Zeolitic Host–Guest Interactions and Building Blocks for the Self-Assembly of Complex Materials

MRS Bulletin ◽  
2005 ◽  
Vol 30 (10) ◽  
pp. 713-720 ◽  
Author(s):  
Thomas Bein

AbstractOrdered nanoscale pore systems such as those represented by zeolites offer many opportunities for the design of complex functional systems via self-assembly.With their large internal surface areas and tunable, well-defined crystalline pore structures that allow molecular sieving and ion exchange, zeolites can be adapted for numerous applications. The nanoscale reactors present in zeolite pore systems have been explored as structural templates for the spatial organization of numerous guests. Examples from various fields are discussed, such as the stabilization of organic dyes for the construction of energy transfer and storage systems, the construction of host–guest hybrid catalyst systems, and the encapsulation of conducting or semiconducting nanoscale wires and clusters. More complex, hierarchical forms of nanostructured matter become accessible when zeolite crystals are used as building blocks for the selfassembly of thin films or three-dimensional objects. A combination of weaker and stronger interactions ranging from dispersive forces, hydrogen bonding, and electrostatic interactions to covalent bonding can be used to build functional hierarchical constructs. Several examples and novel applications of such systems will be discussed, including oriented channel systems, chemical sensors, and hierarchical pore systems for catalytic reactions.

Author(s):  
Zhenpeng Yao ◽  
Benjamin Sanchez-Lengeling ◽  
N. Scott Bobbitt ◽  
Benjamin J. Bucior ◽  
Sai Govind Hari Kumar ◽  
...  

Reticular frameworks are crystalline porous materials that form <i>via</i> the self-assembly of molecular building blocks (<i>i.e.</i>, nodes and linkers) in different topologies. Many of them have high internal surface areas and other desirable properties for gas storage, separation, and other applications. The notable variety of the possible building blocks and the diverse ways they can be assembled endow reticular frameworks with a near-infinite combinatorial design space, making reticular chemistry both promising and challenging for prospective materials design. Here, we propose an automated nanoporous materials discovery platform powered by a supramolecular variational autoencoder (SmVAE) for the generative design of reticular materials with desired functions. We demonstrate the automated design process with a class of metal-organic framework (MOF) structures and the goal of separating CO<sub>2</sub> from natural gas or flue gas. Our model exhibits high fidelity in capturing structural features and reconstructing MOF structures. We show that the autoencoder has a promising optimization capability when jointly trained with multiple top adsorbent candidates identified for superior gas separation. MOFs discovered here are strongly competitive against some of the best-performing MOFs/zeolites ever reported. This platform lays the groundwork for the design of reticular frameworks for desired applications.


2020 ◽  
Author(s):  
Zhenpeng Yao ◽  
Benjamin Sanchez-Lengeling ◽  
N. Scott Bobbitt ◽  
Benjamin J. Bucior ◽  
Sai Govind Hari Kumar ◽  
...  

Reticular frameworks are crystalline porous materials that form <i>via</i> the self-assembly of molecular building blocks (<i>i.e.</i>, nodes and linkers) in different topologies. Many of them have high internal surface areas and other desirable properties for gas storage, separation, and other applications. The notable variety of the possible building blocks and the diverse ways they can be assembled endow reticular frameworks with a near-infinite combinatorial design space, making reticular chemistry both promising and challenging for prospective materials design. Here, we propose an automated nanoporous materials discovery platform powered by a supramolecular variational autoencoder (SmVAE) for the generative design of reticular materials with desired functions. We demonstrate the automated design process with a class of metal-organic framework (MOF) structures and the goal of separating CO<sub>2</sub> from natural gas or flue gas. Our model exhibits high fidelity in capturing structural features and reconstructing MOF structures. We show that the autoencoder has a promising optimization capability when jointly trained with multiple top adsorbent candidates identified for superior gas separation. MOFs discovered here are strongly competitive against some of the best-performing MOFs/zeolites ever reported. This platform lays the groundwork for the design of reticular frameworks for desired applications.


2020 ◽  
Author(s):  
Zhenpeng Yao ◽  
Benjamin Sanchez-Lengeling ◽  
N. Scott Bobbitt ◽  
Benjamin J. Bucior ◽  
Sai Govind Hari Kumar ◽  
...  

Reticular frameworks are crystalline porous materials that form <i>via</i> the self-assembly of molecular building blocks (<i>i.e.</i>, nodes and linkers) in different topologies. Many of them have high internal surface areas and other desirable properties for gas storage, separation, and other applications. The notable variety of the possible building blocks and the diverse ways they can be assembled endow reticular frameworks with a near-infinite combinatorial design space, making reticular chemistry both promising and challenging for prospective materials design. Here, we propose an automated nanoporous materials discovery platform powered by a supramolecular variational autoencoder (SmVAE) for the generative design of reticular materials with desired functions. We demonstrate the automated design process with a class of metal-organic framework (MOF) structures and the goal of separating CO<sub>2</sub> from natural gas or flue gas. Our model exhibits high fidelity in capturing structural features and reconstructing MOF structures. We show that the autoencoder has a promising optimization capability when jointly trained with multiple top adsorbent candidates identified for superior gas separation. MOFs discovered here are strongly competitive against some of the best-performing MOFs/zeolites ever reported. This platform lays the groundwork for the design of reticular frameworks for desired applications.


