Dynamers: Dynamic Molecular and Supramolecular Polymers

2010 ◽  
Vol 63 (4) ◽  
pp. 611 ◽  
Author(s):  
Jean-Marie Lehn

Dynamers are defined as constitutional dynamic polymers, i.e. polymeric entities whose monomeric components are linked through reversible connections and have therefore the capacity to modify their constitution by exchange and reshuffling of their components. They may be either of supramolecular or molecular nature depending on whether the connections are non-covalent interactions or reversible covalent bonds. They are formed respectively either by polyassociation with interactional recognition or by polycondensation with functional recognition between the connecting subunits. Both types are illustrated by specific examples implementing hydrogen bonding on one hand and formation of imine-type bonds on the other. The dynamic properties confer to dynamers the ability to undergo adaptation and driven evolution under the effect of external chemical or physical triggers. Dynamers thus are constitutional dynamic materials resulting from the application of the principles of constitutional dynamic chemistry to polymer science.

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1305
Author(s):  
Stefano Borocci ◽  
Felice Grandinetti ◽  
Nico Sanna

The structure, stability, and bonding character of fifteen (Ng-H-Ng)+ and (Ng-H-Ng')+ (Ng, Ng' = He-Xe) compounds were explored by theoretical calculations performed at the coupled cluster level of theory. The nature of the stabilizing interactions was, in particular, assayed using a method recently proposed by the authors to classify the chemical bonds involving the noble-gas atoms. The bond distances and dissociation energies of the investigated ions fall in rather large intervals, and follow regular periodic trends, clearly referable to the difference between the proton affinity (PA) of the various Ng and Ng'. These variations are nicely correlated with the bonding situation of the (Ng-H-Ng)+ and (Ng-H-Ng')+. The Ng-H and Ng'-H contacts range, in fact, between strong covalent bonds to weak, non-covalent interactions, and their regular variability clearly illustrates the peculiar capability of the noble gases to undergo interactions covering the entire spectrum of the chemical bond.


2018 ◽  
Vol 71 (4) ◽  
pp. 238 ◽  
Author(s):  
Manoj K. Kesharwani ◽  
Amir Karton ◽  
Nitai Sylvetsky ◽  
Jan M. L. Martin

The S66 benchmark for non-covalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 ‘high-level corrections’ are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66×8 problem set in particular, and for accurate calculations on non-covalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, whereas half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.


2021 ◽  
Vol 9 ◽  
Author(s):  
Harald Rupp ◽  
Wolfgang H. Binder

Additive manufacturing has significantly changed polymer science and technology by engineering complex material shapes and compositions. With the advent of dynamic properties in polymeric materials as a fundamental principle to achieve, e.g., self-healing properties, the use of supramolecular chemistry as a tool for molecular ordering has become important. By adjusting molecular nanoscopic (supramolecular) bonds in polymers, rheological properties, immanent for 3D printing, can be adjusted, resulting in shape persistence and improved printing. We here review recent progress in the 3D printing of supramolecular polymers, with a focus on fused deposition modelling (FDM) to overcome some of its limitations still being present up to date and open perspectives for their application.


2010 ◽  
Vol 6 ◽  
pp. 869-875 ◽  
Author(s):  
Thomas Pinault ◽  
Bruno Andrioletti ◽  
Laurent Bouteiller

Supramolecular polymers are linear chains of low molar mass monomers held together by reversible and directional non-covalent interactions, which can form gels or highly viscous solutions if the self-assembled chains are sufficiently long and rigid. The viscosity of these solutions can be controlled by adding monofunctional compounds, which interact with the chain extremities: chain stoppers. We have synthesized new substituted ureas and thioureas and tested them as chain stoppers for a bis-urea based supramolecular polymer. In particular, the bis-thiourea analogue of the bis-urea monomer is shown not to form a supramolecular polymer, but a good chain stopper, because it is a strong hydrogen bond donor and a weak acceptor. Moreover, all substituted ureas tested reduce the viscosity of the supramolecular polymer solutions, but the best chain stopper is obtained when two hydrogen bond acceptors are placed in the same relative position as for the monomer and when no hydrogen bond donor is present.


RSC Advances ◽  
2019 ◽  
Vol 9 (24) ◽  
pp. 13677-13695 ◽  
Author(s):  
Joel Sánchez-Badillo ◽  
Marco Gallo ◽  
Ricardo A. Guirado-López ◽  
Jorge López-Lemus

Non-covalent interactions, coordination numbers, RDFs, SDFs, CDFs, and transport properties for the [C4mim][Br] and [C4mim][CF3COO] ionic liquids were determined.


2020 ◽  
Vol 22 (28) ◽  
pp. 16421-16430 ◽  
Author(s):  
Ibon Alkorta ◽  
J. Grant Hill ◽  
Anthony C. Legon

Alkali–metal bonds formed by LiR and NaR (R = F, H, CH3) with each of the Lewis bases OC, HCN, H2O, H3N, H2S and H3P are investigated ab initio at the CCSD(T)/AVTZ and CCSD(T)/awCVTZ levels to characterise these non-covalent interactions.


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