High-throughput molecular simulations of metal organic frameworks for co2 separation: opportunities and challenges

Metal organic frameworks (MOFs) have emerged as great alternatives to traditional nanoporous materials for CO2 separation applications. MOFs are porous materials that are formed by self-assembly of transition metals and organic ligands. The most important advantage of MOFs over well-known porous materials is the possibility to generate multiple materials with varying structural properties and chemical functionalities by changing the combination of metal centers and organic linkers during the synthesis. This leads to a large diversity of materials with various pore sizes and shapes that can be efficiently used for CO2 separations. Since the number of synthesized MOFs has already reached to several thousand, experimental investigation of each MOF at the lab-scale is not practical. High-throughput computational screening of MOFs is a great opportunity to identify the best materials for CO2 separation and to gain molecular-level insights into the structure-performance relationships. This type of knowledge can be used to design new materials with the desired structural features that can lead to extraordinarily high CO2 selectivities. In this mini-review, we focused on developments in high-throughput molecular simulations of MOFs for CO2 separations. After reviewing the current studies on this topic, we discussed the opportunities and challenges in the field and addressed the potential future developments.European Research Council (ERC) under the European Union's Horizon research and innovation programme (ERC)Publisher versio

Database for CO2 separation performances of MOFs based on computational materials screening

Metal-organic frameworks (MOFs) are potential adsorbents for CO2 capture. Because thousands of MOFs exist, computational studies become very useful in identifying the top performing materials for target applications in a time-effective manner. In this study, molecular simulations were performed to screen the MOF database to identify the best materials for CO2 separation from flue gas (CO2/N-2) and landfill gas (CO2/CH4) under realistic operating conditions. We validated the accuracy of our computational approach by comparing the simulation results for the CO2 uptakes, CO2/N-2 and CO2/CH4 selectivities of various types of MOFs with the available experimental data. Binary CO2/N-2 and CO2/CH4 mixture adsorption data were then calculated for the entire MOF database. These data were then used to predict selectivity, working capacity, regenerability, and separation potential of MOFs. The top performing MOF adsorbents that can separate CO2/N-2 and CO2/CH4 with high performance were identified. Molecular simulations for the adsorption of a ternary CO2/N-2/CH4 mixture were performed for these top materials to provide a more realistic performance assessment of MOF adsorbents. The structure-performance analysis showed that MOFs with Delta Q(st)(0) > 30 kJ/mol, 3.8 angstrom 1 g/cm(3) are the best candidates for selective separation of CO2 from flue gas and landfill gas. This information will be very useful to design novel MOFs exhibiting high CO2 separation potentials. Finally, an online, freely accessible database https://cosmoserc.ku.edu.tr was established, for the first time in the literature, which reports all of the computed adsorbent metrics of 3816 MOFs for CO2/N-2, CO2/CH4, and CO2/N-2/CH4 separations in addition to various structural properties of MOFs.European Research Counci

Computational investigation of metal organic frameworks for storage and delivery of anticancer drugs

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Metal organic frameworks (MOFs) have been recently used in biomedical applications such as drug storage and drug delivery due to their large surface areas, high pore volumes, and tunable physical and chemical characteristics. In this study, we investigated MOF-74 materials for efficient storage and delivery of two anticancer drug molecules, methotrexate (MTX) and 5-fluorouracil (5-FU). We initially compared the results of our molecular simulations with the available experimental data for the MTX and 5-FU uptakes of various MOFs. Motivated by the good agreement between experiments and simulations, we computed MTX and 5-FU uptakes in 10 different MOF-74 materials having various physical and chemical properties. At low fugacity, MTX adsorption is favored over 5-FU since MTX has stronger interactions with the MOFs whereas at high fugacity, 5-FU adsorption is favored over MTX due to the entropic effects. Our results showed that MOF-74 materials outperform the MTX and 5-FU storage capacities of traditional materials such as polymeric nanoparticles and two dimensional layered nanomaterials. We also examined the diffusion of drug molecules in MOFs considering both single-component and mixture transport for the first time in the literature. Both drug molecules diffuse slowly in MOFs suggesting that MOF-74 materials are strong alternatives to traditional porous materials for delivery of MTX and 5-FU. This computational study will be useful to effectively identify the most promising MOFs for target drug delivery applications prior to experiments. Our results will also guide the experiments for the design and development of MOFs as anticancer drug carrier systems.Koc University Seed Fund Progra

