Discovery of Novel Highly Functional Materials Organic Chemistry and the Synthesis of Covalent Organic Frameworks

Gas Storage and Separation Catalysis and Conductivity Evolving Components Structural Analysis Characterization


Discovery of Novel Highly Functional Materials

The INOMAR Center is currently developing the next generation of porous, crystalline materials. We employ the principles of reticular chemistry, whereby inorganic clusters (and/or metals) are linked with organic struts through strong bonds in a geometrically controlled fashion. Furthermore, the flexibility we have in choosing these building units, affords the resulting materials with unique opportunities for fine-tuning their pore metrics and environment, surface area, and overall topology.

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Our primary focus, with respect to research conducted, is the discovery of new extended, porous metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs). These classes of crystals have received a great deal of attention owing to their applications in clean energy storage, fuel cells, heterogeneous catalysis, thin films, chemical sensors and biomedicine among many others. Recently, members of our group have published work on the development of ZIF nanoparticle-coupled resonators for enhanced and selective gas detection.

Recent representative publications:

(1) Mixed-Metal Zeolitic Imidazole Frameworks and their Selective Capture of Wet Carbon Dioxide over Methane, N. T. T. Nguyen, T. N. H. Lo, J. Kim, H. T. D. Nguyen, T. B. Le, K. E. Cordova, H. Furukawa, Inorg. Chem. 2016, 55, 6201-6207.

(2) High Proton Conductivity at Low Relative Humidity in an Anionic Fe-based Metal-Organic Framework, T. N. Tu, N. Q. Phan, T. T. Vu, H. L. Nguyen, K. E. Cordova, H. Furukawa, J. Mater. Chem. A, 2016, 4, 3638-3641.

(3) New Topological Co2(BDC)2(DABCO) as Highly Active Heterogeneous Catalyst for Amination of Oxazoles via Oxidative C-H/N-H Couplings, T. N. Tu, K. D. Nguyen, T. N. Nguyen, T. Truong, N. T. S. Phan, Catal. Sci. Technol., 2016, 6, 1384-1392.

(4) Three-Dimensional Metal-Catecholate Frameworks and their Ultrahigh Proton Conductivity N. T. T. Nguyen, H. Furukawa, F. Gándara, C. A. Trickett, H. M. Jeong, K. E. Cordova, O. M. Yaghi, J. Am. Chem. Soc., 2015, 137, 13594.

(5) Introduction of Functionality, Selection of Topology, and Enhancement of Gas Adsorption in Multivariate Metal-Organic Framework-177. Y.-B. Zhang, H. Furukawa, N. Ko, W. Nie, H. J. Park, S. Okajima, K. E. Cordova, H. Deng, J. Kim, O. M. Yaghi, J. Am. Chem. Soc., 2015, 137, 2641.

(6) Selective Capture of Carbon Dioxide under Humid Conditions by Hydrophobic Chabazite-Type Zeolitic Imidazolate Frameworks, N. T. T. Nguyen, H. Furukawa, F. Gandara, H. T. Nguyen, K. E. Cordova, O. M. Yaghi, Angew. Chem. Int. Ed. 2014, 53, 10645.

(7) Dielectrophoresis-Assembled Zeolitic Imidazolate Framework Nanoparticle-Coupled Resonators for Highly Sensitive and Selective Gas Detection, Y. Hwang, H. Sohn, A. Phan, O. M. Yaghi, and R. N. Candler, Nano Lett., 2013, 13, 5271.

Organic Chemistry and the Synthesis of Covalent Organic Frameworks

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At INOMAR, the implementation of organic synthetic chemistry is crucial in preparing organic linkers used in the construction of MOFs and ZIFs. These organic linkers are typically synthesized from simple starting materials using efficient and effective synthetic procedures. The linkers designed here incorporate functional groups (typically carboxylates, imidazolates, pyrazolates, and triazolates among others) such that the organic unit can effectively form strong bonds with metal ions to stitch together an open, periodic framework (i.e. MOF and ZIF synthesis). The internal pore environment of MOFs and ZIFs are also amenable by either pre-functionalization of the organic linker or post-synthetic modifications. This allows us to incorporate functional groups such as amines, which can positively affect the properties of these materials.

Additionally, we utilize the key tenants of organic chemistry to develop another unique class of porous, crystalline materials known as covalent organic frameworks (COFs). COFs are distinctly unique in that their structures are composed completely of lightweight elements (C, B, O, N, etc.) that are linked together via strong covalent bonds (B-O, B-C, C-N, etc.). In order to construct a COF, the principles of reticular chemistry are also applied. Thus far, COFs have been assembled through boronate, borosilicate, imine, enamine, triazine, and hydrazone linkages created via condensation reactions. COFs structural features have been exploited in a wide array of applications, such as clean energy (hydrogen and methane) storage, semiconduction and photoconduction, supercapacitance, and toxic gas uptake.

