Molecular assembly at surfaces: progress and challenges

2017 ◽  
Vol 204 ◽  
pp. 9-33 ◽  
Author(s):  
R. Raval
Keyword(s):  
Building Blocks ◽  
Covalent Bonding ◽  
Molecular Assembly ◽  
Theoretical Modelling ◽  
Top Down ◽  
Molecular Systems ◽  
Natural Systems ◽  
Surfaces And Interfaces ◽  
Macromolecular Systems ◽  
Determine System

Molecules provide versatile building blocks, with a vast palette of functionalities and an ability to assemble via supramolecular and covalent bonding to generate remarkably diverse macromolecular systems. This is abundantly displayed by natural systems that have evolved on Earth, which exploit both supramolecular and covalent protocols to create the machinery of life. Importantly, these molecular assemblies deliver functions that are reproducible, adaptable, finessed and responsive. There is now a real need to translate complex molecular systems to surfaces and interfaces in order to engineer 21st century nanotechnology. ‘Top-down’ and ‘bottom-up’ approaches, and utilisation of supramolecular and covalent assembly, are currently being used to create a range of molecular architectures and functionalities at surfaces. In parallel, advanced tools developed for interrogating surfaces and interfaces have been deployed to capture the complexities of molecular behaviour at interfaces from the nanoscale to the macroscale, while advances in theoretical modelling are delivering insights into the balance of interactions that determine system behaviour. A few examples are provided here that outline molecular behaviour at surfaces, and the level of complexity that is inherent in such systems.

Multidimensional Numbers and the Genomatrices of Hydrogen Bonds

2010 ◽  
pp. 193-206
Author(s):  
Sergey Petoukhov ◽  
Matthew He
Keyword(s):  
Hydrogen Bonds ◽  
Genetic Code ◽  
Structural Features ◽  
Hyperbolic Type ◽  
Complex Numbers ◽  
Hypercomplex Numbers ◽  
Molecular Systems ◽  
Natural Systems ◽  
Double Numbers ◽  
Mathematical Properties

This chapter returns to the kind of numeric genetic matrices, which were considered in Chapter 4-6. This kind of genomatrices is not connected with the degeneracy of the genetic code directly, but it is related to some other structural features of the genetic code systems. The connection of the Kronecker families of such genomatrices with special categories of hypercomplex numbers and with their algebras is demonstrated. Hypercomplex numbers of these two categories are named “matrions of a hyperbolic type” and “matrions of a circular type.” These hypercomplex numbers are a generalization of complex numbers and double numbers. Mathematical properties of these additional categories of algebras are presented. A possible meaning and possible applications of these hypercomplex numbers are discussed. The investigation of these hyperbolic numbers in their connection with the parameters of molecular systems of the genetic code can be considered as a continuation of the Pythagorean approach to understanding natural systems.

Ligand-directed assembly engineering of trapezoidal {Ti5} building blocks stabilized by dimethylglyoxime

2019 ◽  
Vol 48 (27) ◽  
pp. 9916-9919 ◽  
Author(s):  
Qing-Rong Ding ◽  
Gui-Lan Xu ◽  
Lei Zhang ◽  
Jian Zhang
Keyword(s):  
Directed Assembly ◽  
Building Blocks ◽  
Molecular Assembly

A facile approach of ligand-directed assembly of trapezoidal {Ti5} building blocks was successfully established, which gave rise to interesting hybrid clusters including the first molecular assembly of porphyrin photosensitizer and titanium-oxo cluster.

scholarly journals Towards computer-guided tuning of the crystal packing of porous organic cages

2014 ◽  
Vol 70 (a1) ◽  
pp. C667-C667
Author(s):  
Angeles Pulido ◽  
Ming Liu ◽  
Paul Reiss ◽  
Anna Slater ◽  
Sam Chong ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Engineering ◽  
Molecular Sieves ◽  
Structure Prediction ◽  
Crystal Packing ◽  
Aromatic Aldehydes ◽  
Lattice Energy ◽  
Building Blocks ◽  
Molecular Assembly ◽  
Computational Techniques

Among microporous materials, there has been an increasing recent interest in porous organic cage (POC) crystals, which can display permanent intrinsic (molecular) and extrinsic (crystal network) porosity. These materials can be used as molecular sieves for gas separation and potential applications as enzyme mimics have been suggested since they exhibit structural response toward guest molecules[1]. Small structural modifications of the initial building blocks of the porous organic molecules can lead to quite different molecular assembly[1]. Moreover, the crystal packing of POCs is based on weak molecular interactions and is less predictable that other porous materials such as MOFs or zeolites.[2] In this contribution, we show that computational techniques -molecular conformational searches and crystal structure prediction- can be successfully used to understand POC crystal packing preferences. Computational results will be presented for a series of closely related tetrahedral imine- and amine-linked porous molecules, formed by [4+6] condensation of aromatic aldehydes and cyclohexyl linked diamines. While the basic cage is known to have one strongly preferred crystal structure, the presence of small alkyl groups on the POC modifies its crystal packing preferences, leading to extensive polymorphism. Calculations were able to successfully identify these trends as well as to predict the structures obtained experimentally, demonstrating the potential for computational pre-screening in the design of POCs within targeted crystal structures. Moreover, the need of accurate molecular (ab initio calculations) and crystal (based on atom-atom potential lattice energy minimization) modelling for computer-guided crystal engineering will be discussed.

