Encapsulation of secondary and tertiary ammonium salts by resorcinarenes and pyrogallarenes: the effect of size and charge concentration

Abstract

The binding of different categories of alkyl ammonium (secondary and tertiary mono-and diammonium) salts by resorcinarenes and a pyrogallarene through weak interactions were analysed in all phases. 1 H NMR spectroscopy and electrospray ionisation mass spectrometry were utilized in analysing the complexes in solution and in the gas phase respectively. The 1 H NMR titration studies in methanol-d 4 reveal the association constants for the 1:1 complexes to vary according to the electronic properties of hosts as well as the size, geometric orientation and charge concentration of the guest cations with binding constants of up to 950 M -1 in some cases. Mass spectrometry reveals 1:1 monomeric and 1:2 dimeric complexes in the gas phase. Six co-crystals, three of which are dimeric host-guest capsular assemblies, two open inclusion complexes and a pseudocapsular methanol solvate were analysed in the solid state through single-crystal X-ray diffraction. The crystal structures confirm the complexes to be held together by multiple cation···π, CH···π and hydrogen bond interactions.

Guest-Induced Folding of the N-Benzyl Substituents in an Ammonium Resorcinarene Chloride and the Formation of a Halogen-Bonded Dimer of Capsules

“…20,21 Resorcinarenes in their C 4v conformation are receptors with concave cavities capable of binding small molecules. 22,23 The Nalkyl ammonium resorcinarene salts (NARXs) can act as receptors and/or molecular synthons for the design and construction of larger assemblies. 24−27 They possess a strong circular hydrogen bond (HB) seam (…”

Unprotected Galactosamine as a Dynamic Key for a Cyclochiral Lock

“…Literature suffers from a significant lack of data concerning the amino-sugar discrimination in the gas phase where the solvent interference is suppressed and the noncovalent interactions network prevails, therefore driving the molecular recognition. In the present research, proton-bound complexes of d -galactosamine ( G ) were kinetically investigated in the gas phase through nano-ESI-FT-ICR, the mass spectrometry techniques of choice to gain experimental evidence about the features of gaseous noncovalent architectures. , Resorcin[4]­arenes are herein proposed as alternative cavities − to selectively encapsulate unprotected amino-sugars. The high tunability of resorcin[4]­arenes is due to the possibility of providing it with a chiral domain as a further stereospecific probe to induce guest-fitting.…”

Bamboo-like Chained Cavities and Other Halogen-Bonded Complexes from Tetrahaloethynyl Cavitands with Simple Ditopic Halogen Bond Acceptors

“…Resorcinarenes, [29][30][31][32][33][34][35][36][37] their salts, [38][39][40][41][42][43][44] and resorcinarene cavitands [22][23][24][25][26]28,[45][46][47][48][49] are well-studied families of macrocyclic receptors. Resorcinarenes are particularly useful due to their ease of preparation, simplicity of functionalization, and versatility as hosts for a wide variety of guests.…”

“…Resorcinarenes, − their salts, − and resorcinarene cavitands − ,,− are well-studied families of macrocyclic receptors. Resorcinarenes are particularly useful due to their ease of preparation, simplicity of functionalization, and versatility as hosts for a wide variety of guests. − The known resorcinarene capsules formed through HBs, metal–ligand coordination bonds, and dynamic covalent bonds have recently been reviewed by Kobayashi and Yamanaka .…”

“…Resorcinarenes, − their salts, − and resorcinarene cavitands − ,,− are well-studied families of macrocyclic receptors. Resorcinarenes are particularly useful due to their ease of preparation, simplicity of functionalization, and versatility as hosts for a wide variety of guests. − The known resorcinarene capsules formed through HBs, metal–ligand coordination bonds, and dynamic covalent bonds have recently been reviewed by Kobayashi and Yamanaka . Concurrent with that review, we reported a novel dimeric solid-state capsule held together solely by halogen bonds (XBs) based on a preorganized tetratopic resorcinarene XB acceptor .…”