by Y. Perfluorohalocarbons are iconic halogen‐bond donor molecules in which Y is a perfluorinated aryl or alkyl moiety and X is either iodine or bromine. In this article, alternative halogen‐bond motifs such as X2···A and Ar–X···A [A = Lewis basic halogen‐bond‐accepting atom of a molecule or ion; Ar = neutral or charged (hetero)aromatic system] are reviewed. In addition, haloalkenes, haloalkynes, N‐haloamides and other non‐metallic halogen‐bond donors and their respective halogen‐bonded structures will also be described. Although purely organic halogen‐bonding motifs are very prominent, the role of metal complexes in halogen bonding is becoming increasingly evident as well, which is also reflected in this review. Finally, halogen bonding in solution is briefly highlighted. Contemporary research is proving that halogen bonding is more than a solid‐state phenomenon and is now a well‐recognized weak interaction in chemistry.

Halogen-Bonded Co-Crystals of Aromatic N-oxides: Polydentate Acceptors for Halogen and Hydrogen Bonds

“…This region of positive electrostatic potential, called the "sigma hole" [3,4], is characteristic for halogen atoms attached to an organic backbone, with its magnitude generally decreasing in the order I > Br > Cl > F. Despite similar geometrical features between HB and XB, the halogen bond is still not as well-explored compared to the ubiquitous HB [5][6][7][8][9]. Halogen bonds are frequently studied using nitrogen compounds, which typically display monovalent N···X (X = I, Br) interactions and are well understood as crystal engineering tools for self-assembly processes.…”

Competition between chalcogen bond and halogen bond interactions in YOX4:NH3 (Y = S, Se; X = F, Cl, Br) complexes: An ab initio investigation

“…For a given negative site, the strength of halogen bond interactions usually correlate linearly with the magnitude of the r-hole potential on the halogen atom and more polarizable halogens (Br and I) tend to form stronger halogen bonds than less polarizable ones (F and Cl). Halogen bonds interactions have been studied both theoretically [21][22][23][24][25] and experimentally [26][27][28][29] and their potential applications in various fields of supramolecular chemistry and biochemistry have increasingly been recognized in recent years.…”

Tin···Oxygen Tetrel Bonding: A Combined Structural, Spectroscopic, and Computational Study

“…This field has been the subject of a number of recent reviews, 5,6,7,8 but what comes from experimental and theoretical studies has been the importance of the -hole concept. 9,10,11,12,13,14 Over the past few years other non-conventional noncovalent interactions have gained attention, such as tetrel bonding, 15,16,17,18,19 pnictogen bonding, 20,21,22,23,24,25,26,27,28,29,30,31 chalcogenide bonding, 32,33,34,35,36,37,38,39,40,41,42,43,44 and even aerogen bonding.…”