2013 Fiscal Year Research-status Report
新しい炭素および有機金属フレームワーク材料に関するＤＦＴ計算
| Project/Area Number |
25390144
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | Carbon K4 / metal-organic framework / DFT / Cluster calculations |
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| Research Abstract |
In the first half of the project (from April, 2013 till at present) we have performed systematic high-level quantum chemical calculations for larger and size-tuned molecular clusters that are formed through cutting the sub-structures from the carbon K4 crystal. The geometry optimizations for selected K4 structures were carried out by imposing K4 symmetry restrictions, followed by estimation of the vibration fundamentals by performing harmonic frequency calculations. For some structures, full geometry optimizations were also performed. The results obtained at the DFT level of theory clearly show that cluster A (C46H28) and cluster B (C144H62) mimicking 3C-3D carbon K4 structures have partially metallic character due to their extremely close-lying HOMO and LUMO orbitals as compared with other covalently bonded carbon materials such as graphite and diamond. An intrinsic instability of these carbon K4 structures originates due to the removal of symmetry, evidently leading to distortion of the overall structure where some carbon centers become tetra-coordinated (4C) because of the formation of an additional bond with next-nearest-neighbor carbon centers. A recipe has been proposed to overcome these kinds of distortions where selected side-end C-H groups are replaced by fixation (or decoration) with relatively more rigid silica or zeolite fragments. The overall decorated structure thus obtained can be a good candidate for hydrogen storage applications due to its huge surface area and large void spaces.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
New work station HPC5000-Z820-SIP with installed Gaussian09 program packages was found very efficient in handling the computations at the DFT level of the theory. In addition, all the systematic calculations have been smoothly runned on our computational facilities. The results obtained has been reported at four International Conferences and Symposium as well as appearred as a regular paper in the Journal of "Research on Chemical Intermediates" in 2013.
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| Strategy for Future Research Activity |
In the second year of the project, systematic high level calculations would be extended for screening the most reliable and desirable structures for IRMOF materials. Our idea here for modified IRMOF structures is that the berillium-based connector part (metal oxide part) can be replaced either with the more basic metal oxides or more amphoteric ones. By increasing the basicity of oxide connector fragments one makes effectively tunable active sites for hydrogen or other gas interactions with their outer surfaces with relatively small energy barriers thus making them potential gas storage materials. It will be also effective to screen for the gas separation applications. Our preliminary computations have shown that the replacement of OBe4O12(C6) fragment for a single or multiple connectors with a number of other functional groups like OBe3Li2O12(C6), OAl2Li2O12(C6), OZn4O12(C6), Ti3MgO16(C6), Ti3ZnO16(C6), etc., have leading us to well promising results.
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| Expenditure Plans for the Next FY Research Funding |
We have planning to attend couple of International Conferences.
To dissiminate the results of new computations, we would like to attend International Conferences in Astana(Kazakhstan), Vienna (Austria) and in Okinawa.
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