Triply stranded metallo-supramolecular helicate based on triptycene with efficient encapsulation to bulky guest molecules

2022 ◽  
Author(s):  
Xu-Sheng Du ◽  
Ying Han ◽  
Chuan-Feng Chen
Keyword(s):  
Building Blocks ◽  
Guest Molecules

Triply stranded metallo-supramolecular helicates were readily constructed via the coordination of Gallium (III) cation and ligands based on 2,7- and 2,6-disubstituted triptycenes. The significance of building blocks in the construction...

Metal-Organic Frameworks for Asymmetric Catalysis and Chiral Separations

MRS Bulletin ◽  
2007 ◽  
Vol 32 (7) ◽  
pp. 544-548 ◽  
Author(s):  
Wenbin Lin
Keyword(s):  
Asymmetric Catalysis ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Chiral Separations ◽  
Bridging Ligands ◽  
Guest Molecules ◽  
Pure Compounds ◽  
Metal Organic

Metal-organic frameworks (MOFs) are an interesting class of molecule-based hybrid materials built from metal-connecting points and bridging ligands. MOFs have received much attention, owing to their potential impact on many technological areas, including gas storage, separation, and heterogeneous catalysis. The modular nature of MOFs endows them with facile tunability, and as a result, properly designed MOFs can yield ideal heterogeneous catalysts with uniform active sites through judicious choice of the building blocks. Homochiral MOFs, which can be prepared by numerous approaches (construction from achiral components by seeding with a chiral single crystal, templating with coordinating chiral co-ligands, and building from metal-connecting nodes and chiral bridging ligands), represent a unique class of materials for the economical production of optically pure compounds, whether through asymmetric catalysis or enantioselective inclusion of chiral guest molecules in their porous frameworks. As such, homochiral MOFs promise new opportunities for developing chirotechnology. This contribution provides a brief overview of recent progress in the synthesis of homochiral porous MOFs and their applications in asymmetric catalysis and chiral separations.

scholarly journals Inducing Social Self-Sorting in Organic Cages to Tune the Shape of the Internal Cavity

2020 ◽  
Author(s):  
Valentina Abet ◽  
Filip Szczypiński ◽  
Marc Little ◽  
Valentina Santolini ◽  
Christopher D. Jones ◽  
...  
Keyword(s):  
Computational Models ◽  
Computational Prediction ◽  
Building Blocks ◽  
Internal Cavity ◽  
High Symmetry ◽  
Social Self ◽  
Guest Molecules ◽  
The Stability ◽  
Surface Chemistries ◽  
Low Symmetry

<p>Many interesting target guest molecules have low symmetry, yet most methods for synthesising hosts result in highly symmetrical capsules. Methods of generating lower-symmetry pores are thus required to maximise the binding affinity in host-guest complexes. Here, we use mixtures of tetraaldehyde building blocks to access low-symmetry imine cages. Whether a low-energy cage is isolated can be correctly predicted from the thermodynamic preference observed in computational models. The stability of the observed structures depends on the geometrical match of the aldehyde building blocks. One bent aldehyde stands out as unable to assemble into high-symmetry cages—and the same aldehyde generates low-symmetry socially self-sorted cages when combined with a linear aldehyde. We exploit this finding to synthesise a family of low-symmetry cages containing heteroatoms, illustrating that pores of varying geometries and surface chemistries may be reliably accessed through computational prediction and self-sorting.</p>

scholarly journals Computational Exploration of Functionalized Rhombellanes: Building Blocks and Double-Shell Structures

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 343 ◽  
Author(s):  
Katalin Nagy ◽  
Beata Szefler ◽  
Csaba L. Nagy
Keyword(s):  
Density Functional ◽  
Molecular Design ◽  
Drug Carrier ◽  
Geometry Optimization ◽  
Molecular Geometry ◽  
Building Blocks ◽  
Great Promise ◽  
Molecular Symmetry ◽  
Guest Molecules ◽  
Computational Exploration

