Structural Chemistry of Hypervalent Iodine Compounds

Abstract

To quote the modernist architectural mantra: “form follows function.” HVI compounds possess highly unique geometric features, which are highly tunable toward reactivity, making them impressively useful tools in modern synthetic chemistry. This chapter will endeavor to discuss the latest investigations into the structures of λ 3 ‐ and λ 5 ‐iodanes and revisit the past work with fresh insight. A new taxonomy for organizing hypervalent iodine compounds by structure will be introduced. The latest understanding of halogen bonding will be applied to the long‐observed “secondary‐bonding” interactions present in many solid‐state structures. These interactions are now understood to play a key role in the opening stages of reaction mechanisms involving hypervalent iodine reagents, especially in arylation chemistry. The X‐ray crystallographic data from a representative scope of iodanes will be complied in one work, as an easily accessible reference for those new to the field or those cogitating new possible structural motifs to solve synthetic challenges.

Lewis Acidity Scale of Diaryliodonium Ions toward Oxygen, Nitrogen, and Halogen Lewis Bases

“…Structure of Iodonium Base Adducts. Solid-state (Xray) structures 15 of the adducts of the diphenyliodonium ion Ph 2 I + (1a) with chloride, 16 bromide, 16 iodide, 16 different pyridines, 9 18-crown-6, 8 and DABCO 17 have been reported in the literature. The Lewis adducts of 1a with benzoate and pnitrophenolates (4a and 4b), were prepared in this work by anion metathesis reactions (Scheme 2), 18 which were driven by the low solubility of potassium chloride in acetonitrile.…”

A new hypervalent iodine(iii/v) oxidant and its application to the synthesis of 2H-azirines

“…In the past several decades, hypervalent iodine chemistry has witnessed prosperous development in organic synthesis. 1 On one hand, organic chemists are making use of the existing hypervalent iodine oxidants to discover new organic reactions. 2 On the other hand, many endeavors have been devoted to the development of novel hypervalent iodine oxidants, seeking new versatile applications in important synthetic transformations.…”

Remote Substituents as Potential Control Elements for the Solid-State Structures of Hypervalent Iodine(III) Compounds

“…Halogen bonding involving organoiodine compounds has been attributed to the presence of regions of positive electrostatic potential at the iodine center, known as σ holes, that can favorably interact with negatively charged atoms. − A number of reports have examined the theoretical basis for these I···E interactions, and Justik has recently discussed the history and connections between secondary bonding and halogen bonds, in the context of reviewing structural HVI chemistry . Kiprof has shown ab initio molecular orbital calculations focusing on iodine oxygen bonds in hypervalent 10-I-3 iodine compounds …”

“…27 recently discussed the history and connections between secondary bonding and halogen bonds, in the context of reviewing structural HVI chemistry. 33 Kiprof has shown ab initio molecular orbital calculations focusing on iodine oxygen bonds in hypervalent 10-I-3 iodine compounds. 34 The solubility and extended aggregation of HVI compounds can be modulated greatly by introduction of suitable intramolecular substituents to occupy coordination sites about the iodine center that might otherwise be involved in intermolecular interactions.…”