Gas Storage and Separation

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Some of the most pressing concerns for the world today is the need for cleaner energy technology and to rid the atmosphere of toxic pollutants and greenhouse gases. At INOMAR, it is our desire to find a feasible and practical solution to these two issues. The composition of MOFs, ZIFs, and COFs provide us with a viable platform to accomplish these feats. The constituent building units of these materials can be systematically varied in order to perform certain applications. This has led us to design novel structures that are highly functional in gas adsorption and separation.

We are currently exploring the synthesis of MOFs and COFs that have a high capacity for hydrogen and methane storage, which in the future will lead to cleaner automobile fueling. Furthermore, we are focused on discovering new water-stable ZIFs that are capable of capturing carbon dioxide and separating it from automobile and factory exhaust. The adsorption of toxic gases and volatile organic compounds (i.e. CO, NH3, H2S, alcohols, etc.) is also being studied.

Recent representative publications:

(1) Mixed-Metal Zeolitic Imidazole Frameworks and their Selective Capture of Wet Carbon Dioxide over Methane, N. T. T. Nguyen, T. N. H. Lo, J. Kim, H. T. D. Nguyen, T. B. Le, K. E. Cordova, H. Furukawa, Inorg. Chem. 2016, 55, 6201-6207.

(2) Synthesis and Selective CO2 Capture Properties of a Series of Hexatopic Linker–Based Metal-Organic Frameworks P. T. K. Nguyen, H. T. D. Nguyen, H. Q. Pham, J. Kim, K. E. Cordova, H. Furukawa, Inorg. Chem., 2015, 54, 10065.

(3) Introduction of Functionality, Selection of Topology, and Enhancement of Gas Adsorption in Multivariate Metal-Organic Framework-177. Y.-B. Zhang, H. Furukawa, N. Ko, W. Nie, H. J. Park, S. Okajima, K. E. Cordova, H. Deng, J. Kim, O. M. Yaghi, J. Am. Chem. Soc., 2015, 137, 2641.

(4) Tailoring the Water Adsorption Properties of MIL-101 Metal-Organic Frameworks by Partial Functionalization N. Ko, P. G. Choi, J. Hong, M. Yeo, S. Sung, K. E. Cordova, H. J. Park, J. K. Yang, J. Kim, J. Mat. Chem. A, 2015, 3, 2057.

(5) Selective Capture of Carbon Dioxide under Humid Conditions by Hydrophobic Chabazite-Type Zeolitic Imidazolate Frameworks, N. T. T. Nguyen, H. Furukawa, F. Gandara, H. T. Nguyen, K. E. Cordova, O. M. Yaghi, Angew. Chem. Int. Ed. 2014, 53, 10645.

Catalysis and Conductivity

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Though our materials have been traditionally used for adsorption and separation of gases, we are also concentrating on developing new MOFs, ZIFs, and COFs for applications in heterogeneous catalysis. Our materials’ large surface areas and structured internal pore environments facilitate reactivity and selectivity in the catalysis of organic transformations, similar to what is observed in nature. We seek to exploit all constituents of the framework to discover collaborative, highly active catalysts that may not be synthesized otherwise. We view our catalytic materials as enzyme analogues.

We have recently expanded our attention to synthesizing thermally robust, chemically stable structures that serve as promising candidates for ion conduction. Furthermore, with our materials, we are seeking to systematically functionalize specific sites throughout the architecture in order to define a direct ion pathway and observe exceptional conductivity values.

Recent representative publications:

(1) An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation, T. L. H. Doan, T. Q. Dao, H. N. Tran, P. H. Tran, T. N. Le, Dalton Trans. 2016, 45, 7875-7880.
(2) High proton conductivity at low relative humidity in an anionic Fe-based Metal–organic framework, T. N. Tu, N. Q. Phan, T. T. Vu, H. L. Nguyen, K. E.Cordova, H. Furukawa, J. Mater. Chem A., 2016, 4, 3638-3641.

(3) New Topological Co2(BDC)2(DABCO) as Highly Active Heterogeneous Catalyst for Amination of Oxazoles via Oxidative C-H/N-H Couplings, T. N. Tu, K. D. Nguyen, T. N. Nguyen, T. Truong, N. T. S. Phan, Catal. Sci. Technol., 2016, 6, 1384-1392.

(4) Three-Dimensional Metal-Catecholate Frameworks and their Ultrahigh Proton Conductivity N. T. T. Nguyen, H. Furukawa, F. Gándara, C. A. Trickett, H. M. Jeong, K. E. Cordova, O. M. Yaghi, J. Am. Chem. Soc., 2015, 137, 15394.
(5) Azobenzene-Containing Metal-Organic Framework as an Efficient Heterogeneous Catalyst for Direct Amidation of Benzoic Acids: Synthesis of Bioactive Compounds L. T. M. Hoang, L. H. Ngo, H. L. Nguyen, C. K. Nguyen, B. T. Nguyen, Q. T. Ton, H. K. D. Nguyen, K. E. Cordova, T. Troung, Chem. Commun., 2015, 51, 17132.
(6) New Topological Co2(BDC)2(DABCO) as Highly Active Heterogeneous Catalyst for Amination of Oxazoles via Oxidative C-H/N-H Couplings T. T. Tu, K. D. Nguyen, T. N. Nguyen, T. Truong, N. T. S. Phan, Catal. Sci. Technol., 2015, 6, 1384.
(7) Tailoring the Optical Adsorption of Water Stable Zr(IV)- and Hf(IV)-Based Metal-Organic Framework Photocatalysts T. L. Doan, H. L. Nguyen, H. Q. Pham, N.-N. Pham-Tran, T. N. Le, K. E. Cordova, Chem. Asian J. 2015, 10, 2660.

