WHAT WE DO with The FRAMEWORKS...
...Mainly with Metal-Organic Frameworks (MOFs)
Gas Storage and Separation:
To isolate the pure and purer component from the gas mixture, separation and purification processes are critically important for the modern chemical industry. As MOFs are capable to capture targeted gas molecules selectively via physisorption methods, they are employed towards several gas sorption and separation directions, especially flue and biogas separation, hydrocarbon separations, noble gas separations, and so on. Even though the involvement of MOFs towards this gas sorption and separation direction is the maximum one, the excellent trade-off between sorption capacity, separation selectivity, easy regenerability, and recyclability is not yet achieved at the necessary level. We are actively working on these aspects particularly focusing on designing strategies on the water and/or moisture stability of the synthesized MOFs. Our target is to achieve the trade-off between the aforementioned parameters along with ultra-high stability of the developed MOFs so that they can be suitable for practical industrial entanglement.
Representative Reviews:
1) "pH-stable MOFs: Design Principles and Applications" Coord. Chem. Rev. 2023, 493, 215301.
2) "MOFs for CO2 Separation from Flue and Biogas Mixtures" Adv. Funct. Mater. 2022, 2207197.
3) "C2s/C1 Hydrocarbon Separation: The Major Step towards Natural Gas Purification by Metal-Organic Frameworks (MOFs)" Coord. Chem. Rev. 2021, 442, 213998.
Selected Articles:
1) "Highly Scalable Acid-Base Resistant Cu-Prussian Blue Metal-Organic Framework for C2H2/C2H4, Bio Gas, and Flue Gas Separations" Chemical Engineering Journal 2023, 460, 141795.
2) "Potential of a pH-Stable Microporous MOF for C2H2/C2H4 and C2H2/CO2 Gas Separations under Ambient Conditions" Inorg. Chem. 2022, 61, 18293-18302.
3) "A ‘Thermodynamically Stable’ 2D Ni‐MOF over a Wide pH Range with Scalable Preparation for Efficient C2s over C1 Hydrocarbon Separations" Chem. Eur. J. 2020, 26, 12624-12631.
4) "Immobilization of a Polar Sulfone Moiety onto the Pore Surface of a Humid Stable MOF for Highly Efficient CO2 Separation under Dry and Wet Environment through Direct CO2-Sulfone Interactions" ACS Appl. Mater. Interface. 2020, 12, 41177-41184.
5) "A Moisture‐Stable 3D Microporous Co(II)‐Metal–Organic Framework with Potential for Highly Selective CO2 Separation under Ambient Conditions'' Chem. Eur. J. 2018, 24, 5982-5986.
6) "A Water Stable Two-Fold Interpenetrating Microporous MOF for Selective CO2 Adsorption and Separation'' Inorg. Chem. 2017, 56, 13991-13997.
Proton Conduction:
Proton conduction (PC) having the paramount property for biological organisms and energy conversion in electrochemical systems such as polymer electrolyte fuel cells, Nafion and Nafion-like polymer membranes are also efficient proton conductors; however, the high costs and temperature limitations have driven a number of strategies towards the design of alternative materials, such as coordination polymers (CPs) and/or metal-organic frameworks (MOFs) and covalent organic polymers (COFs). Our target is to design and develop a simple yet powerful proton-conducting CPs/MOFs/COFs which not only will display exceptional ultra-high superprotonic conductivity with its excellent framework robustness but also will retain its potentiality for a longer time. For example, we have proposed a simple yet powerful template-assisted strategy for synthesizing proton-conducting MOFs where the templates remained in the frameworks with charge assist proportions which show exceptional proton conductivity in the order 10-1 S cm-1. This study reports one of the highest proton conductivity by MOFs thus far (Angew. Chem., Int. Ed. 2018, 57, 6662-6666).
Representative Reviews:
1) "Solid-State Proton Conduction Driven by Coordinated Water Molecules in Metal-Organic Frameworks and Coordination Polymers" ACS Energy Letters. 2022, 7, 4490.
2) "Covalent-Organic Frameworks (COFs) as Proton Conductors" Adv. Energy Mater. 2021, 2102300.
3) "Superprotonic Conductivity of MOFs and Other Crystalline Platforms beyond 10-1 S cm-1" Adv. Funct. Mater. 2021, 31, 2101584.
4) "Metal-Organic Frameworks and Other Crystalline Materials for Ultrahigh Superprotonic Conductivities of 10-2 S cm-1 or Higher" Chem. Eur. J. 2019, 25, 6259-6269.
Selected Articles:
1) "Coordinated Water Molecules Induced Solid-State Superprotonic Conduction by a Highly Scalable and pH-Stable Coordination Polymer (CP)" Mater. Chem. Front. 2023, 7, 3373-3381.
2) "A 2D Mg(II)-MOF with High Density of Coordinated Waters as Sole Intrinsic Proton Sources for Ultrahigh Superprotonic Conduction" ACS Materials Lett. 2020, 2, 1343-1350.
3) "A Co(II)-Coordination Polymer for Ultrahigh Superprotonic Conduction: An atomistic Insight through Molecular Simulations and QENS Experiments" J. Mater. Chem. A 2020, 8, 7847 - 7853.
4) "A Phosphate-based Silver-bipyridine 1D Coordination Polymer with Crystallized Phosphoric acid as Superprotonic Conductor" Chem. Eur. J. 2020, 26, 4607-4612.
