| 研究課題/領域番号 |
14F04029
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| 研究機関 | 名古屋大学 |
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研究代表者 |
長岡 正隆 名古屋大学, 情報科学研究科, 教授 (50201679)
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| 研究分担者 |
PAKHIRA Srimanta 名古屋大学, 情報科学研究科, 外国人特別研究員
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| 研究期間 (年度) |
2014-04-25 – 2017-03-31
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| キーワード | PCP / MOF / 有機金属錯体 / 密度汎関数法 / ポテンシャルエネルギー面 / 回転障壁 / 量子化学計算 / 吸着 |
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| 研究実績の概要 |
The main goal of our research works is to design different kinds of porous coordination polymers (PCPs) or metal-organic frameworks (MOFs) constructed by the transition-metal cations Cu2+ or Zn2+ and various kinds of dicarboxylate organic ligands computationally, which have an important role in various fields of science such as gas separation, gas storage, guest alignment, heterogeneous catalysis, radical polymerization, nanotechnology etc.
We have constructed a few kinds of PCP model systems to explore the rotational dynamics, mechanism of gas storage and separation, and polymerization reactions mechanism in the PCPs channels. We have studied computationally these kinds of PCPs and computed their geometrical structure, stability, dynamical and rotational behavior, and rotational energy barriers of several bulkier rotational groups with respect to the most stable position. We have considered a model PCP system to study the aforementioned proposal.
To describe this model system computationally, we have used several hybrid density functional theories (DFTs) such as B3LYP and M06-2X with the correlation consistent double-ζ quality basis sets. To find out the most stable and unstable position of the organic ligand inside the model PCPs and the rotational barrier of it, we have done both rigid and relaxed scan. The rotational behavior of the bulkier rotational groups in the PCPs have been also studied here considering the model PCPs. The results are compared with the previous experimental results wherever available.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
PCPs are an intriguing class of porous crystalline materials in which the properties can be modulated by chemical functionalities on organic ligands. The design and construction of PCP architectures have been widely studied, and a variety of frameworks have been prepared through self-assembly processes. In particular, PCPs are currently receiving considerable attention in view of their possible functions in sorption, separation, guest alignment, the radical polymerization of polymethyl methacrylate (MMA) in the PCPs channels and the product tacticity.
In our present computations, we are doing the calculations of rotational barrier, structure and geometry, potential energy curves (PECs) of the bulkier rotational groups in these model PCPs for the first time. The PEC determines the most stable and unstable position of the bulkier groups in the PCPs and activation energy barrier have been also computed using the PEC.
The equilibrium geometrical parameters are well harmonized with the previous experimental values. In some cases, our results make a replica of the previous experiment. Our computed rotational or activation energy barriers are in accord with the previous experimental results. We are preparing a manuscript for publication right now considering the DFTs results. We believe this kind of our works will be focused on the radical polymerization of MMA in PCPs, chemical reactions as well as polymerization reactions in those PCPs channels, flexibility of PCPs or MOFs, the H2 or small gas molecules storage and gas separation.
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| 今後の研究の推進方策 |
We will continue the study using these kinds of model PCPs which are composed of transition-metal cations (Cu2+ and Zn2+) and bridging organic ligands using various kinds of DFTs. Using the optimized geometries of these PCPs, we will add the DABCO (1,4-Diazabicyclo[2.2.2]octane) molecule in the model PCPs to create the actual MOF environment. A unit cell model of real PCPs will be built by considering and adding the DABCO molecule, bridging organic ligands and transition metal cations.
For building the MM force field parameters, we will compute the NBO charges of each atoms in the model. We will also develop the force field parameters for these kinds of PCPs, especially by fitting the rotational barriers of benzene ring flip with the obtained DFT results, and check the consistency of our developed parameters with the previous experimental results.
Using the prepared PCPs parameters, we want to study the flexibility of the PCPs and ability to adsorb the guest molecule. We will try to apply the force field based parameters to grand canonical Monte Carlo (GCMC) simulations to investigate the adsorption and absorption characteristics of those kinds of PCPs. In addition, with the hybrid Monte Carlo/Molecular Dynamics (MC/MD) method, the radical polymerization reaction of poly(methyl methacrylate) (PMMA) will be simulated to understand the atomistic information of how the tacticity of the product polymer was controlled by using different PCPs composed of several kinds of organic ligands.
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