Double-shell covalent assemblies with the framework of the cube–rhombellane were recently proposed as potential drug delivery systems. Their potential to encapsulate guest molecules combined with appropriate surface modifications show great promise to meet the prerequisites of a drug carrier. This work reports the molecular design of such clusters with high molecular symmetry, as well as the evaluation of the geometric and electronic properties using density functional theory. The computational studies of the double-shell assemblies and their corresponding building blocks were conducted using the B3LYP/6-31G(d,p) method as implemented in Gaussian 09. The results show that the assembly of the building blocks is energetically favorable, leading to clusters with higher stability than the corresponding shell fragments, with large HOMO–LUMO gap values. In case of aromatic systems, interlayer stacking interactions between benzene rings contribute to the molecular geometry and stability. During geometry optimization the clusters preserve the high molecular symmetry of the building blocks.

scholarly journals Inducing Social Self-Sorting in Organic Cages to Tune the Shape of the Internal Cavity

2020 ◽  
Author(s):  
Valentina Abet ◽  
Filip Szczypiński ◽  
Marc Little ◽  
Valentina Santolini ◽  
Christopher D. Jones ◽  
...  
Keyword(s):  
Computational Models ◽  
Computational Prediction ◽  
Building Blocks ◽  
Internal Cavity ◽  
High Symmetry ◽  
Social Self ◽  
Guest Molecules ◽  
The Stability ◽  
Surface Chemistries ◽  
Low Symmetry

<p>Many interesting target guest molecules have low symmetry, yet most methods for synthesising hosts result in highly symmetrical capsules. Methods of generating lower-symmetry pores are thus required to maximise the binding affinity in host-guest complexes. Here, we use mixtures of tetraaldehyde building blocks to access low-symmetry imine cages. Whether a low-energy cage is isolated can be correctly predicted from the thermodynamic preference observed in computational models. The stability of the observed structures depends on the geometrical match of the aldehyde building blocks. One bent aldehyde stands out as unable to assemble into high-symmetry cages—and the same aldehyde generates low-symmetry socially self-sorted cages when combined with a linear aldehyde. We exploit this finding to synthesise a family of low-symmetry cages containing heteroatoms, illustrating that pores of varying geometries and surface chemistries may be reliably accessed through computational prediction and self-sorting.</p>

scholarly journals Two-dimensional self-assemblies of telechelic organic compounds: structure and surface host–guest chemistry

2013 ◽  
Vol 371 (2000) ◽  
pp. 20120302 ◽  
Author(s):  
Hui-Juan Yan ◽  
Jia Liu ◽  
Dong Wang ◽  
Li-Jun Wan
Keyword(s):  
Hydrogen Bond ◽  
Self Assembly ◽  
Pyrolytic Graphite ◽  
Building Blocks ◽  
Carboxyl Groups ◽  
Two Dimensional ◽  
Guest Molecules ◽  
Surface And Interface ◽  
Trimesic Acid ◽  
Application Fields

Guiding the self-assembly of different types of functional molecules into well-defined structures on surfaces is beneficial for both fundamental surface and interface study and emerging application fields, especially molecular and organic electronics. This review focuses on understanding the two-dimensional self-assembly process of telechelic organics, which feature alkoxylene chains terminated with carboxyl groups. With the combined flexibility of alkyl chains and directionality of carboxyl groups, telechelic organics show unique assembly behaviour on two-dimensional surfaces. By increasing the length of the alkoxylene chains, the cavities in the nanoporous networks of telechelic trimesic acid (1,3,5-benzene tricarboxylic acid) derivatives change from hexagonal cavities to irregular cavities on a highly oriented pyrolytic graphite surface. The nanoporous networks provide a flexible host template for host–guest supramolecular chemistry because the cavities framed by the flexible alkoxylene chains can be changed in accordance with the sizes/shapes of the guest molecules. Furthermore, the terminal carboxylic group can form a hydrogen bond with another hydrogen bond partner, leading to multi-component structural motifs and hierarchical assemblies. The unique assembly behaviour of telechelic organics makes them promising structures as important building blocks for the design and construction of complex self-assembled nanoarchitectures.

Hydrogen bonded frameworks: smart materials used smartly

2021 ◽  
Author(s):  
Anna Yusov ◽  
Alexandra M. Dillon ◽  
Michael D. Ward
Keyword(s):  
Smart Materials ◽  
Building Blocks ◽  
Guest Molecules ◽  
Molecular Building Blocks ◽  
Wide Range ◽  
Key Technologies ◽  
Materials Used ◽  
Hydrogen Bonded

Hydrogen-bonded host frameworks constructed from carefully selected molecular building blocks can exhibit architectures capable of encapsulating a wide range of guest molecules, with promising opportunities in key technologies.

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

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