Evolving Components

Historically speaking, there is a large disconnect associated with the functional capabilities between the synthetic and biological worlds. In principle, the synthetic world operates serially. All synthetic material is assembled from a relatively limited number of building blocks of similar shape and size and the end product serves a particular set of functions within the limitations of the material. This is in stark contrast to the biological world whose composition is derived from many different building blocks of unique shapes and sizes, leading to distinct compartments that are connected, yet function independently and intelligently. In essence, the components of the biological world operate in parallel performing a much wider array of functions.

It is our goal at INOMAR to bridge the divide that currently separates the biological and synthetic realms with respect to their functional capabilities. The first step that we are undertaking is to develop ordered materials, in which the building block components have the same geometry but evolve in their size. Indeed, this type of material has never been synthesized before. Therefore, it is our task to discover and develop the basic science of what we term, evolving components (ECOs). We expect ECOs to be the next generation of highly functional materials with a wide range of applications in solar energy conversion of CO2, H2O-splitting, and as transporter systems for drug delivery.

Structural Analysis Characterization

Due to their highly crystalline structure, MOFs, ZIFs, COFs, and ECOs are routinely characterized through X-ray diffraction (XRD) analysis. Here at MANAR, we use in-house single crystal XRD and powder XRD to solve the crystal structures of the materials we synthesize. We pride ourselves on the fact that every student has the opportunity to operate the instruments and hone their expertise in crystallography.

In order to check for thermal stability and architectural robustness, we frequently perform thermal gravimetric analysis and conventional porosity (N2 and Ar) tests, respectively. Furthermore, gas adsorption isotherms are carried out to quantify the uptake capacity of various gases. We also commonly analyze our materials for the ability to selectively adsorb gases from mixtures by performing kinetic breakthrough experiments. Throughout the course of a project, we may encounter other characterization techniques including, but not limited to: solution and solid-state NMR, microscopy (optical, transmission electron microscopy, scanning electron microscopy, and scanning tunneling microscopy), UV-Vis, FT-IR, and mass spectrometry.

Recent representative publications:

(1) High proton conductivity at low relative humidity in an anionic Fe-based Metal–organic framework, T. N. Tu, N. Q. Phan, T. T. Vu, H. L. Nguyen, K. E.Cordova, H. Furukawa, J. Mater. Chem A., 2016, 4, 3638-3641.

(2) New Topological Co2(BDC)2(DABCO) as Highly Active Heterogeneous Catalyst for Amination of Oxazoles via Oxidative C-H/N-H Couplings, T. N. Tu, K. D. Nguyen, T. N. Nguyen, T. Truong, N. T. S. Phan, Catal. Sci. Technol., 2016, 6, 1384-1392.

(3) Three-Dimensional Metal-Catecholate Frameworks and their Ultrahigh Proton Conductivity N. T. T. Nguyen, H. Furukawa, F. Gándara, C. A. Trickett, H. M. Jeong, K. E. Cordova, O. M. Yaghi, J. Am. Chem. Soc., 2015, 137, 15394.

(4) Synthesis and Selective CO2 Capture Properties of a Series of Hexatopic Linker–Based Metal-Organic Frameworks P. T. K. Nguyen, H. T. D. Nguyen, H. Q. Pham, J. Kim, K. E. Cordova, H. Furukawa, Inorg. Chem., 2015, 54, 10065.

(5) Introduction of Functionality, Selection of Topology, and Enhancement of Gas Adsorption in Multivariate Metal-Organic Framework-177. Y.-B. Zhang, H. Furukawa, N. Ko, W. Nie, H. J. Park, S. Okajima, K. E. Cordova, H. Deng, J. Kim, O. M. Yaghi, J. Am. Chem. Soc., 2015, 137, 2641.

(6) Selective Capture of Carbon Dioxide under Humid Conditions by Hydrophobic Chabazite-Type Zeolitic Imidazolate Frameworks, N. T. T. Nguyen, H. Furukawa, F. Gandara, H. T. Nguyen, K. E. Cordova, O. M. Yaghi, Angew. Chem. Int. Ed. 2014, 53, 10645.

(7) Engineering of Band Gap in Metal-Organic Frameworks by Functionalizing Organic Linker: A Systematic Density Functional Theory Investigation, H. Pham, T. Mai, N. N. Pham-Tran, Y. Kawazoe, H. Mizuseki, D. Nguyen-Manh, J. Phys. Chem. C 2014, 118, 4567.

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