scholarly journals Covalently Templated Syntheses of Mechanically Interlocked Molecules

Synthesis ◽  
2021 ◽  
Author(s):  
Jan van Maarseveen ◽  
Milo Dinu Cornelissen ◽  
Simone Pilon
Keyword(s):  
Drug Discovery ◽  
Potential Application ◽  
Molecular Machines ◽  
Stimuli Responsive ◽  
Interlocked Molecules ◽  
Future Developments ◽  
Mechanical Bond ◽  
Non Covalent Interactions ◽  
Covalent Interactions ◽  
Rotational Freedom

Mechanically interlocked molecules (MiMs) such as catenanes and rotaxanes exhibit unique properties due to the mechanical bond which unites their components. The translational and rotational freedom present in these compounds may be harnessed to create stimuli-responsive MiMs, which find potential application as artificial molecular machines. Mechanically interlocked structures such as lasso peptides have also been found in nature, making MiMs promising albeit elusive targets for drug discovery. Although the first syntheses of MiMs were based on covalent strategies, approaches based on non-covalent interactions rose to prominence thereafter and have remained dominant. Non-covalent strategies are generally short and efficient, but do require particular structural motifs which are difficult to alter. In a covalent approach, MiMs can be more easily modified while the components may have increased rotational and translational freedom. Both approaches have complementary merits and combining the unmatched efficiency of non-covalent approaches with the scope of covalent syntheses may open up vast opportunities. In this review, recent covalently templated syntheses of MiMs are discussed to show their complementarity and anticipate future developments in this field.

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

2019 ◽  
Author(s):  
Andrew Heard ◽  
Stephen Goldup
Keyword(s):  
Active Site ◽  
Molecular Machines ◽  
Enantioselective Catalysis ◽  
Interlocked Molecules ◽  
End Groups ◽  
Mechanical Bond

<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

Multi-responsive polyethylene-polyamine/gelatin hydrogel induced by non-covalent interactions

RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 48661-48665 ◽  
Author(s):  
Zhidong Zhang ◽  
Yingxin Liu ◽  
Xin Chen ◽  
Zhengzhong Shao
Keyword(s):  
Aqueous Solution ◽  
Stimuli Responsive ◽  
Gelatin Hydrogel ◽  
Polyethylene Polyamine ◽  
Non Covalent Interactions ◽  
Covalent Interactions

By simply introducing a gelatin aqueous solution, the polyethylene-polyamine (PPA)/gelatin hydrogel with multi-stimuli-responsive properties was obtained.

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

2019 ◽  
Author(s):  
Andrew Heard ◽  
Stephen Goldup
Keyword(s):  
Active Site ◽  
Molecular Machines ◽  
Enantioselective Catalysis ◽  
Interlocked Molecules ◽  
End Groups ◽  
Mechanical Bond

<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

2019 ◽  
Author(s):  
Andrew Heard ◽  
Stephen Goldup
Keyword(s):  
Active Site ◽  
Molecular Machines ◽  
Enantioselective Catalysis ◽  
Interlocked Molecules ◽  
End Groups ◽  
Mechanical Bond

<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

Synergistic effect of hydrophobic and hydrogen bonding interaction-driven viologen–pyranine charge-transfer aggregates: adenosine monophosphate recognition

Soft Matter ◽  
2021 ◽  
Author(s):  
Redhills L. Narendran ◽  
Archita Patnaik
Keyword(s):  
Hydrogen Bonding ◽  
Charge Transfer ◽  
Self Assembly ◽  
Adenosine Monophosphate ◽  
Fine Tuning ◽  
Hydrogen Bonding Interaction ◽  
Stimuli Responsive ◽  
Bonding Interaction ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Synergy between non-covalent interactions directing and fine-tuning self-assembly of electronically and electrostatically complementary molecules in water into stimuli responsive microscale aggregates.

NON COVALENT INTERACTIONS IN LARGE DIAMONDOID DIMERS IN THE GAS PHASE - A MICROWAVE STUDY

2017 ◽  
Author(s):  
Cristobal Perez ◽  
Melanie Schnell ◽  
Peter Schreiner ◽  
Norbert Mitzel ◽  
Yury Vishnevskiy ◽  
...  
Keyword(s):  
Gas Phase ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Vapour Pressure Isotope Effect on Evaporation from Pure Organic Phases - a PIMD Approach

2020 ◽  
Author(s):  
Luis Vasquez ◽  
Agnieszka Dybala-Defratyka
Keyword(s):  
Path Integral ◽  
Vapour Pressure ◽  
Density Functional ◽  
Isotope Effects ◽  
Tight Binding ◽  
Decomposition Analysis ◽  
Energy Decomposition Analysis ◽  
Special Importance ◽  
Non Covalent Interactions ◽  
Covalent Interactions

<p></p><p>Very often in order to understand physical and chemical processes taking place among several phases fractionation of naturally abundant isotopes is monitored. Its measurement can be accompanied by theoretical determination to provide a more insightful interpretation of observed phenomena. Predictions are challenging due to the complexity of the effects involved in fractionation such as solvent effects and non-covalent interactions governing the behavior of the system which results in the necessity of using large models of those systems. This is sometimes a bottleneck and limits the theoretical description to only a few methods.<br> In this work vapour pressure isotope effects on evaporation from various organic solvents (ethanol, bromobenzene, dibromomethane, and trichloromethane) in the pure phase are estimated by combining force field or self-consistent charge density-functional tight-binding (SCC-DFTB) atomistic simulations with path integral principle. Furthermore, the recently developed Suzuki-Chin path integral is tested. In general, isotope effects are predicted qualitatively for most of the cases, however, the distinction between position-specific isotope effects observed for ethanol was only reproduced by SCC-DFTB, which indicates the importance of using non-harmonic bond approximations.<br> Energy decomposition analysis performed using the symmetry-adapted perturbation theory (SAPT) revealed sometimes quite substantial differences in interaction energy depending on whether the studied system was treated classically or quantum mechanically. Those observed differences might be the source of different magnitudes of isotope effects predicted using these two different levels of theory which is of special importance for the systems governed by non-covalent interactions.</p><br><p></p>

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