Search results for "resorcinarene"
showing 10 items of 166 documents
Recognition of N-Alkyl- and N-Aryl-Acetamides by N-Alkyl Ammonium Resorcinarene Chlorides
2014
N-alkyl ammonium resorcinarene chlorides are stabilized by an intricate array of intra- and intermolecular hydrogen bonds that leads to cavitand-like structures. Depending on the upper-rim substituents, self-inclusion was observed in solution and in the solid state. The self-inclusion can be disrupted at higher temperatures, whereas in the presence of small guests the self-included dimers spontaneously reorganize to 1:1 host-guest complexes. These host compounds show an interesting ability to bind a series of N-alkyl acetamide guests through intermolecular hydrogen bonds involving the carbonyl oxygen (C=O) atoms and the amide (NH) groups of the guests, the chloride anions (Cl(-)) and ammoni…
Synthesis and Characterization of theO-Alkylation Products of Resorcinarene
2013
O-Substitution reactions of tetramethoxyresorcinarene with alkyl halides produced a variety of partially O-alkylated resorcinarene derivatives with terminal alkyne functionality. The degree of alkylation was affected by the reactivity of the alkylating halide used. NMR spectroscopy proved to be an ideal tool for analyzing the complex reaction mixtures and the isolated products based on the symmetry and degree of alkylation of the resorcinarene derivatives. Single-crystal X-ray diffraction studies furthermore showed diversity in the self-assembly of the various O-alkylation products that was greatly affected by the degree of alkylation, as well as the nature of the alkyne moiety.
Cooperative Binding of Divalent Diamides by N-Alkyl Ammonium Resorcinarene Chlorides
2015
N-Alkyl ammonium resorcinarene chlorides, stabilized by an intricate array of hydrogen bonds leading to a cavitand-like structure, bind amides. The molecular recognition occurs through intermolecular hydrogen bonds between the carbonyl oxygen and the amide hydrogen of the guests and the cation-anion circular hydrogen-bonded seam of the hosts, as well as through CH⋅⋅⋅π interactions. The N-alkyl ammonium resorcinarene chlorides cooperatively bind a series of di-acetamides of varying spacer lengths ranging from three to seven carbons. Titration data fit either a 1:1 or 2:1 binding isotherm depending on the spacer lengths. Considering all the guests possess similar binding motifs, the first bin…
Resorcinarene Crowns ☆
2017
Resorcinarene crowns are a class of supramolecular hosts combining a crown ether moiety to a resorcinarene platform as either a podand arm, lower rim substituent, or a bridge. Resorcinarene crowns act as cation hosts and have therefore shown potential in ion transportation and in antibacterial applications.
N-Alkyl ammonium resorcinarene polyiodides
2016
Four N-alkyl ammonium resorcinarene halides incorporating polyiodides were obtained and structurally analyzed by single crystal X-ray crystallography. The unexpected formation of triiodides and pentaiodide anions in these structures was assumed to be the result of the heterolytic dissociation of molecular iodine (I2) in the presence of electron donors in the N-alkyl ammonium resorcinarene halide system, from which I− further binds one or two I2 molecules resulting in I3− or I5− species, respectively.
Recognition of Viologen Derivatives in Water by N-Alkyl Ammonium Resorcinarene Chlorides
2017
Three water-soluble N-alkyl ammonium resorcinarene chlorides decorated with terminal hydroxyl groups at the lower rims were synthesized and characterized. The receptors were decorated at the upper rim with either terminal hydroxyl, rigid cyclohexyl, or flexible benzyl groups. The binding affinities of these receptors toward three viologen derivatives, two of which possess an acetylmethyl group attached to one of the pyridine nitrogens, in water were investigated via 1H NMR spectroscopy, fluorescence spectroscopy, and isothermal titration calorimetry (ITC). ITC quantification of the binding process gave association constants of up to 103 M–1. Analyses reveal a spontaneous binding process whi…
Partial aminomethylation of resorcarenes.
2002
Aminomethylation of resorcarenes at the wider rim with bulky diisopropylamine and formaline leads to trisubstituted derivatives. Analogous reaction with C(2v)-symmetrical resorcarene tetratosylate gives the monoaminomethylated compound. Further reactions of remaining unsubstituted resorcinol rings result in new resorcarene derivatives. [reaction: see text]
Crystal Engineering Studies of the Complexes of Ethyl Resorcinarene with Aromatic Nitrogen Heterocycles
2003
Five X-ray structures of complexes of ethyl resorcinarene with aromatic nitrogen heterocycles (imidazole, 1,2,4-triazole, pyridine, pyrazine, 2-pyridylmethanol and quinoline) show that ethyl resorcinarene spontaneously forms molecular inclusion complexes with five- and six-membered aromatic nitrogen heterocycles via π π and CH π interactions. However, with 10-membered quinoline, no molecular inclusion complex is formed. Instead, quinoline manifests crystal lattice inclusion.
Host-Guest Complexes of C-Ethyl-2-methylresorcinarene and Aromatic
2017
Abstract 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 …
Inverted molecular cups: 1-D and 2-D Ag(I) coordination polymers from resorcinarene bis-thiacrowns
2016
Resorcinarene bis-thiacrown hosts 1–3 were prepared and crystallized with silver trifluoroacetate yielding one and two dimensional Ag coordination polymers. The complexation of silver in exo-cavity fashion folds the thiacrown bridges inwards transforming the resorcinarene hosts into inverted molecular cups. The silver cations were coordinated to the resorcinarene ligands and trifluoroacetate anions, which act as monodentate or bidendate bridging ligands between the metal ions. Argentophilic Ag···Ag (2.93–3.38 Å) interactions supported by two bridging carboxylate anions were found in two of the structures, whereas longer Ag···Ag distances were observed if only one anion connected the silver …