[N⋅⋅⋅I⁺⋅⋅⋅N] Halogen‐Bonded Dimeric Capsules from Tetrakis(3‐pyridyl)ethylene Cavitands

Abstract

Two [N⋅⋅⋅I ⋅⋅⋅N] halogen-bonded dimeric capsules using tetrakis(3-pyridyl)ethylene cavitands with different lower rim alkyl chains are synthesized and analyzed in solution and the gas phase. These first examples of symmetrical dimeric capsules making use of the iodonium ion (I ) as the main connecting module are characterized by H NMR spectroscopy, diffusion ordered NMR spectroscopy (DOSY), electrospray ionization mass spectrometry (ESI-MS), and ion mobility-mass spectrometry (TW-IMS) experiments. The synthesis and effective halogen-bonded dimerization proceeds through analogous dimeric capsules with [N⋅⋅⋅Ag ⋅⋅⋅N] binding motifs as the intermediates as evidenced by the X-ray structures of (CH Cl ) @[3 a ⋅Ag ⋅(H O) ⋅OTs ] and (CH Cl ) @[3 a ⋅Ag ⋅(H O) ⋅OTs ], two structurally different capsules.

Halogen Bonding Helicates Encompassing Iodonium Cations

“…Thehelicity of 4 and 8 in solution was confirmed by NOE correlations indicating dipolar relaxation between hydrogens of distinct pyridyl groups (Figure 3a nd Supporting Information). Such proximity of the pyridines implies ah elical conformation, considering the symmetry of the complexes indicated by 1 H, 13 C, and 15 NNMR. NOE correlations also show evidence for ahelix conformation of ligand 6,and DFT calculations found the helix to be aplausible conformation of 6 (Supporting Information).…”

“…[8a,b, 11] Halonium ions are strong halogen-bond donors that tend to form symmetric three-center,f ourelectron (3c-4e) bonds,f or example an [N À I À N] + halogen bond between two nitrogen Lewis bases. [12] Such 3c-4e halogen bonds have been previously used to form supramolecular capsules, [13] and for stabilization of halonium ions in synthetic reagents applied to halonium transfer and oxidation reactions. [14] Polymer and oligomer helices have been widely used in organic synthesis.…”

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

“…For example, the X···N distances in bis(pyridine)iodonium(I) tetrafluoroborate constitute an R XB value compounds are classified as halogen bonds of covalent nature [14]. Carefully designed nitrogen compounds are successfully utilized as molecular building blocks engaging in (N−X−N)⁺X − XBs to construct supramolecular structures resembling metal coordination frameworks [15]. However, weaker C−I···N XBs with typical RXB values ranging from 0.75 to 0.90 are still of considerable importance for applications in materials chemistry, e.g., for triggering liquid crystallinity and gelation behaviour [16][17][18].…”

An Intramolecular C(sp2)–H Amidation Using N‐Iodosuccinimide

“…In this work, the formation of an N ··· I + ··· π intermediate might be crucial to bring together the imine double bond and the nitrogen center for the oxidative coupling. [26b], Thus, the reaction was carried out under mild conditions (Figure c). Hence, we anticipated that this C–N coupling reaction of nonprefunctionalized C–H and N–H bonds would be carried out under metal‐free, base‐free, and mild conditions.…”