High-throughput computational screening of the metal organic framework database for CH4/H-2 separations

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Metal organic frameworks (MOFs) have been considered as one of the most exciting porous materials discovered in the last decade. Large surface areas, high pore volumes, and tailorable pore sizes make MOFs highly promising in a variety of applications, mainly in gas separations. The number of MOFs has been increasing very rapidly, and experimental identification of materials exhibiting high gas separation potential is simply impractical. High throughput computational screening studies in which thousands of MOFs are evaluated to identify the best candidates for target gas separation is crucial in directing experimental efforts to the most useful materials. In this work, we used molecular simulations to screen the most complete and recent collection of MOFs from the Cambridge Structural Database to unlock their CH4/H-2 separation performances. This is the first study in the literature, which examines the potential of all existing MOFs for adsorption-based CH4/H-2 separation. MOFs (4350) were ranked based on several adsorbent evaluation metrics including selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability. A large number of MOFs were identified to have extraordinarily large CH4/H-2 selectivities compared to traditional adsorbents such as zeolites and activated carbons. We examined the relations between structural properties of MOFs such as pore sizes, porosities, and surface areas and their selectivities. Correlations between the heat of adsorption, adsorbility, metal type of MOFs, and selectivities were also studied. On the basis of these relations, a simple mathematical model that can predict the CH4/H-2 selectivity of MOFs was suggested, which will be very useful in guiding the design and development of new MOFs with extraordinarily high CH4/H-2 separation performances.European Research Council (ERC) under the European Union's Horizon research and innovation programme (ERC-Starting Grant

Facile synthesis of 2D Zn(II) coordination polymer and its crystal structure, selective removal of methylene blue and molecular simulations

A new coordination polymer {[Zn(μ3-ppda)(H2O)(μ-bpa)Zn(μ-ppda)(μ-bpa)]·4H2O}n (1) (ppda = 1,4-phenylenediacetate, bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by microwave-assisted reaction and characterized by elemental analysis, IR spectroscopy, single-crystal and powder X-ray diffractions. The asymmetric unit of 1 consists of two Zn(II) ions, two bpa ligands, two ppda ligands, one coordinated and four non-coordinated water molecules. In 1, ppda2− anions are linked the adjacent Zn(II) centers to generate 1D double-stranded chains. These chains are connected into 2D sheets by the bridging bpa ligands. Atomically detailed modeling was performed to compute single and binary component adsorption isotherms of H2, CO2, CH4 and N2 in complex 1. Results showed that 1 exhibits a high adsorption selectivity towards CO2 due to its high affinity for CO2. Results of this study will be helpful to guide the microwave-assisted reaction of coordination polymers to design promising adsorbents for gas storage and gas separation applications. The luminescent property of 1 and the selective removal of dyes in 1 have been also discussed. Results showed that 1 can be a potential candidate for luminescence applications and can selectively adsorb methylene blue (MB) dye molecules.Eskişehir Osmangazi Universit

Computer simulations of 4240 MOF membranes for H2/CH4 separations: insights into structure–performance relations