5) "Polycarboxylates Templated Coordination Polymers: Role of Templates for Superprotonic Conductivities up to 10-1 S cm-1'' Angew. Chem., Int. Ed. 2018, 57, 6662-6666.
Luminescence & Sensing:
On account of the crucial role of metal ions in environmental and biological systems, the design and synthesis of metal-ion sensors have attracted considerable attention from researchers across the globe. Most important and essential elements such as Fe(III) in the human body, play vital functions in many biochemical processes. Similarly, the gradual gathering of Al(III) in human body with a high dose has the direct influence on the nervous system causing many symptoms of Al(III) toxicity for instance Alzheimer’s disease, Parkinson’s syndrome, and osteoporosis. On the other hand, large amounts of toxic organic small molecules and hazardous heavy metal ions are released into the environment with serious adverse effects on the environment and human health. Thus, it is very important to develop novel systems that have the ability to detect exclusively desired ions and toxic small organic molecules like nitromethane by convenient methods that are easy to apply, such as luminescence quenching by exploiting the luminescence nature of MOFs.
Representative Review:
1) "Critical Perspective on MOFs and its Composites for the Adsorptive Removal of Antibiotics from Wastewater Matrices" Cryst. Growth Des. 2023, 23, 7612–7634.
Selected Articles:
1) "A Water-stable Cationic SIFSIX MOF for Luminescent Probing of Cr2O72- via Single-Crystal to Single-Crystal Transformation" Small 2023, 2304581.
2) "pH-Stable Zn(II) Coordination Polymer as a Multiresponsive Turn-On and Turn-Off Fluorescent Sensor for Aqueous Medium Detection of Al(III) and Cr(VI) Oxo-Anions" Inorg. Chem. 2023, 62, 14124-14133.
3) "A Highly Selective MOF-based Probe for Turn-on Luminescent Detection of Al3+, Cr3+ and Fe3+ in Solution and Test Paper Strips through Absorbance Caused Enhancement Mechanism" Inorg. Chem. 2022, 61, 16952–16962.
4) "pH Stable Luminescent MOFs for the Selective Detection of Aqueous Phase Fe(III), and Cr(VI) Ions" Inorg. Chem. 2022, 61, 12396–12405.
5) "Porous Anionic Co(II) Metal-Organic Framework, with a High Density of Amino Groups, as a Superior Luminescent Sensor for Turn-on Al(III) Detection" Chem. Eur. J. 2021, 27, 11804-11810.
6) "Two Azo-functionalized Luminescent 3D Cd(II)-MOFs for Highly Selective Detection of Fe3+ and Al3+" New J. Chem. 2018, 42, 12865-12871.
Heterogeneous Catalysis:
In recent years, MOFs having well-defined crystal structures, modifiable pore topology, excellent tailorability, high surface areas have presented huge potential, especially in the field of heterogeneous catalysis. The catalytic property of MOFs can be readily controlled by the proper selection of metal ion and organic ligands. Based on the literature reports, there are different types of the active sites in the MOF which can catalyze the heterogeneous catalysis reactions (structural defect site, Lewis acid center, open metal site, and MOFs with a functional linker). Our target is to design and develop finely tuned robust MOFs suitable to display excellent catalytic activity with high yield and most desirable recyclability.
Selected Articles:
1) "A Highly Chemically Robust 3D Interpenetrated MOF Heterogeneous Catalyst for the Synthesis of Hantzsch 1,4-Dihydropyridines and Drug Molecules" Small 2024, 2309281.
2) "Highly Robust Metal−Organic Framework for Efficiently Catalyzing Knoevenagel Condensation and Strecker Reaction under Solvent-free Condition" Inorg. Chem. 2023, 62, 12989-13000.
3) "3D Co(II)-MOFs with Varying Porosity and Open Metal Sites toward Multipurpose Heterogeneous Catalysis under Mild Conditions" Cryst. Growth Des. 2019, 19, 5343-5353.
Metalo Hydrogen-Bonded Organic Frameworks (MHOFs):
Proton conductivity has long been investigated as a desirable property in a variety of materials, whether organic, inorganic or crystalline materials to construct proton exchange membranes (PEMs) for hydrogen fuel-cell applications. Among these, crystalline materials that include metal-organic frameworks (MOFs), coordination polymers (CPs), polyoxometalates (POMs), H-bonded organic frameworks (HOFs), and covalent organic frameworks (COFs) have attracted immense attention to the field of proton conducting materials, and have received great development in recent years.
The heart of the design and synthesis of new proton-conducting crystalline materials is the thoughtful selection of reaction substrates. In order to search for new crystalline materials as super-protonic conductors, we explored for the first time metalo hydrogen-bonded organic frameworks (MHOFs) as a new class of promising conducting materials.
Representative Reviews:
1) "Emerging Microporous HOF Materials to Address Global Energy Challenges" Joule 2022, 6, 22-27.
2) "Proton Conducting Hydrogen-bonded Organic Frameworks (HOFs)" ACS Energy Lett. 2021, 6, 4431–4453.
Selected Article:
1) "Metalo Hydrogen-Bonded Organic Frameworks (MHOFs) as New Class of Crystalline Materials for Protonic Conduction" Chem. Eur. J. 2019, 25, 1691-1695.