Pillars of assembled pyridyl bis-urea macrocycles: a robust synthon to organize diiodotetrafluorobenzenes

Abstract

Columnar assembled pyridyl bis-urea macrocycles 1 provide a strong 1D supramolecular synthon to construct hierarchical assemblies. These 1D pillars contain ditopic symmetrical acceptors in the form of basic oxygen lone pairs. Herein, we probe this synthon with a series of activated halogen bond donors, the regio-isomers of diiodotetrafluorobenzenes, which vary the relative orientation of the halogen bond formers. Irrespective of the initial stoichiometry, each donor only formed one type of co-crystal with 1. In each case, similar strong pillars of assembled 1 were observed that organize the donors through the CO⋯I interaction, which were significantly shorter than the sum of the van der Waals radii of the atoms involved and among the shortest reported for neutral organic molecules. X-ray photoelectron spectroscopy characteristic core level shifts strongly indicated the formation of halogen bonding interactions.These studies suggest that this synthon can utilize both hydrogen and halogen bonding orthogonally to build complex structures.

Halogen bonding in the co-crystallization of potentially ditopic diiodotetrafluorobenzene: a powerful tool for constructing multicomponent supramolecular assemblies

“…(b) Packing diagrams for (BPyBUM) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\cdot$\end{document} (1,4-DITFB). Reprinted with permission from references [ 86 ] and [ 87 ]. Copyright 2012 and 2017 Royal Society of Chemistry.…”

“…However, the situation is different when pyridyl groups are incorporated into a macrocycle with ureas, such as 1,3-bis((pyridin-2-yl)methyl) bis-urea macrocycle (BPyBUM) [ 87 ]. Two O lone pairs are poised on the exterior per macrocycle, which form both C–I \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\cdots$\end{document} O halogen bonds with the iodine atoms from 1,4-DITFB and N–H \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\cdots$\end{document} O hydrogen bonds with the NH group of ureas, leaving the protected pyridine nitrogen atom free to act as the hydrogen-bonding acceptor of the NH group (Fig.…”

Multidentate, V‐Shaped Pyridine Building Blocks as Tectons for Crystal Engineering

“…By following this strategy, the Shimizu group has synthesised a pyridyl‐bis‐urea macrocycle assembling into a columnar arrangement in the solid state. Despite the lack of pores, the material can take up guests such as trifluoroethanol, I 2 , H 2 or CO 2 [16, 17] . Furthermore, the columnar assemblies have been shown to adsorb and organise small guest molecules that interact via H‐bonds [18] .…”

Temperature-induced pseudopolymorphism of molecular salts from a pyridyl bis-urea macrocycle and naphthalene-1,5-disulfonic acid

“…The assembly leaves the basic oxygen lone pairs on the exterior of the pillars of (1), which participate in noncovalent interactions with acidic alcohols for a wide range of pK a values ranging from 5.5 for tetrafluorophenol to 12.5 for trifluoroethanol (TFE), as well as acting as acceptors for halogen bonds with active donors, such as pentafluoroiodobenzene and diiodotetrafluorobenzenes (Roy et al, 2011(Roy et al, , 2012Som et al, 2017). Thus, assembled molecules of (1) can organize small organic molecules via hydrogen and halogen bonding into interstitial layers between the strong pillars of (1) (Roy et al, 2011;Som et al, 2017). In this article, we report the effects of protonation states of (1) on the subsequent assembly of these salts and/or cocrystals.…”