2017 ◽  
Vol 4 (3) ◽  
pp. 426-436 ◽  
Author(s):  
Jia Tian ◽  
Hui Wang ◽  
Dan-Wei Zhang ◽  
Yi Liu ◽  
Zhan-Ting Li

Abstract Studies on periodic porosity and related properties and functions have been limited to insoluble solid-state materials. Self-assembly provides a straightforward and efficient strategy for the construction of soluble periodic porous supramolecular organic frameworks (SOFs) in water from rationally designed molecular building blocks. From rigid tri- and tetra-armed building blocks and cucurbitu[8]ril (CB[8]), a number of two-dimensional (2D) honeycomb, square and rhombic SOFs can be generated, which is driven by CB[8]-encapsulation-enhanced dimerization of two aromatic units on the periphery of the multi-armed molecules. By utilizing the same three-component host−guest motif as the driving force, three-dimensional (3D) diamondoid and cubic SOFs can be obtained from tetrahedral and [Ru(bipy)3]2+-derived octahedral monomers and CB[8]. All of the 2D and 3D periodic frameworks are soluble in water, and are able to maintain the periodicity as well as the pore sizes in the solid state. 3D SOFs are highly efficient homogeneous polycationic frameworks for reversible adsorption of anionic species including organic dyes, peptides, nucleic acids, drugs, dendrimers and Wells-Dawson-typed polyoxametallates (WD-POMs). WD-POM molecules adsorbed in the [Ru(bipy)3]2+-based SOF can catalyse the reduction of proton to H2 upon visible-light sensitization of [Ru(bipy)3]2+, which allows multiple electron transfer from [Ru(bipy)3]2+ to WD-POM. This review summarizes the design, formation and characterization of this new family of self-assembled frameworks, highlights their applications as homogeneous porous materials and finally outlines some future research directions.


1992 ◽  
Vol 277 ◽  
Author(s):  
Geoffrey A. Ozin ◽  
Carol L. Bowes ◽  
Mark R. Steele

ABSTRACTVarious MOCVD (metal-organic chemical vapour deposition) type precursors and their self-assembled semiconductor nanocluster products [1] have been investigated in zeolite Y hosts. From analysis of in situ observations (FTIR, UV-vis reflectance, Mössbauer, MAS-NMR) of the reaction sequences and structural features of the precursors and products (EXAFS and Rietveld refinement of powder XRD data) the zeolite is viewed as providing a macrospheroidal, multidendate coordination environment towards encapsulated guests. By thinking about the α- and β-cages of the zeolite Y host effectively as a zeolate ligand composed of interconnected aluminosilicate “crown ether-like” building blocks, the materials chemist is able to better understand and exploit the reactivity and coordination properties of the zeolite internal surface for the anchoring and self-assembly of a wide range of encapsulated guests. This approach helps with the design of synthetic strategies for creating novel guest-host inclusion compounds having possible applications in areas of materials science such as nonlinear optics, quantum electronics, and size/shape selective catalysis.


2014 ◽  
Vol 1663 ◽  
Author(s):  
Garima Thakur ◽  
Kovur Prashanthi ◽  
Thomas Thundat

ABSTRACTSelf–assembly of molecular building blocks provides an interesting route to produce well-defined chemical structures. Tailoring the functionalities on the building blocks and controlling the time of self-assembly could control the properties as well as the structure of the resultant patterns. Spontaneous self-assembly of biomolecules can generate bio-interfaces for myriad of potential applications. Here we report self-assembled patterning of human serum albumin (HSA) protein in to ring structures on a polyethylene glycol (PEG) modified gold surface. The structure of the self-assembled protein molecules and kinetics of structure formation entirely revolved around controlling the nucleation of the base layer. The formation of different sizes of ring patterns is attributed to growth conditions of the PEG islands for bio-conjugation. These assemblies might be beneficial in forming structurally ordered architectures of active proteins such as HSA or other globular proteins.


2015 ◽  
Vol 6 ◽  
pp. 632-639 ◽  
Author(s):  
Ping Du ◽  
David Bléger ◽  
Fabrice Charra ◽  
Vincent Bouchiat ◽  
David Kreher ◽  
...  

