Self-assembly of a Si-based cage by the formation of 24 equivalent covalent bonds

2018 ◽  
Vol 54 (84) ◽  
pp. 11877-11880 ◽  
Author(s):  
Jessica L. Holmes ◽  
Brendan F. Abrahams ◽  
Anna Ahveninen ◽  
Berin A. Boughton ◽  
Timothy A. Hudson ◽  
...  
Keyword(s):  
Self Assembly ◽  
Covalent Bonds

A covalent, robust, nano-sized tetrahedral cage containing six silicon centres has been synthesised and structurally characterised.

scholarly journals Formation of Au-Silane Bonds

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Shira Yochelis ◽  
Eran Katzir ◽  
Yoav Kalcheim ◽  
Vitaly Gutkin ◽  
Oded Millo ◽  
...  
Keyword(s):  
Molecular Electronics ◽  
Self Assembly ◽  
Au Nanoparticles ◽  
Electrical Coupling ◽  
Gold Surface ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Fundamental Study ◽  
Covalent Bonds ◽  
Anchoring Groups

Many intriguing aspects of molecular electronics are attributed to organic-inorganic interactions, yet charge transfer through such junctions still requires fundamental study. Recently, there is a growing interest in anchoring groups, which considered dominating the charge transport. With this respect, we choose to investigate self-assembly of disilane molecules sandwiched between gold surface and gold nanoparticles. These assemblies are found to exhibit covalent bonds not only between the anchoring Si groups and the gold surfaces but also in plane crosslinks that increase the monolayer stability. Finally, using scanning tunneling spectroscopy we demonstrate that the disilane molecules provide strong electrical coupling between the Au nanoparticles and a superconductor substrate.

scholarly journals Pillararenes Trimer for Self-Assembly

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 651 ◽  
Author(s):  
Huacheng Zhang ◽  
Zhaona Liu ◽  
Hui Fu
Keyword(s):  
Self Assembly ◽  
Driving Forces ◽  
Click Reaction ◽  
Noncovalent Interactions ◽  
Coupling Reaction ◽  
Covalent Bonds ◽  
Guest Molecules ◽  
Palladium Catalyzed ◽  
Noncovalent Bonds ◽  
External Stimuli

Pillararenes trimer with particularly designed structural geometry and excellent capacity of recognizing guest molecules is a very efficient and attractive building block for the fabrication of advanced self-assembled materials. Pillararenes trimers could be prepared via both covalent and noncovalent bonds. The classic organic synthesis reactions such as click reaction, palladium-catalyzed coupling reaction, amidation, esterification, and aminolysis are employed to build covalent bonds and integrate three pieces of pillararenes subunits together into the “star-shaped” trimers and linear foldamers. Alternatively, pillararenes trimers could also be assembled in the form of host-guest inclusions and mechanically interlocked molecules via noncovalent interactions, and during those procedures, pillararenes units contribute the cavity for recognizing guest molecules and act as a “wheel” subunit, respectively. By fully utilizing the driving forces such as host-guest interactions, charge transfer, hydrophobic, hydrogen bonding, and C–H…π and π–π stacking interactions, pillararenes trimers-based supramolecular self-assemblies provide a possibility in the construction of multi-dimensional materials such as vesicular and tubular aggregates, layered networks, as well as frameworks. Interestingly, those assembled materials exhibit interesting external stimuli responsiveness to e.g., variable concentrations, changed pH values, different temperature, as well as the addition/removal of competition guests and ions. Thus, they could further be used for diverse applications such as detection, sorption, and separation of significant multi-analytes including metal cations, anions, and amino acids.

Template-Directed Syntheses of Catenanes

1997 ◽  
Vol 62 (4) ◽  
pp. 527-557 ◽  
Author(s):  
Martin Bělohradský ◽  
Françisco M. Raymo ◽  
J. Fraser Stoddart
Keyword(s):  
Self Assembly ◽  
Molecular Level ◽  
Covalent Bonds ◽  
Topological Features ◽  
Multistep Synthesis ◽  
Chance Event ◽  
Degree Of Control ◽  
High Degree ◽  
Acyclic Precursor ◽  
Molecular Compounds

The art and science of introducing mechanical-interlocking at the molecular level in order to generate catenanes - molecules composed of two or more macrocyclic components - offers the opportunity of constructing a new range of molecular compounds possessing intriguing properties. However, the topological features displayed by catenanes has rendered the syntheses of such molecular compounds an extremely challenging task for synthetic chemists to address. Their early syntheses were based upon either statistical approaches - the threading of a small amount of a macrocycle on to an acyclic precursor as a chance event - or directed approaches, relying upon the temporary introduction of covalent bonds in the multistep synthesis of a so-called precatenane, followed by its conversion ultimately into a catenane. These approaches afforded catenanes in very low yields overall and only after following tedious and laborious synthetic procedures. Fortunately, however, with the advent of supramolecular chemistry, template-directed methods that allow us to self-assemble [n]catenanes much more efficiently have become available. Numerous successful template-directed syntheses have now emerged - some by chance and others by design. These methods have been based upon (i) metal coordinating, (ii) hydrogen bonding, (iii) solvophobic, and/or (iv) π-π stacking interactions which have been found to govern self-assembly processes to catenated compounds from appropriate precursors. Their relative simplicity, the high degree of control with which they can be employed, and the remarkable efficiency with which they proceed has already provided the opportunity to synthetic chemists to self-assemble a series of [n]catenanes, incorporating from two up to five mechanically-interlocked macrocyclic components.

scholarly journals Self-assembly of a “double dynamic covalent” amphiphile featuring a glucose-responsive imine bond

