Kinetic Control of Interpenetration in Fe-Biphenyl-4,4′-dicarboxylate MOFs by Coordination and Oxidation Modulation

Phase control in the self-assembly of metal-organic frameworks (MOFs) – materials wherein organic ligands connect metal ions or clusters into network solids with potential porosity – is often a case of trial and error. Judicious control over a number of synthetic variables is required to select for the desired topology and control features such as interpenetration and defectivity, which have significant impact on physical properties and application. Herein, we present a comprehensive investigation of self-assembly in the Fe-biphenyl-4,4'-dicarboxylate system, demonstrating that coordination modulation, the addition of competing ligands into solvothermal syntheses, can reliably tune between the kinetic product, non-interpenetrated MIL-88D(Fe), and the thermodynamic product, two-fold interpenetrated MIL-126(Fe). DFT simulations reveal that correlated disorder of the terminal anions on the metal clusters in the interpentrated phase results in H-bonding between adjacent nets and is the thermodynamic driving force for its formation. Coordination modulation slows self-assembly and therefore selects the thermodynamic product MIL-126(Fe), while offering fine control over defectivity, inducing mesoporosity, but electron microscopy shows the MIL-88D(Fe) phase persists in many samples despite not being evident in diffraction experiments, suggesting its presence accounts for the lower than predicted surface areas reported for samples to date. Interpenetration control is also demonstrated by utilizing the 2,2'-bipyridine-5,5'-dicarboxylate linker; DFT simulations show that it is energetically prohibitive for it to adopt the twisted conformation required to form the interpenetrated phase, and are confirmed by experimental data, although multiple alternative phases are identified due to additional coordination of the Fe cations to the N-donors of the ligand. Finally, we introduce oxidation modulation – the concept of using metal precursors in a different oxidation state to that found in the final MOF – as a further protocol to kinetically control self-assembly. Combining coordination and oxidation modulation allows the synthesis of pristine MIL-126(Fe) with BET surface areas close to the predicted maximum capacity for the first time, suggesting that combining the two may be a powerful methodology for the controlled self-assembly of high-valent MOFs.

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Inverse Design of Nanoporous Crystalline Reticular Materials with Deep Generative Models

10.26434/chemrxiv.12186681.v1 ◽

2020 ◽

Cited By ~ 3

Author(s):

Zhenpeng Yao ◽

Benjamin Sanchez-Lengeling ◽

N. Scott Bobbitt ◽

Benjamin J. Bucior ◽

Sai Govind Hari Kumar ◽

...

Keyword(s):

Self Assembly ◽

Metal Organic Framework ◽

Internal Surface ◽

Building Blocks ◽

Structural Features ◽

Generative Models ◽

Combinatorial Design ◽

Surface Areas ◽

Molecular Building Blocks ◽

Metal Organic

Reticular frameworks are crystalline porous materials that form via the self-assembly of molecular building blocks (i.e., 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 CO2 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.

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Inverse Design of Nanoporous Crystalline Reticular Materials with Deep Generative Models

10.26434/chemrxiv.12186681 ◽

2020 ◽

Author(s):

Zhenpeng Yao ◽

Benjamin Sanchez-Lengeling ◽

N. Scott Bobbitt ◽

Benjamin J. Bucior ◽

Sai Govind Hari Kumar ◽

...

Keyword(s):

Self Assembly ◽

Metal Organic Framework ◽

Internal Surface ◽

Building Blocks ◽

Structural Features ◽

Generative Models ◽

Combinatorial Design ◽

Surface Areas ◽

Molecular Building Blocks ◽

Metal Organic

Reticular frameworks are crystalline porous materials that form via the self-assembly of molecular building blocks (i.e., 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 CO2 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.

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Inverse Design of Nanoporous Crystalline Reticular Materials with Deep Generative Models

10.26434/chemrxiv.12186681.v2 ◽

2020 ◽

Author(s):

Zhenpeng Yao ◽

Benjamin Sanchez-Lengeling ◽

N. Scott Bobbitt ◽

Benjamin J. Bucior ◽

Sai Govind Hari Kumar ◽

...

Keyword(s):

Self Assembly ◽

Metal Organic Framework ◽

Internal Surface ◽

Building Blocks ◽

Structural Features ◽

Generative Models ◽

Combinatorial Design ◽

Surface Areas ◽

Molecular Building Blocks ◽

Metal Organic

Reticular frameworks are crystalline porous materials that form via the self-assembly of molecular building blocks (i.e., 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 CO2 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.