Comparative Environmental Law

2019 ◽  
pp. 2-34
Author(s):  
Jorge E. Viñuales
Keyword(s):  
Environmental Law ◽  
Comparative Method ◽  
Comparative Law ◽  
Building Blocks ◽  
Top Down ◽  
Conceptual Approach ◽  
Research Project ◽  
Bottom Up ◽  
Present Volume ◽  
Functionalist Approach

This volume examines the building blocks of environmental law across different jurisdictions. More specifically, it provides a cartography of environmental law, with a focus on its underlying logic, main arrangements and their variations, and how it is embedded within the broader legal arrangements developed to tackle other questions. In this context, this preliminary chapter provides an overview of the comparative method as it applies to the overall research project leading to the present volume. It discusses descriptive and evolutionary approaches, the conceptual approach, the functionalist approach, the factual approach, legal formants, the contextualist approach, and legal transplants. It then considers a range of methodologies proposed by comparative law experts, including the bottom-up functionalism and top-down functionalism, before explaining the methodology used for the organization of this book. The chapter concludes by summarizing a tentative structure of comparative environmental law as a single overall technology.

scholarly journals Towards Building Blocks for Supramolecular Architectures Based on Azacryptates

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1733 ◽  
Author(s):  
Ana Miljkovic ◽  
Sonia La Cognata ◽  
Greta Bergamaschi ◽  
Mauro Freccero ◽  
Antonio Poggi ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Self Assembly ◽  
Hydrophobic Interactions ◽  
Building Blocks ◽  
Water Mixture ◽  
Molecular Systems ◽  
Supramolecular Architectures ◽  
Starting Point ◽  
The Difference ◽  
Supramolecular Devices

In this work, we report the synthesis of a new bis(tris(2-aminoethyl)amine) azacryptand L with triphenyl spacers. The binding properties of its dicopper complex for aromatic dicarboxylate anions (as TBA salts) were investigated, with the aim to obtain potential building blocks for supramolecular structures like rotaxanes and pseudo-rotaxanes. As expected, UV-Vis and emission studies of [Cu2L]4+ in water/acetonitrile mixture (pH = 7) showed a high affinity for biphenyl-4,4′-dicarboxylate (dfc2−), with a binding constant of 5.46 log units, due to the best match of the anion bite with the Cu(II)-Cu(II) distance in the cage’s cavity. Compared to other similar bistren cages, the difference of the affinity of [Cu2L]4+ for the tested anions was not so pronounced: conformational changes of L seem to promote a good interaction with both long (e.g., dfc2−) and short anions (e.g., terephthalate). The good affinity of [Cu2L]4+ for these dicarboxylates, together with hydrophobic interactions within the cage’s cavity, may promote the self-assembly of a stable 1:1 complex in water mixture. These results represent a good starting point for the application of these molecular systems as building units for the design of new supramolecular architectures based on non-covalent interactions, which could be of interest in all fields related to supramolecular devices.

2,2′-Biphospholes: Building Blocks for Tuning the HOMO-LUMO Gap of π-Systems Using Covalent Bonding and Metal Coordination

2011 ◽  
Vol 124 (1) ◽  
pp. 218-221 ◽  
Author(s):  
Hui Chen ◽  
Wylliam Delaunay ◽  
Liujian Yu ◽  
Damien Joly ◽  
Zuoyong Wang ◽  
...  
Keyword(s):  
Building Blocks ◽  
Covalent Bonding ◽  
Metal Coordination ◽  
Homo Lumo

scholarly journals Beyond icosahedral symmetry in packings of proteins in spherical shells

2017 ◽  
Vol 114 (34) ◽  
pp. 9014-9019 ◽  
Author(s):  
Majid Mosayebi ◽  
Deborah K. Shoemark ◽  
Jordan M. Fletcher ◽  
Richard B. Sessions ◽  
Noah Linden ◽  
...  
Keyword(s):  
Self Assembly ◽  
De Novo ◽  
Multiple Scales ◽  
Building Blocks ◽  
Icosahedral Symmetry ◽  
Protein Cages ◽  
Natural Systems ◽  
Wide Range ◽  
Stable Arrangement ◽  
Symmetric Structures

The formation of quasi-spherical cages from protein building blocks is a remarkable self-assembly process in many natural systems, where a small number of elementary building blocks are assembled to build a highly symmetric icosahedral cage. In turn, this has inspired synthetic biologists to design de novo protein cages. We use simple models, on multiple scales, to investigate the self-assembly of a spherical cage, focusing on the regularity of the packing of protein-like objects on the surface. Using building blocks, which are able to pack with icosahedral symmetry, we examine how stable these highly symmetric structures are to perturbations that may arise from the interplay between flexibility of the interacting blocks and entropic effects. We find that, in the presence of those perturbations, icosahedral packing is not the most stable arrangement for a wide range of parameters; rather disordered structures are found to be the most stable. Our results suggest that (i) many designed, or even natural, protein cages may not be regular in the presence of those perturbations and (ii) optimizing those flexibilities can be a possible design strategy to obtain regular synthetic cages with full control over their surface properties.

Sign in / Sign up

Export Citation Format

Share Document