2016 ◽  
Vol 52 (43) ◽  
pp. 6981-6984 ◽  
Author(s):  
Xin Wu ◽  
Xuan-Xuan Chen ◽  
Miao Zhang ◽  
Zhao Li ◽  
Philip A. Gale ◽  
...  
Keyword(s):  
Self Assembly ◽  
Covalent Bonds ◽  
Imine Bond

Glucose recognition via in situ formation of supramolecular vesicular aggregates that involve two dynamic covalent bonds.

scholarly journals Pillararenes Trimer for Self-Assembly

2020 ◽  
Author(s):  
Huacheng Zhang
Keyword(s):  
Self Assembly ◽  
Driving Forces ◽  
Click Reaction ◽  
Noncovalent Interactions ◽  
Coupling Reaction ◽  
Covalent Bonds ◽  
Guest Molecules ◽  
Palladium Catalyzed ◽  
Noncovalent Bonds ◽  
External Stimuli

Pillararenes trimer with particularly designed structural geometry and excellent capacity of recognizing guest molecules is a very efficient and attractive building block for the fabrication of advanced self-assembled materials. Pillararenes trimers could be prepared via both covalent and noncovalent bonds. The classic organic synthesis reactions such as click reaction, Palladium-catalyzed coupling reaction, amidation, esterification and aminolysis are employed to build covalent bonds and integrate three pieces of pillararenes subunits together into the “star-shaped” trimers and linear foldamers. Alternatively, pillararenes trimers could also be assembled in the form of host-guest inclusions and mechanically interlocked molecules via noncovalent interactions, and during those procedures, pillararenes units contribute the cavity for recognizing guest molecules and act as a “wheel” subunit, respectively. By fully utilizing the driving forces such as host-guest interactions, charge transfer, hydrophobic, hydrogen bonding, C—H…π and π—π stacking interactions, pillararenes trimers-based supramolecular self-assemblies provide a possibility in the construction of multi-dimensional materials such as vesicular and tubular aggregates, layered networks, as well as frameworks. Interestingly, those assembled materials exhibit interesting external stimuli responsiveness to e.g., variable concentrations, changed pH values, different temperature, as well as the addition/removal of competition guests and ions. Thus, they could further be used for diverse applications such as detection, sorption and separation of significant multi-analytes including metal cations, anions and amino acids.

Using reversible non-covalent and covalent bonds to create assemblies and equilibrating molecular networks that survive 5 molar urea

2019 ◽  
Vol 17 (8) ◽  
pp. 2081-2086 ◽  
Author(s):  
Meagan A. Beatty ◽  
Aidan T. Pye ◽  
Alok Shaurya ◽  
Belim Kim ◽  
Allison J. Selinger ◽  
...  
Keyword(s):  
Self Assembly ◽  
Noncovalent Interactions ◽  
Molecular Networks ◽  
Covalent Bonds ◽  
Reversible Covalent

Molecules that assemble through reversible covalent and noncovalent interactions achieve self-assembly at extreme levels of urea and NaCl.

scholarly journals Mapping the Mechanical Properties of Hierarchical Supercrystalline Ceramic-Organic Nanocomposites

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4790 ◽  
Author(s):  
Büsra Bor ◽  
Lydia Heilmann ◽  
Berta Domènech ◽  
Michael Kampferbeck ◽  
Tobias Vossmeyer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Organic Phase ◽  
Self Assembly ◽  
Organic Content ◽  
Treatment Temperature ◽  
Covalent Bonds ◽  
Soft Phase ◽  
Beneficial Effects ◽  
Ceramic Nanoparticles

Multiscale ceramic-organic supercrystalline nanocomposites with two levels of hierarchy have been developed via self-assembly with tailored content of the organic phase. These nanocomposites consist of organically functionalized ceramic nanoparticles forming supercrystalline micron-sized grains, which are in turn embedded in an organic-rich matrix. By applying an additional heat treatment step at mild temperatures (250–350 °C), the mechanical properties of the hierarchical nanocomposites are here enhanced. The heat treatment leads to partial removal and crosslinking of the organic phase, minimizing the volume occupied by the nanocomposites’ soft phase and triggering the formation of covalent bonds through the organic ligands interfacing the ceramic nanoparticles. Elastic modulus and hardness up to 45 and 2.5 GPa are attained, while the hierarchical microstructure is preserved. The presence of an organic phase between the supercrystalline grains provides a toughening effect, by curbing indentation-induced cracks. A mapping of the nanocomposites’ mechanical properties reveals the presence of multiple microstructural features and how they evolve with heat treatment temperature. A comparison with non-hierarchical, homogeneous supercrystalline nanocomposites with lower organic content confirms how the hierarchy-inducing organic excess results in toughening, while maintaining the beneficial effects of crosslinking on the materials’ stiffness and hardness.

Synthesis of dynamic imine macrocyclic supramolecular polymers via synchronized self-assembly based on dynamic covalent bonds and noncovalent interactions

2020 ◽  
Vol 56 (65) ◽  
pp. 9288-9291 ◽  
Author(s):  
Zhenfeng He ◽  
Yufeng Huo ◽  
Chao Wang ◽  
Duo Pan ◽  
Binbin Dong ◽  
...  
Keyword(s):  
Self Assembly ◽  
Noncovalent Interactions ◽  
Single Step ◽  
The Self ◽  
Supramolecular Polymers ◽  
Aggregation Process ◽  
Covalent Bonds

The preparation of host imine macrocycles and the self-assembly aggregation process are merged into one single step for self-assembly to form dynamic imine macrocyclic supramolecular polymers.

Sign in / Sign up

Export Citation Format

Share Document