Lamellar Bridged Silsesquioxanes: Self-Assembly through a Combination of Hydrogen Bonding and Hydrophobic Interactions

2005 ◽  
Vol 11 (5) ◽  
pp. 1527-1537 ◽  
Author(s):  
Joël J. E. Moreau ◽  
Luc Vellutini ◽  
Michel Wong Chi Man ◽  
Catherine Bied ◽  
Philippe Dieudonné ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Hydrophobic Interactions ◽  
Bridged Silsesquioxanes

scholarly journals Hydrophobic interactions control the self-assembly of DNA and cellulose

2021 ◽  
Vol 54 ◽  
Author(s):  
Björn Lindman ◽  
Bruno Medronho ◽  
Luís Alves ◽  
Magnus Norgren ◽  
Lars Nordenskiöld
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Hydrophobic Interactions ◽  
Double Helix ◽  
The Self ◽  
Biological Macromolecules ◽  
Helix Formation ◽  
Assembly Features ◽  
Pertinent Information ◽  
Net Charges

Abstract Desoxyribosenucleic acid, DNA, and cellulose molecules self-assemble in aqueous systems. This aggregation is the basis of the important functions of these biological macromolecules. Both DNA and cellulose have significant polar and nonpolar parts and there is a delicate balance between hydrophilic and hydrophobic interactions. The hydrophilic interactions related to net charges have been thoroughly studied and are well understood. On the other hand, the detailed roles of hydrogen bonding and hydrophobic interactions have remained controversial. It is found that the contributions of hydrophobic interactions in driving important processes, like the double-helix formation of DNA and the aqueous dissolution of cellulose, are dominating whereas the net contribution from hydrogen bonding is small. In reviewing the roles of different interactions for DNA and cellulose it is useful to compare with the self-assembly features of surfactants, the simplest case of amphiphilic molecules. Pertinent information on the amphiphilic character of cellulose and DNA can be obtained from the association with surfactants, as well as on modifying the hydrophobic interactions by additives.

scholarly journals Experimentally-Determined Strengths of Atom-Atom (C, N, O) Interactions Responsible for Protein Self-Assembly in Water: Applications to Folding and Other Protein Processes

2020 ◽  
Author(s):  
Xian Cheng ◽  
Irina A. Shkel ◽  
Kevin O’Connor ◽  
M. Thomas Record
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Aromatic Compounds ◽  
Hydrophobic Interactions ◽  
Unit Area ◽  
Lone Pair ◽  
Quantitative Information ◽  
Chemical Effects ◽  
Protein Interfaces ◽  
Polypeptide Backbone

AbstractFolding and other protein self-assembly processes are driven by favorable interactions between O, N, and C unified atoms of the polypeptide backbone and sidechains. These processes are perturbed by solutes that interact with these atoms differently than water does. C=O···HN hydrogen bonding and various π-system interactions have been better-characterized structurally or by simulations than experimentally in water, and unfavorable interactions are relatively uncharacterized. To address this situation, we previously quantified interactions of alkylureas with amide and aromatic compounds, relative to interactions with water. Analysis yielded strengths of interaction of each alkylurea with unit areas of different hybridization states of unified O, N, C atoms of amide and aromatic compounds. Here, by osmometry, we quantify interactions of ten pairs of amides selected to complete this dataset. A novel analysis yields intrinsic strengths of six favorable and four unfavorable atom-atom interactions, expressed per unit area of each atom and relative to interactions with water. The most favorable interactions are sp2O - sp2C (lone pair-π, presumably n-π*), sp2C - sp2C (π-π and/or hydrophobic), sp2O-sp2N (hydrogen bonding) and sp3C-sp2C (CH-π and/or hydrophobic). Interactions of sp3C with itself (hydrophobic) and with sp2N are modestly favorable, while sp2N interactions with sp2N and with amide/aromatic sp2C are modestly unfavorable. Amide sp2O-sp2O interactions and sp2O-sp3C interactions are more unfavorable, indicating the preference of amide sp2O to interact with water. These intrinsic interaction strengths are used to predict interactions of amides with proteins and chemical effects of amides (including urea, N-ethylpyrrolidone (NEP), and polyvinyl-pyrrolidone (PVP)) on protein stability.SignificanceQuantitative information about strengths of amide nitrogen-amide oxygen hydrogen bonds and π-system and hydrophobic interactions involving amide-context sp2 and/or sp3 carbons is needed to assess their contributions to specificity and stability of protein folds and assemblies in water, as well as to predict or interpret how urea and other amides interact with proteins and affect protein processes. Here we obtain this information from thermodynamic measurements of interactions between small amide molecules in water and a novel analysis that determines intrinsic strengths of atom-atom interactions, relative to water and per unit area of each atom-type present in amide compounds. These findings allow prediction or interpretation of effects of any amide on protein processes from structure, and may be useful to analyze protein interfaces.

