Orbital analysis of bonding in diarylhalonium salts and relevance to periodic trends in structure and reactivity

Abstract

A revised bonding model for diarylhalonium salts, that involves partial s-orbital contribution, provides new insight into periodic trends in structure and reactivity.

Halonium, chalconium, and pnictonium salts as noncovalent organocatalysts: a computational study on relative catalytic activity

“…2). Since it has been shown theoretically and experimentally that cyclic dibenzohalolium cations (7-9) exhibit a higher Lewis acidity and catalytic activity than their acyclic analogues, namely diarylhalonium cations Ar 2 X + , 51,54,71 in this study we focused on the cyclic derivatives 1-9. Cations 1-3 represent pnictonium(V) derivatives, whereas species 4-6 are the representative examples of sulfonium, selenonium, and telluronium cations, respectively.…”

“…[40][41][42][43][44][45][46][47][48][49][50][51] It is worth mentioning that diarylbromonium salts (F; X = Br) have also been reported to exhibit high catalytic activity. [52][53][54][55] Organocatalysts based on ChB donors have gained increasing attention over the last five years. [56][57][58][59][60][61][62][63][64] A series of publications give unambiguous evidence that the catalytic activity of ChB donating species shows a trend similar to that of XB donors, namely the catalytic activity gradually increases from S to Te, and it is higher for cationic species compared to uncharged chalcogen-containing compounds.…”

“…40–51 It is worth mentioning that diarylbromonium salts ( F ; X = Br) have also been reported to exhibit high catalytic activity. 52–55…”

A quantum-chemical analysis on the Lewis acidity of diaryl-halonium ions

“…The relative binding energies are also in line with the recent experimental measurements of Stuart and co-workers, using neutral Lewis bases. [24] As mentioned, SAPT analyses shed some light on the differences between these three cases (see Figure 8). The dispersion term differences are marginal compared to the other terms.…”

“…[13], [14] As bromolium catalysts sometimes outperformed iodolium ones, X the order in Lewis acidity remained unclearuntil very recently, when Stuart and co-workers reported insights on the nature of bonding and behavior of these diarylhalonium ions. [24] Herein, we aim to finally elucidate the origin of the higher Lewis acidity of iodolium vs. diaryliodonium salts via an in-depth analysis of the hybridization of these species and via energy decomposition analyses. The latter tool is also employed to gain additional insights into the effects governing the relative Lewis acidities of the three higher halolium salts.…”