Halogen bonding and host-guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests.

Fangfang Pan,John F Trant,Kari Rissanen,Ngong Kodiah Beyeh,Mohadeseh Dashti,Michael R Reynolds

doi:10.3762/bjoc.15.91

Fangfang Pan, John F Trant + Show 4 more

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https://doi.org/10.3762/bjoc.15.91

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Abstract

Single crystal X-ray structures of halogen-bonded assemblies formed between host N-hexylammonium resorcinarene bromide (1) or N-cyclohexylammonium resorcinarene chloride (2), and 1,4-diiodooctafluorobutane and accompanying small solvent guests (methanol, acetonitrile and water) are presented. The guests’ inclusion affects the geometry of the cavity of the receptors 1 and 2, while the divalent halogen bond donor 1,4-diiodooctafluorobutane determines the overall nature of the halogen bond assembly. The crystal lattice of 1 contains two structurally different dimeric assemblies A and B, formally resulting in the mixture of a capsular dimer and a dimeric pseudo-capsule. 1H and 19F NMR analyses supports the existence of these halogen-bonded complexes and enhanced guest inclusion in solution.

Highlights

The construction of specific supramolecular assemblies based on the directional non-covalent bonding has been a central goal of supramolecular chemistry and materials science [1,2,3]
To better understand whether this is fundamental to these systems, or a result of the enforced geometry caused by the included guest, we have extended this study in this current report by excluding the 1,4dioxane molecule as obvious inclusion guests
The deformation shifts the relative positions of the N-alkyl “arms” and the halide anions, which change the relative orientation of DIOFB XB donors when directional halogen bonding forms

Summary

Introduction

The construction of specific supramolecular assemblies based on the directional non-covalent bonding has been a central goal of supramolecular chemistry and materials science [1,2,3]. We have previously shown that N-alkylammonium resorcinarene bromides (NARBrs) can form various halogen-bonded assemblies with the classical organic halogen bond donor 1,4-diiodooctafluorobutane (DIOFB) depending on the solvent, the presence of potential guests, and the length of the alkyl chain [30,31]. The basic conformation of the host N-hexylammonium resorcinarene bromide (Hex-NARBr) was driven by the incorporation of a 1,4-dioxane guest molecule [32], and the inter-cavitand bridging of DIOFB.

Results

Conclusion