scholarly journals Experimentally determined strengths of favorable and unfavorable interactions of amide atoms involved in protein self-assembly in water

2020 ◽  
Vol 117 (44) ◽  
pp. 27339-27345 ◽  
Author(s):  
Xian Cheng ◽  
Irina A. Shkel ◽  
Kevin O’Connor ◽  
M. Thomas Record
Keyword(s):  
Hydrogen Bonding ◽  
Protein Stability ◽  
Water Analysis ◽  
Self Assembly ◽  
Aromatic Compounds ◽  
Hydrophobic Interactions ◽  
Unit Area ◽  
Lone Pair ◽  
Chemical Effects ◽  
Polypeptide Backbone

Folding and other protein self-assembly processes are driven by favorable interactions between O, N, and C unified atoms of the polypeptide backbone and side chains. These processes are perturbed by solutes that interact with these atoms differently than water does. Amide NH···O=C hydrogen bonding and various π-system interactions have been better characterized structurally or by simulations than experimentally in water, and unfavorable interactions are relatively uncharacterized. To address this situation, we previously quantified interactions of alkyl ureas with amide and aromatic compounds, relative to interactions with water. Analysis yielded strengths of interaction of each alkylurea with unit areas of different hybridization states of unified O, N, and C atoms of amide and aromatic compounds. Here, by osmometry, we quantify interactions of 10 pairs of amides selected to complete this dataset. An analysis yields intrinsic strengths of six favorable and four unfavorable atom−atom interactions, expressed per unit area of each atom and relative to interactions with water. The most favorable interactions are sp2O−sp2C (lone pair−π, presumablyn−π*), sp2C−sp2C (π−π and/or hydrophobic), sp2O−sp2N (hydrogen bonding) and sp3C−sp2C (CH−π and/or hydrophobic). Interactions of sp3C with itself (hydrophobic) and with sp2N are modestly favorable, while sp2N interactions with sp2N and with amide/aromatic sp2C are modestly unfavorable. Amide sp2O−sp2O interactions and sp2O−sp3C interactions are more unfavorable, indicating the preference of amide sp2O to interact with water. These intrinsic interaction strengths are used to predict interactions of amides with proteins and chemical effects of amides (including urea,N-ethylpyrrolidone [NEP], and polyvinylpyrrolidone [PVP]) on protein stability.

scholarly journals Self-Assembled Bimetallic Aluminum-Salen Catalyst for the Cyclic Carbonates Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4097
Author(s):  
Wooyong Seong ◽  
Hyungwoo Hahm ◽  
Seyong Kim ◽  
Jongwoo Park ◽  
Khalil A. Abboud ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Reaction Pathway ◽  
Kinetic Studies ◽  
Cyclic Carbonate ◽  
Reaction Conditions ◽  
Formation Reaction ◽  
X Ray ◽  
Carbonate Formation ◽  
Salen Aluminum

Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO2. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) of the bis-urea salen Al catalyst is three times higher than that of a μ-oxo-bridged catalyst, and 13 times higher than that of a monomeric salen aluminum catalyst. The bimetallic reaction pathway is suggested based on urea additive studies and kinetic studies. Additionally, the X-ray crystal structure of a bis-urea salen Ni complex supports the self-assembly of the bis-urea salen metal complex through hydrogen bonding.

scholarly journals Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4705
Author(s):  
Boer Liu ◽  
Xi Chen ◽  
Glenn A. Spiering ◽  
Robert B. Moore ◽  
Timothy E. Long
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Microphase Separation ◽  
Triblock Copolymers ◽  
Random Copolymer ◽  
Thermomechanical Properties ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Central Block ◽  
Quadruple Hydrogen Bonding

This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.

Recording the Self-Assembly Behavior of Nanomaterials Directed by Hydrogen Bonding

2021 ◽  
Author(s):  
Ganghuo Pan ◽  
Jie Leng ◽  
Liye Deng ◽  
Liwen Xing ◽  
Rui Feng
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
The Self ◽  
Assembly Behavior

Self-assembly of CdSe/CdS quantum dots by hydrogen bonding on Au surfaces for photoreception

2003 ◽  
pp. 2278 ◽  
Author(s):  
Jing Tang ◽  
Henrik Birkedal ◽  
Eric W. McFarland ◽  
Galen D. Stucky
Keyword(s):  
Quantum Dots ◽  
Hydrogen Bonding ◽  
Self Assembly ◽  
Cds Quantum Dots

Self-assembly of 2,6-dimethylpyridine on Cu(110) directed by weak hydrogen bonding

2007 ◽  
Vol 601 (16) ◽  
pp. L91-L94 ◽  
Author(s):  
Junseok Lee ◽  
Daniel B. Dougherty ◽  
John T. Yates
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Weak Hydrogen Bonding

Hydrogen-Bonding Layer Protecting Polyelectrolyte Capsules and Its Mechanical Property Study with Atomic Force Microscope

2008 ◽  
Vol 8 (6) ◽  
pp. 2996-3002 ◽  
Author(s):  
Liqin Ge ◽  
Xing Wang ◽  
Long Ba ◽  
Zhongze Gu
Keyword(s):  
Hydrogen Bonding ◽  
Atomic Force Microscope ◽  
Elastic Deformation ◽  
Self Assembly ◽  
Laser Scanning ◽  
Confocal Laser ◽  
Bonding Layer ◽  
Layer By Layer ◽  
Assembly Method ◽  
Atomic Force

The hydrogen-bonding multilayered polyelectrolyte capsules with sizes around 6 μm were fabricated by layer-by-layer self-assembly method. The morphology of the obtained capsules was observed with Scanning Electron Microscope (SEM), Confocal Laser Scanning Microscope (CLSM) and Atomic Force Microscope (AFM), respectively. The elastic properties of the capsules were studied with AFM. The capsule was pressed by cantilever with different lengths, a glass bead glued at the end of the cantilever. The force curves were measured on the capsule in air. The Young's modulus of the capsule was obtained (E = 170 MPa for the loading). Results show that this model can predict the elastic deformation of the microcapsule. The accuracy of the elastic deformation of polymer capsule can be ensured using a cantilever of mediate stiffness. Our results show that the existence of the hydrogen-bonding layer makes the multilayered polyelectrolyte harder in comparison with the pure multilayered polyelectrolyte capsules.

Photoluminescence of Eu(iii)-doped lamellar bridged silsesquioxanes self-templated through a hydrogen bonding array

2008 ◽  
Vol 18 (35) ◽  
pp. 4172 ◽  
Author(s):  
Sónia S. Nobre ◽  
Carlos D. S. Brites ◽  
Rute A. S. Ferreira ◽  
Verónica de Zea Bermudez ◽  
Carole Carcel ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Bridged Silsesquioxanes
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