Folding and self-assembly of aromatic and aliphatic urea oligomers: Towards connecting structure and function

Fischer, Lucile; Guichard, Gilles

doi:10.1039/c001090a

Cited by 118 publications

(75 citation statements)

References 184 publications

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“…To investigate the effect of hydrogen bonding on the self‐assembly on the highly oriented pyrolytic graphite (HOPG) surface, a series of amide derivatives 1 a – 3 a and urea derivatives 1 u – 3 u were designed and synthesized (Figure , see the Supporting Information for synthetic details). Since the hydrogen bond via a urea group is intrinsically stronger than that of an amide group, the molecular orderings composed of urea derivatives are expected to be more stable than those of amide derivatives . Compounds 3 a and 3 u have alkyl side chains with different lengths (i.e., hexadecyl and octyl) at each end of the biphenyl core moiety.…”

Section: Resultsmentioning

confidence: 99%

Investigation on the Surface‐Confined Self‐Assembly Stabilized by Hydrogen Bonds of Urea and Amide Groups: Quantitative Analysis of Concentration Dependence of Surface Coverage

Nishitani

Hirose

Matsuda

2015

Chemistry An Asian Journal

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Formation of a hydrogen-bond network via an amide group is a key driving force for the nucleation-elongation-type self-assembly that is often seen in biomolecules and artificial supramolecular assemblies. In this work, rod-coil-like aromatic compounds bearing an amide (1 a-3 a) or urea group (1 u-3 u) were synthesized, and their self-assemblies on a 2-D surface were investigated by scanning tunneling microscopy (STM). According to the quantitative analysis of the concentration dependence of the surface coverage, it was revealed that the strength of the hydrogen bond (i.e., amide or urea) and the number of non-hydrogen atoms in a molecular component (i.e., size of core and length of alkyl side chain) play a primary role in determining the stabilization energy during nucleation and elongation processes of molecular ordering on the HOPG surface.

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Section: Resultsmentioning

confidence: 99%

Investigation on the Surface‐Confined Self‐Assembly Stabilized by Hydrogen Bonds of Urea and Amide Groups: Quantitative Analysis of Concentration Dependence of Surface Coverage

Nishitani

Hirose

Matsuda

2015

Chemistry An Asian Journal

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“…[13,14] In this work, we propose to use the oxo to thioxo (or selenoxo) substitution to interrogate the structure and function of foldamers [15] made of urea linkages instead of amide bonds. [16,17] Oligoureas consisting of chiral ethylene diamine units connected by a carbonyl group are known to adopt a regular helical structure (2.5-helix) maintained by a network of three centered hydrogen bonds closing 12-and 14-membered pseudocycles.…”

Section: Introductionmentioning

confidence: 99%

Isosteric Substitutions of Urea to Thiourea and Selenourea in Aliphatic Oligourea Foldamers: Site‐Specific Perturbation of the Helix Geometry

Nelli

Antunes

Salaün

et al. 2014

Chemistry A European J

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Nearly isosteric oxo to thioxo substitution was employed to interrogate the structure of foldamers with a urea backbone and explore the relationship between helical folding and hydrogen-bonding interactions. A series of oligomers with urea bonds substituted by thiourea bonds at discrete or all positions in the sequence have been prepared and their folding propensity was studied by using a combination of spectroscopic methods and X-ray diffraction. The outcome of oxo to thioxo replacements on the helical folding was found to depend on whether central or terminal ureas were modified. The canonical helix geometry was not affected upon insertion of thioureas close to the negative end of the helix dipole, whereas thioureas close to the positive pole were found to increase the terminal flexibility and cause helix fraying. Perturbation was amplified when a selenourea was incorporated instead, leading to a structure that is only partly folded.

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“…Computational methods were employed in order to get a better insight into proton dissociation processes and anion binding, mainly from the structural viewpoint. Parent bis‐urea compounds 1 H 2 and 5 H 2 as well as their mono‐ and dianions have been modeled by using the ( trans , trans ) conformation of the urea parts, which is the accepted conformation for N , N ′‐diarylureas with NH‐C(=O)‐NH cores . We note that the trans / cis nomenclature is used for the conformations of N , N ′‐diarylurea bonds, based on the spatial relationship between N‐aryl group and carbonyl oxygen atom.…”

Section: Methodsmentioning

confidence: 99%

Protonation and Anion Binding Properties of Aromatic Bis‐Urea Derivatives—Comprehending the Proton Transfer

Barišić

Cindro

Kulcsár

et al. 2019

Chemistry A European J

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A series of aromatic bis‐urea derivatives was prepared and their proton dissociation, as well as anion binding properties in DMSO were investigated. To this end, UV/Vis and 1H NMR spectroscopies and computational methods were employed. The synthesized molecules differed in the relative position of the urea moieties (ortho‐ and meta‐derivatives) and in the functional groups (−H, −CH3, −OCH3, −NO2) in the para‐position of the pendant phenyl groups. Remarkably high acidities of the compounds (logK1H≈14), were ascribed primarily to the stabilizing effect of the aromatic subunits. Quantum chemical calculations corroborated the conclusions drawn from experimental data and provided information from the structural point of view. Knowledge regarding protonation properties proved to be essential for reliable quantitative determination of anion binding affinities. Studied receptors were selective for acetate and dihydrogen phosphate among several anions. Formation of their complexes of 1:1 and 1:2 (ligand/anion) stoichiometries was quantitatively characterized. Proton transfer was taken into account in the course of data analysis, which was especially important in the case of AcO−. ortho‐Receptors were proven to be more efficient acetate binders, achieving coordination with all four NH groups. The meta‐analogues preferred dihydrogen phosphate, which acted as both hydrogen bond donor and acceptor. Cooperative binding was detected in the case of 1:2 H2PO4− complexes, which was assigned to formation of interanionic hydrogen bonds.

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Folding and self-assembly of aromatic and aliphatic urea oligomers: Towards connecting structure and function

Cited by 118 publications

References 184 publications

Investigation on the Surface‐Confined Self‐Assembly Stabilized by Hydrogen Bonds of Urea and Amide Groups: Quantitative Analysis of Concentration Dependence of Surface Coverage

Investigation on the Surface‐Confined Self‐Assembly Stabilized by Hydrogen Bonds of Urea and Amide Groups: Quantitative Analysis of Concentration Dependence of Surface Coverage

Isosteric Substitutions of Urea to Thiourea and Selenourea in Aliphatic Oligourea Foldamers: Site‐Specific Perturbation of the Helix Geometry

Protonation and Anion Binding Properties of Aromatic Bis‐Urea Derivatives—Comprehending the Proton Transfer

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