Two-dimensional (2D), supramolecular self-assembly at surfaces is now well-mastered with several existing examples. However, one remaining challenge to enable future applications in nanoscience is to provide potential functionalities to the physisorbed adlayer. This work reviews a recently developed strategy that addresses this key issue by taking advantage of a new concept, Janus tecton materials. This is a versatile, molecular platform based on the design of three-dimensional (3D) building blocks consisting of two faces linked by a cyclophane-type pillar. One face is designed to steer 2D self-assembly onto C(sp2)-carbon-based flat surfaces, the other allowing for the desired functionality above the substrate with a well-controlled lateral order. In this way, it is possible to simultaneously obtain a regular, non-covalent paving as well as supramolecular functionalization of graphene, thus opening interesting perspectives for nanoscience applications.


2019 ◽  
Author(s):  
James D. Tang ◽  
Cameron Mura ◽  
Kyle J. Lampe

ABSTRACTShort peptides are uniquely versatile building blocks for self-assembly. Supramolecular peptide assemblies can be used to construct functional hydrogel biomaterials—an attractive approach for neural tissue engineering. Here, we report a new class of short, five-residue peptides that form hydrogels with nanofiber structures. Using rheology and spectroscopy, we describe how sequence variations, pH, and peptide concentration alter the mechanical properties of our pentapeptide hydrogels. We find that this class of seven unmodified peptides forms robust hydrogels from 0.2–20 kPa at low weight percent (less than 3 wt. %) in cell culture media, and undergoes shear-thinning and rapid self-healing. The peptides self-assemble into long fibrils with sequence-dependent fibrillar morphologies. These fibrils exhibit a unique twisted ribbon shape, as visualized by TEM and Cryo-EM imaging, with diameters in the low tens of nanometers and periodicities similar to amyloid fibrils. Experimental gelation behavior corroborates our molecular dynamics simulations, which demonstrate peptide assembly behavior, an increase in β-sheet content, and patterns of variation in solvent accessibility. Our Rapidly Assembling Pentapeptides for Injectable Delivery (RAPID) hydrogels are syringe-injectable and support cytocompatible encapsulation of oligodendrocyte progenitor cells (OPCs), as well as their proliferation and three-dimensional process extension. Furthermore, RAPID gels protect OPCs from mechanical membrane disruption and acute loss of viability when ejected from a syringe needle, highlighting the protective capability of the hydrogel as potential cell carriers for trans-plantation therapies. The tunable mechanical and structural properties of these supramolecular assemblies are shown to be permissive to cell expansion and remodeling, making this hydrogel system suitable as an injectable material for cell delivery and tissue engineering applications.


2018 ◽  
Author(s):  
Weimin Xuan ◽  
Robert Pow ◽  
Qi Zheng, ◽  
Nancy Watfa ◽  
De-Liang Long ◽  
...  

Template synthesis is a powerful and useful approach to build a variety of functional materials and complicated supramolecular systems. Systematic study on how templates structurally evolve from basic building blocks and then affect the templated self-assembly is critical to understand the underlying mechanism and gain more guidance for designed assembly but remains challenging. Here we describe the templated self-assembly of a series of gigantic Mo Blue (MB) clusters 1-4 using L-ornithine as structure-directing agent. L-ornithine is essential for the formation of such kind of template⊂host assemblies by providing directional forces of hydrogen bonding and electrostatic interactions. Based on the structural relationship between encapsulated templates of {Mo8} (1), {Mo17} (2) and {Mo36} (4), a plausible pathway of the structural evolution of templates is proposed, thus giving more insight on the templated self-assembly of Mo Blue clusters.


2019 ◽  
Author(s):  
Enrico Greco ◽  
Jing Shang ◽  
jiali zhu ◽  
Tong Zhu

<p>A graphene-based or carbon-based aerogel is a three-dimensional (3D) solid material in which the carbon atoms are arranged in a sheet-like nanostructure. In this study, we report the synthesis of low-density polymer-modified aerogel monoliths by 3D macro-assemblies of graphene oxide sheets that exhibit significant internal surface areas (982 m<sup>2</sup>/g) and high electrical conductivity (∼0.1 to 1 × 10<sup>2</sup> S/cm). Different types of materials were prepared to obtain a single monolithic solid starting from a suspension of single-layer graphene oxide (GO) sheets, and a polymer, made from the precursors 4-carboxybenzaldehyde and polyvinyl alcohol. These materials were used to cross-link the individual sheets by covalent bonds, resulting in wet-gels that were supercritically dried and then, in some cases, thermally reduced to yield graphene aerogel composites. The average densities were approaching 15-20 mg/cm<sup>3</sup>. This approach allowed for the modulation of distance between the sheets, pore dimension, surface area, and related properties. This specific GO/Polymer ratio has suitable malleability making it a viable candidate for use in conductivity 3D printing; it also has other properties suitable for energy storage, catalysis, sensing and biosensing applications, bioelectronics, and superconductors.</p>


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