Supramolecular-Macrocycle-Based Crystalline Organic Materials

Supramolecular macrocycles are well known as guest receptors in supramolecular chemistry, especially host-guest chemistry. In addition to their wide applications in host-guest chemistry and related areas, macrocycles have also been employed to construct crystalline organic materials (COMs) owing to their particular structures that combine both rigidity and adaptivity. There are two main types of supramolecular-macrocycle-based COMs: those constructed from macrocycles themselves and those prepared from macrocycles with other organic linkers. This review summarizes recent developments in supramolecular-macrocycle-based COMs, which are categorized by various types of macrocycles, including cyclodextrins, calixarenes, resorcinarenes, pyrogalloarenes, cucurbiturils, pillararenes, and others. Effort is made to focus on the structures of supramolecular-macrocycle-based COMs and their structure-function relationships. In addition, the application of supramolecular-macrocycle-based COMs in gas storage or separation, molecular separation, solid-state electrolytes, proton conduction, iodine capture, water or environmental treatment, etc., are also presented. Finally, perspectives and future challenges in the field of supramolecular-macrocycle-based COMs are discussed.

Facile, one-pot, in aqua synthesis of catalytically competent gold nanoparticles using pyrogallol[4]arene as the sole reagent

Rapid and facile synthesis of macrocycle-capped gold nanoparticles employing pyrogallol[4]arenes as a dual-role reducing and stabilizing agent.

Host-Guest Complexes of C-Ethyl-2-methylresorcinarene and Aromatic N,N'-Dioxides

The C‐ethyl‐2‐methylresorcinarene (1) forms 1:1 in‐cavity complexes with aromatic N,N′‐dioxides, only if each of the aromatic rings has an N−O group. The structurally different C‐shaped 2,2′‐bipyridine N,N′‐dioxide (2,2′‐BiPyNO) and the linear rod‐shaped 4,4′‐bipyridine N,N′‐dioxide (4,4′‐BiPyNO) both form 1:1 in‐cavity complexes with the host resorcinarene in C_4v crown and C_2v conformations, respectively. In the solid state, the host–guest interactions between the 1,3‐bis(4‐pyridyl)propane N,N′‐dioxide (BiPyPNO) and the host 1 stabilize the unfavorable anti‐gauche conformation. Contrary to the N,N′‐dioxide guests, the mono‐N‐oxide guest, 4‐phenylpyridine N‐oxide (4PhPyNO), does not form an in‐cavity complex in the solid state. The host–guest complexation and the relative guest affinities were studied through ¹H NMR competition experiments in methanol. Single‐crystal X‐ray crystallography of the 1:1 complexes supports the proposed solution‐state structures, also revealing strong hydrogen bonds between the host and the guests, not observed in solution owing to hydrogen/deuterium (H/D) exchange processes in methanol.

Conversion of Pregabalin to 4-Isobutylpyrrolidone-2

Solid-state studies of C-butyl-resorcin[4]arene with pregabalin (Lyrica, Nervalin) in nitrobenzene yielded a cocrystal of C-butyl-resorcin[4]arene with 4-isobutylpyrrolidone-2. A combined experimental and quantum chemical investigation was implemented to further our understanding of the factors affecting the conversion process.

Aromatic N-oxide templates open inclusion and dimeric capsular assemblies with methylresorcinarene

Multiple weak interactions are manifested in the complexation of pyridine N-oxide and quinoline N-oxide by methylresorcinarene resulting to 1 : 1 assemblies in solution, with 2 : 3 and 2 : 2 host–guest dimeric capsules respectively in the solid state.

Engineering supramolecular organic frameworks (SOFs) of C-alkylpyrogallol[4]arene with bipyridine-based spacers

Supramolecular organic frameworks (SOFs) based on pyrogallol[4]arene and 4,4′-bipyridine-type spacer molecules have been investigated.

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

Multiple weak interactions are manifested in the complexation of different categories of secondary and tertiary alkyl ammonium salts with resorcinarenes and pyrogallarene leading to open inclusion and dimeric capsular assemblies with varying binding affinities, and analyzed in solid, liquid and gas phases.

Establishing trends based on solvent system changes in cocrystals containing pyrogallol[4]arenes and fluorescent probes rhodamine B and pyronin Y

Eight cocrystal structures containing a pyrogallol[4]arene of varying aliphatic tail lengths and either fluorescent probes rhodamine B or pyronin Y in a range of solvent systems are examined. Trends based on probe, solvent, and aliphatic tail length are investigated.

Solvent control in the formation of supramolecular host–guest complexes of isoniazid with p-sulfonatocalix[4]arene

The position of the anti-tuberculosis drug isoniazid inside (endo) or outside (exo) to the macrocyclic cavity of p-sulfonatocalix[4]arene can be regulated by the appropriate choice of the solvent system.

Cocrystallization of pyrogallol[4]arenes with 1-(2-pyridylazo)-2-naphthol

Mapping the effects of various solvent systems and varying aliphatic tails lengths of cocrystals composed of pyrogallol[4]arenes and 1-(2-pyridylazo)-2-naphthol.

Illuminating host–guest cocrystallization between pyrogallol[4]arenes and the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate

Symmetry-generated packing of a cocrystal composed of c-butyl-pyrogallol[4]arene and the ionic liquid, 1-ethyl-3-methylimidazolium ethylsulfate.