The dibenziodolium cation displays high catalytic activity for the Knorr-type reactions via binding with the carbonyl O atom.

X-ray crystallography data revealed the dichotomy of thiocyanate-involving noncovalent interactions in [Ar¹Ar²I](SCN), as reflected in the generation of two types of supramolecular aggregates: (i) previously unreported 4-membered heterotetramers (Ar¹/Ar² =...

Three diaryliodonium tetrachloroaurates­(III), [Ar1IAr2]­[AuCl4] (Ar1/Ar2 = Ph/Ph (1), Ph/Mes (2), o-(C6H4)2 (3)), were obtained as solids (62–80%) by the metathetical reaction of [Ar1IAr2]­(CF3CO2) and H­[AuCl4]. In particular, the single-crystal X-ray diffraction studies of 1–3 revealed three-center bifurcated C–I···(Cl–Au–Cl) halogen bond (XB) and the more conventional interionic two-center C–I···Cl–Au XB. An XB with the iodine­(III) center of a diaryliodonium cation can be formed even when ∠(C–I···X) is much less than 180° (decrease by 55° in our experiments). A Cambridge Structural Database search and processing revealed other examples of bifurcated XBs involving diaryliodonium species. All recognized bifurcated XBs with diaryliodonium cations were classified and divided into two categories: “bifurcated plus two-center” and “double-bifurcated” structural types. The nature and energies of the XB interactions were studied by density functional theory (DFT) calculations and a topological analysis of the electron density distribution in the framework of the quantum theory of atoms in molecules (QTAIM) at the ωB97XD/DZP-DKH level of theory. The nature of all XB contacts is purely noncovalent, and the total energy of bifurcated XBs is generally ca. 50% higher than the energy of two-center XBs.

Plasmon-assisted transformations of organic compounds represent a novel opportunity for conversion of light to chemical energy at room temperature. However, the mechanistic insights of interaction between plasmon energy and organic molecules is still under debate. Herein, we proposed a comprehensive study of the plasmon-assisted reaction mechanism using unsymmetric iodonium salts (ISs) as an organic probe. The experimental and theoretical analysis allow to exclude the possible thermal effect or hot electron transfer. We found that plasmon interaction with unsymmetrical ISs led to the intramolecular excitation of electron followed by the regioselective cleavage of C-I bond with the formation of electron-rich radical species, which cannot be explained by the hot electron excitation or thermal effects. The high regioselectivity is explained by the direct excitation of electron to LUMO with the formation of dissociative excited state according to quantum-chemical modeling, which provide a novel opportunities to the fine control of reactivity using plasmon energy.

Synthesis and X-ray characterization of the four diaryliodonium tetrachloroplatinates(II) [Ar 1 Ar 2 I] 2 [PtCl 4 ] (Ar 1 / Ar 2 = Ph/Ph (1), 4-Cl-C 6 H 4 /2,4,6-(MeO) 3 C 6 H 2 (2), 4-Me-C 6 H 4 / 2,4,6-(MeO) 3 C 6 H 2 (3), Ph/2,4,6-(MeO) 3 C 6 H 2 (4)) allowed the deterimination of several types of unconventional halogen-bond (HaB) patterns. The first example of a metal-involved trifurcated four-center μ 3 -X•••(X′,X′,M) HaB is represented by the metalinvolving I•••Pt HaB (the structure of 4) with iodonium cations acting as HaB donors, which is supported by two weak I•••Cl HaB contacts. The structures of 1−3 display bifurcated three-center μ 2 -I•••(Cl,Cl) HaBs with iodonium cations. DFT calculations were used to estimate the energetic features of the two types of HaB contacts. Molecular electrostatic potential (MEP) surfaces and noncovalent interaction plot index (NCIPlot) computational tools were used to evaluate the σ-holes and characterize the HaBs, respectively, in all structures.