User:Acharyanarayan010

Density Functional Theory (DFT) calculations on Metal-Organic Frameworks(MOFs):

Metal-organic frameworks (MOFs), also known as porous coordination polymers (PCPs), are a class of hybrid organic-inorganic materials with high surface area, a permanent porosity with large internal pore volume and tunable pore sizes. They have a wide range of potential applications. These are taking as the superior catalyst to fulfil the fundamental challenge in the modern chemistry[20]. MOFs are constructed by interlinking metal ions or, more generally, metal-containing units with organic linkers. Through coordination bonds, they are thus creating crystalline frameworks. Due to the variety of the structural and chemical elements, some MOFs show unexpected characteristics, which sometimes cannot be adequately assessed experimentally. Theoretical approaches have been intensively employed in this case to investigate the systems at the atomic level. Computational modelling on these catalysts will offer many potentials to sort out the possibilities, ideas of synthetic planning and characterization and kinetics of the reaction.[20]

We examine the heterogeneous hydrogenation and hydroformylation reactions by the quantum chemical calculations. From the calculation, we consider the kinetics of these reactions (as mentioned above), characterize the metal-metal interaction in the bimetallic system and get the ideas about the reactive nodes in the framework. There are several challenges for modelling the catalytic activity by reasoning the electronic effect between the interaction of two metal ions. But it has been successfully overcome this challenge, which has studied in CuRhBTC[1].

One of the critical challenges in the calculation is the reliability and cost of the calculation. Density functional theory (DFT) is primarily applied in material sciences. MOFs is most promise catalyst in which transition metals are used to design the catalyst. It is a challenge to approach degenerate and non-degenerate electronic configuration of partially filled 3d orbitals. DFT can produce a highly accurate result in lower cost[20]. Besides the theory choosing the functionals is one of the challenges in the calculations. B3LYP functionals are unreliable calculation for the transition metal chemistry; however, both MO6-L and MO6 very suitable for the application in transition metal chemistry. Both give better performance than other basis sets. MO6-2X has improved performance but not ideal for the transition metal chemistry. MOF-HF also not suitable for the transition metal chemistry, which is less accurate than MO6-L and MO621. Thus, it is not possible to study reaction mechanisms using conventional MM methods. For structurally well-defined and small enough systems, DFT calculations are a convincing approach, especially in the field of localized catalytic reactions. We aim here to outline the suitability of DFT techniques to study catalysis in MOFs materials through examples from the recent literature[15]. In our previous research, DFT study used to model guest metal ions as active sites in the catalyst and to identify the favorable mechanism for the dissociation and absorption of the reactant on the guest metal ions1. Based on these researches, we try to use to model Co (II) ions in CuCoBTC and mechanism of hydrogenation of propylene will be studied. For the hydroformylation, the reaction will be modelled for the CuCoBTC to determine the reaction steps, Activation energies (reaction barrier) which provide the information about the rate-limiting steps. These steps will give catalytic activity on MOFs nodes.( Still need to add references)