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A new three-dimensional manganese(II) coordination polymer based on the 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene ligand

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229616015965 ◽

2016 ◽

Vol 72 (11) ◽

pp. 895-900

Author(s):

Xin-Hua Lu ◽

Kai-Long Zhong

Keyword(s):

Coordination Polymer ◽

Crystal Engineering ◽

Self Assembly ◽

Three Dimensional ◽

Dimensional Structure ◽

X Ray Diffraction ◽

Ligand Coordination ◽

Metal Organic ◽

And Control ◽

Methyl Benzene

The self-assembly of coordination polymers and the crystal engineering of metal–organic coordination frameworks have attracted great interest, but it is still a challenge to predict and control the compositions and structures of the complexes. Employing multidentate organic ligands and suitable metal ions to construct inorganic–organic hybrid materials through metal–ligand coordination and hydrogen-bonding interactions has become a major strategy. Recently, imidazole-containing multidentate ligands that contain an aromatic core have received much attention. A new three-dimensional MnIIcoordination polymer based on 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene, namely poly[(ethane-1,2-diol-κO)(μ-sulfato-κ2O:O′){μ3-1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene-κ3N:N′:N′′}manganese(II)], [Mn(SO4)(C18H18N6)(C2H6O2)]n, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that there are two kinds of crystallographically independent MnIIcentres, each lying on a centrosymmetric position and having a similar six-coordinated octahedral structure. One is coordinated by four N atoms from four 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (timb) ligands and two O atoms from two different bridging sulfate anions. The second is surrounded by two timb N atoms and four O atoms, two from sulfate anions and two from two ethane-1,2-diol ligands. The tripodal timb ligand bridges neighbouring MnIIcentres to generate a two-dimensional layered structure running parallel to theabplane. Adjacent layers are further bridged by sulfate anions, resulting in a three-dimensional structure with3,4,6-ctopology. Thermogravimetric analysis of the title polymer shows that it is stable up to 533 K. The first weight loss between 533 and 573 K corresponds to the release of coordinated ethane-1,2-diol molecules, and further decomposition occurred at 648 K.

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Immobilization of D-allulose 3-Epimerase Into Magnetic Metal-Organic Framework Nanoparticles For Efficient Biocatalysis

10.21203/rs.3.rs-1140187/v1 ◽

2021 ◽

Author(s):

Kai Xue ◽

Chun-Li Liu ◽

Yankun Yang ◽

Xiuxia Liu ◽

Jinling Zhan ◽

...

Keyword(s):

Enzyme Activity ◽

Self Assembly ◽

Large Scale ◽

Catalytic Properties ◽

Metal Organic Framework ◽

Biological Functions ◽

Surface Areas ◽

Industrial Preparation ◽

Magnetic Metal ◽

Metal Organic

Abstract D-allulose is a rare low-calorie sugar that has many fundamental biological functions. D-allulose 3-epimerase from Agrobacterium tumefaciens (AT-DAEase) catalyzes the conversion of D-fructose to D-allulose. The enzyme has attracted considerable attention because of its mild catalytic properties. However, the bioconversion efficiency and reusability of AT-DAEase limit its industrial application. Magnetic metal-organic frameworks (MOFs) have uniform pore sizes and large surface areas and can facilitate mass transport and enhance the capacity for enzyme immobilization. Here, we successfully encapsulated cobalt-type AT-DAEase into the cobalt-based magnetic MOF ZIF-67@Fe3O4 using a self-assembly strategy. The AT-DAEase@ZIF-67@Fe3O4 nanoparticles had higher catalytic activity (65.1 U mg-1) and bioconversion ratio (38.1%) than the free AT-DAEase. The optimal conditions for maximum enzyme activity of the AT-DAEase@ZIF-67@Fe3O4 nanoparticles were 55°C and pH 8.0, which were significantly higher than those of the free AT-DAEase (50°C and pH 7.5). The AT-DAEase@ZIF-67@Fe3O4 nanoparticles displayed significantly improved thermal stability and excellent recycling performance, with 80% retention of enzyme activity at temperature range of 45-70°C and >45% of its initial activity after eight cycles of enzyme use. The AT-DAEase@ZIF-67@Fe3O4 nanoparticles have great potential for large-scale industrial preparation of D-allulose by immobilizing cobalt-type AT-DAEase into magnetic MOF ZIF-67@Fe3O4.

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