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Design of new membranes having high H2/CH4 selectivity and high H2 permeability is strongly desired to reduce the energy demand for H2 production. Metal organic frameworks (MOFs) offer a great promise for membrane-based gas separations due to their tunable physical and chemical properties. We performed a high-throughput computational screening study to examine membrane-based H2/CH4 separation potentials of 4240 MOFs. Grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were used to compute adsorption and diffusion of H2 and CH4 in MOFs. Simulation results were then used to predict adsorption selectivity, diffusion selectivity, gas permeability and membrane selectivity of MOFs. A large number of MOF membranes was found to outperform traditional polymer and zeolite membranes by exceeding the Robeson's upper bound for selective separation of H2 from CH4. Structure–performance analysis was carried out to understand the relations between MOF membranes' selectivities and their pore sizes, surface areas, porosities, densities, lattice systems, and metal types. Results showed that MOFs with pore limiting diameters between 3.8 and 6 Å, the largest cavity diameters between 6 and 12 Å, surface areas less than 1000 m2 g−1, porosities between 0.5 and 0.75, and densities between 1 and 1.5 g cm−3 are the most promising membranes leading to H2 selectivities >10 and H2 permeabilities >104 Barrer. Our results suggest that monoclinic MOFs having copper metals are the best membrane candidates for H2/CH4 separations. This study represents the first high-throughput computational screening of the most recent MOF database for membrane-based H2/CH4 separation and microscopic insight provided from molecular simulations will be highly useful for the future design of new MOFs having extraordinarily high H2 selectivities.European Research Council (ERC) under European Unio

Facile synthesis of 2D Zn(II) coordination polymer and its crystal structure, selective removal of methylene blue and molecular simulations

A new coordination polymer {[Zn(μ3-ppda)(H2O)(μ-bpa)Zn(μ-ppda)(μ-bpa)]·4H2O}n (1) (ppda = 1,4-phenylenediacetate, bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by microwave-assisted reaction and characterized by elemental analysis, IR spectroscopy, single-crystal and powder X-ray diffractions. The asymmetric unit of 1 consists of two Zn(II) ions, two bpa ligands, two ppda ligands, one coordinated and four non-coordinated water molecules. In 1, ppda2− anions are linked the adjacent Zn(II) centers to generate 1D double-stranded chains. These chains are connected into 2D sheets by the bridging bpa ligands. Atomically detailed modeling was performed to compute single and binary component adsorption isotherms of H2, CO2, CH4 and N2 in complex 1. Results showed that 1 exhibits a high adsorption selectivity towards CO2 due to its high affinity for CO2. Results of this study will be helpful to guide the microwave-assisted reaction of coordination polymers to design promising adsorbents for gas storage and gas separation applications. The luminescent property of 1 and the selective removal of dyes in 1 have been also discussed. Results showed that 1 can be a potential candidate for luminescence applications and can selectively adsorb methylene blue (MB) dye molecules. © 2017 Elsevier B.V

Zinc(II) and cadmium(II) coordination polymers containing phenylenediacetate and 4,4′-azobis(pyridine) ligands: Syntheses, structures, dye adsorption properties and molecular dynamics simulations

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Two new coordination polymers (CPs) – [Zn(µ4-ppda)(µ-abpy)0.5]n(1) and [Cd(μ3-opda)(µ-abpy)0.5(H2O)]n(2) (o/ppda = 1,2/1,4-phenylenediacetate, abpy = 4,4′-azobis(pyridine)) – have been synthesized by using Zn(II)/Cd(II) salts in the presence of o- and p-phenylenediacetic acid and abpy under hydrothermal conditions. Their structures have been characterized by FT-IR spectroscopy, elemental analysis, X-ray powder diffraction and single crystal X-ray diffraction techniques. The structural diversities were observed depending on anionic ligands and metal centers in the synthesized complexes. Complex 1 consists of a 2-fold interpenetrated 3D+3D→3D framework with pcu topology while complex 2 has a 2D structure with sql topology. The adsorption of methylene blue (MB) was studied to examine the potential of the title CPs for removal of dyes from aqueous solution. Molecular dynamics (MD) simulations were also performed to examine diffusion of MB in 1 and 2. Thermal and optical properties of two complexes were also discussed.Eskisehir Osmangazi Universites