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Abstract: This Letter reports the evidences for intramolecular six-membered N–H···O hydrogen bonding in N-benzyl benzamides and five-membered N–H···N hydrogen bonding in N-(pyridin-2-ylmethyl) benzamide. Intramolecular six-membered N–H···X (X=O or F) hydrogen bonding in 2-methoxyl- or 2-fluorobenzamides is used to lock the amide proton from forming strong intermolecular N–H···On bonding. As a result, for the first time the new intramolecular hydrogen bonding patterns are observed in the crystal structures of nine amides, whereas the whole molecules give rise to a new class of three-center hydrogen bonding motif. 1H NMR study in chloroform-d also supports that this weak intramolecular hydrogen bonding pattern exists in solution. [Copyright &y& Elsevier]

Abstract: The capacity of sulfur to form intramolecular five- or six-membered S⋯H–N hydrogen bonding in aromatic amides is assessed. The five-membered S⋯H–N hydrogen bonding is observed in crystal structures of five compounds, whereas the six-membered S⋯H–N hydrogen bonding is revealed in crystal structures of three compounds. The trityl group has been used to promote formation of the weak hydrogen bonding because it efficiently inhibits the competition of the intermolecular CH–N hydrogen bonding. (2D) 1H NMR experiments indicate that both patterns also exist in chloroform. [Copyright &y& Elsevier]

Abstract: Intramolecular three-centered hydrogen bonding has been used to induce dipyridyl anthranilamide 5 and diphenylacetylene anthranilamide 11 to adopt rigid straight conformation. Compound 5 reacted with Pd(dppp)(OTf)2 ( 12a ) or Pt(dppp)(OTf)2 ( 12b ) in dichloromethane to afford square metallocyclophanes 13a and 13b in 70% and 40% yield, respectively. In contrast, the reaction of 11 with 12b in dichloromethane gave triangular metallocyclophane 14 in 15% yield. [Copyright &y& Elsevier]

Four hydrogen bonded rigid aromatic hydrazide macrocycles, which bear different number of chiral and/or achiral oligo(ethylene glycol) chains, have been synthesized. 1 H NMR, fluorescence, UV–vis absorption, and circular dichroism experiments showed that the three macrocycles bearing chiral side chains gave rise to one-dimensional chiral column aggregates in aqueous solution. Remarkably, the chiral side chains at two different positions induced the helicity chirality in opposite directions. [ABSTRACT FROM AUTHOR]

Abstract: Two 1,2,3-triazole- and amide-incorporated macrocycles have been prepared by 1,3-dipolar cycloaddition of the corresponding dialkyne and diazide precursors. Intramolecular C–H⋯O hydrogen bonding is introduced to lock the C5–H atoms of the 1,2,3-triazole rings. The binding of the two macrocycles to amide, monosaccharide, and halide derivatives in chloroform or dichloromethane has been investigated. It is revealed that the amide units dominate their binding toward the amide and monosaccharide guests through forming intermolecular hydrogen bonding and 1,2,3-triazole is as weak as an intermolecular hydrogen bonding acceptor, but it forms intermolecular halogen bonding when cooperative effect exists. [Copyright &y& Elsevier]

Abstract: Self-sorting is commonplace in biological system but seldom applied to orthogonally fabricating micro/nanoscaled objects. In this Letter, this principle has been employed to construct two different microscaled architectures via self-sorted assembly of size-matched disk-like molecules. A remarkable cooperative reinforcement of hydrogen-bonding and donor–acceptor interaction is also observed. [Copyright &y& Elsevier]

Abstract: Six-petal microflowers have been self-assembled in methanol from C 3-symmetric shape-persistent triangular aromatic hydrazide derivatives. Nine intramolecular hydrogen bonds are used to enhance the planarity of the aromatic backbone, while six 2-(2-(2-methoxyethoxy)ethoxy)-ethoxyl groups are appended to the rigid aromatic backbone. Scanning electron microscopy (SEM) images show that the molecules form unique six-petal flower-like aggregates in methanol. A self-assembling mechanism that is similar to the formation of snowflakes has been proposed. [Copyright &y& Elsevier]

Abstract: This Letter describes 2-(2-(dioctylamino)-2-oxoethyl-amino)-2-oxoethoxyl (DOAOE)-tuned self-assembly of vesicles from rigid macrocycles and foldamer-like oligomers. The molecules are prepared through the formation of reversible hydrazone bonds from aldehyde and benzo-hydrazide precursors, which are further facilitated by intramolecular N⋯H–O hydrogen bonding. SEM, AFM, and fluorescent encapsulation studies reveal that the molecules all self-assemble into vesicular structures in methanol, while similar molecules bearing the triethylene glycol or n-decyl chains do not. The results illustrate that DOAOE is robust in promoting the formation of vesicles for aromatic systems in polar solvents. [Copyright &y& Elsevier]

Abstract: Two new hydrazide-based quadruple hydrogen-bonding motifs are described. Dipodals based on these two motifs are revealed to form supramolecular polymers, which can further aggregate to form vesicles and/or organogels in hydrocarbons. The quadruple hydrogen-bonding motifs are characterized by the X-ray diffraction and (2D) 1H NMR experiments, while the vesicles and organogels are evidenced by SEM, AFM, TEM, and fluorescent microscopy. [Copyright &y& Elsevier]

Abstract: This Letter reports the synthesis of three dicationic and two hexacationic receptors in which two porphyrin units are connected with an aryl amide linker. 1H NMR and X-ray crystal structure analysis for model compounds show that in aqueous or DMSO medium the receptors could adopt preorganized U-styled conformation due to intramolecular hydrogen bonding-induced rigidity of the amide linker. 1H NMR, UV–vis and fluorescent investigations revealed that the ionic receptors efficiently complex C60C in aqueous medium with cooperative intermolecular electrostatic and donor–acceptor interactions as driving forces. A 1:1 binding stoichiometry has been established for the complexes and the related association constants have been evaluated. [Copyright &y& Elsevier]

Abstract: This Letter reports the design and synthesis of a new type of hydrogen bonding-mediated foldamer-derived tweezer receptors that are incorporated with two peripheral (zinc)porphyrin units. Due to the existence of four intramolecular hydrogen bonds, the (zinc)porphyrin units are forced to approach and stack with each other. 1H NMR and fluorescent studies revealed that the new receptors could form 1:1 complexes with planar electron-deficient molecules such as naphthalene and benzene diimides and paraquat through a unique sandwich-styled binding pattern. The association constants of the new complexes have been evaluated by the 1H NMR or fluorescent titration methods. [Copyright &y& Elsevier]